Air-Leakage Control Manual

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-LeakageControlManual

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ResidentialConstructionDemonstrationProject)WI_R AD_,_INI_,[RATI()N' \_,J\. 'J_[


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DOE/BP--16 87DE92 011543

Air-LeakageontrolManualPrepared forBonneville Power Administration'sResidential ConstructionDemonstration ProjectUnder Contrac! Number 86-33-16

By Jim MaloneyUnder Washington State Energy OfficMemorandum of Agreement Number '723May 1991

DISTRIBUTION OF THIS DOCUMENT IS UNLIMIT


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Contents1. Introduction 12. Air Leakage in Homes 3

Forces Affecting Air Leakage 3Effects of Furced-Air Heating Systems 3Leaks in System Components 3Differential Pressure 3

Benefits of Controlling Air Leakage 4Energy 4Indoor Air Quality 5Moisture and the Building Shell 5,

3. Earlier Approaches for Controlling Air Leakage 7The "Poly" Approach 7The Advanced Drywall Approach 7Problems with Earlier Approaches 8

4. The SIMPLE.CS System 9Floors over Crawlspaces 9Floors over Basements andon Second Story 10Connections between Floor and Exterior Wall 10Intersections of Interior Partitionand ExteriorWall 10Intersections of InteriorPartitionand Exterior Ceiling 11Forced-Air Heating Systems 11

5. SIMPLE.CS Analysis and Planning Procedure 13


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Appendix A. Air Sealing Checklist A-

Appendix B. Completed SIMPLE.CS Analysis and PlanningPi ocedure for Sample Home B-Outline of SIMPLE.CS Analysis and Planning Procedure B.Plans for Sample Home: Main Level, Upper Level, and Section B-Completed Air Sealing Checklist for Sample Home B

Appendix C. Sealing Materials C-Adhesives C-Caulks C-Gaskets CFoams CSheet Materials C

Appendix D. Detail Drawings DFigure 1. Typical "ADA" Ceiling Detail DFigure 2. Intersection of Interior and Exterior Wall D-Figure 3. "ADA" Wall Section at First and Second Floors D-Figure 4. SIMPLE.CS Ceiling at Second Floor Level D-Figure 5. SIMPLE.CS Ceiling at Exterior Wall/Floor Joint D-Figure 6a. Intersection of Interior and Exterior Wall (Type 1) D-Figure 6b. Intersection of Interior and Exterior Wall (Type 2) D-Figure 7. Intersection of Interior Wall and Exterior Ceiling D-Figure 8a. Sealing at Plumbing Pene_ations D-Figure 8b, Sealing for Bathtub at Subfloor Cutout D..1Figure 9. Sealing Electrical Penetrations D-I


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Section. IntroductionThis manual is for builders _ designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the "how _ultlwhy"of controlling air leakage by means of a system called the "Simple Caulk andSeal" (SIMPLE.CS) system.This manual is composed of the six sections and four appendixes describedbelow.Section 1 provides an overview of the purpose and contents of the manual.Section 2 discusses the forces that affect air leakage in homes and the benefitsof controlling air leakage.Section 3 discusses two earlier approaches for controlling air leakage and theproblems with these approaches.Section 4 describes the SIMPLE.CS system, lt outlines the standard com-ponents of the building envelope that require sealing and provides guidelinestbr sealing them.Section 5 outlines a step-by-step procedure for analyzing and plarming the seal-ing effort. Ttle procedure includes (1) identifying ,areas to be sealed, (2) de-termining the most effective and convenient stage of construction in which lodo the sealing, and (3) designating the appropriate crew member or trade to beresponsible for the sealing.Appendix A is an Air Sealing Checklist, indicating components of and penetra-tions in the building envelope that may require sealh_g. The checklisl is a pl_m-ning tool designed for indicating the areas to be sealed, the type of sealant tobe used, the timing of the sealing, and the person responsible for doing ii.Appendix B consists of a completed analysis and plaiming procedure for asample Northwest home. lt includes (1) an outline of the steps involved,(2) plans and sections for the smnple home, and (3) a completed Air SealingChecklist for the home.Appendix C discusses various sealing materials: adhesives, caulks, gaskets,tbams, and sheet materials.Appendix D includes det',dl drawings illustrating various points in the textfFigures 1-9).


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Section. AirLeakageInHomesForcesAffectingAir ..roeor o artomo o ou,or' off ,Leakage and fans, Of thethree, the,stackeffect causesthe mostuncontrolledairexchange, It occurs when there's a wintertime temperature difference betweenthe air inside a home and outside. The difference in air densities causes cold

outside air to infiltrate at the lower levels of a home _mdthe inside air to ex-filtrate at the upper levels.Wind forces operate as you might think_infiltration on the windward orpositive-pressure side of a home and exfiltration on the leeward or negative-pressure side. Wind effects on the uncontrolled air exchange vary with localshielding and terrain conditions at the site. A home at an exposed site mayhave wind-induced infiltration three to tbur times as large as one moreprotected.We have little control over the outdoor temperature or the strength or directionof the wind. Therefore, the only effective approach for minimizing stack 'andwind-tbrce effects on infiltration is to minimize the "holes" through which theair can flow.

Effectsof Forced-Air Fo_ed-_r heating systems affect the air exchm, ge rates in homes in two ways:Heating Systems through leaks in the system components and by creating a pressure differencebetween parts of the home and the outside.Leaksin System If the ductwork or the air handler is outside the heated space, the joints, seams,Components filter slots, plenum connections, and maintenance openings leak air, unlessthey are adequately sealed. The leakage is greatest when the system is on,

because of the higher pressure differences created by the fan, But there is someleakage even when the fan is off, because the distribution system, commonlylocated in crawlspaces, basements, or attics, is effectively part of the buildingenvelope, For example, return ductwork in the attic has warm indoor air risinginto it even with the system off. This ,air can then leak into the attic. Thisleakage reduces the pressure hl the lower portion of the home and alloy, s air toleak from the crawlspace into the ;;upply ducts and into the house.

DifferentialPressure A |orced-air system works by creating a diftbrence in pressure between livearea where the supply registers are located and the area where the returns arelocated. A home with a forced.air system typically has a positive net pressureat t_ perimeter of the home and a negative net pressure near the central por-tion. For example, the bedrooms are usu_dly pressurized and the hallway isdepressurized.The differential pressure leads to increased exfiltration in the bedrooms,because there is a greater difference in air pressure between the bedrooms _uztloutside, It similarly leads to increased infiltration in the central portions of thehome, commonly from the crawlspace, because of the proximity of large open-ings in the floor for plumbing and the ducts themselves. This situation is madeworse whenever the bedroom doors are closed or lhc design of tl_ system issuch that the return side is "starved" for air.

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BenefitsofControl- Uncontrolle,'.,".,,k_,g_,,_,_1o,11_.'fc,,_,1o,,l_yhennualeathzgtulingAirLeakage cooling.l_,u,,,,_,,,,,h_t'_,ivo._,._fve,,,..,_o,,,_y._,long-term durability _,t"he structure ilself.Energy The heating load du.' to infiltration can make up about a quarter to a thirdhome's total space,.Iteat rettuirement, Often in newer homes built with m

ficient windows and doors and higher levels of insulation hl the w_dls, floand ceilings, lillle allention is paid 1ocontrolling air leakage, Builders bethey construct "quality" homes, and don't believe that a little intillration"that big a deal, after all, a house has got 1o breathe."Of course, the size of the "deal" has a l et to do with the price oi'energy aseverity of the climate in which the home is built. The following graph sthe ,mnu_dheating load ,andthe _umual casi of heating _m1800-square foohome hl the Ptmhmd area, These estzmates are lhr a reasonably wellqnsuhome with varying degrees of infiltration control, From abou! 0,3 air cluper hour (ACH) to a little over 0,5 ACH, the annual heating cost wouldincrease by about $120, assuming an electric rate of 4,5 cents per kilowallhour, lt might cost about $250 extra to build the house Io the 0.3 ACH levwhich would yield a simple payback in about 2 years.

AnnualHeatingLoadandHeatingCostforHome(1800sqin Podland,Oregon

3640 _ii'i" ii "iiiiii[iiiiiiiiiiiiiiiiiiii[ !ii iiiii_-.iii!i_iiiiiiill "$60% 38- -_ $50

o '$30...J:_ 28- -$20:t: -$124

22' ' $00,3 0,4 0,5 0.6Air Changes per Hour[,,,lRAnnualLoad _i_i_lAnnualCost /IIIIIIII __ I .

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IndoorAirQuality But now that the home has been built to save on heating energy, even morebenefits are possible. If major pollution sources are not brought into the home,it's possible for the indoor Idrquality of the low-leakage home to be betterth,'m that in the old one that "breathed." 'When the ventilation rate of the homeis less dependent on the uncontrolled air leakage, it's easier for a small mechan-ic',d ventilation system to adequately provide fresh air when and where it'sneeded. The system can be as simple as high-quality bath and kitchen fanscombined with fresh air inlets for bringing outside ,airinto the home.In the case of some pollutants, like radon, an air-tight floor or ba,sement can ac-tu_,lly reduce the interior concentrations. Even tightening a ceiling c_m reducethe entry of radon into a home by reducing the effective height of the stack ef-fect, which pulls the soil gasses into the basement or from the crawlspace andinto the home.If it's fairly mild outside and there is no appreciable wind, the forces due tostack effect and wind pressure are absent. Without a mechanical ventilationsystem _here would be no ',titexchange iii the home----_ven with the windowsopen. The motto for good indoor air quality might be "Build tight ,andventi-late fight."

MoistureandtheBuilding Another benefit of reducing the amount of air leakage in homes is a decreaseShell in the potenti_d for future structural problems due to moisture-induced decay ofthe wood structure. As inside air leaks ttu'ough w,'dls and ceilings, ii c_u'rieswith it large amounts of water vapor generated within the home. The amountof moisture transmitted into building envelope assemblies by the leakage ofmoisture-laden air is much greater than that transmitted by diffusion. If thewall or roof sheathings are at a temperature below the dew point, a certainamount of the water vapor will be le ft behind, because it will condense on thecool surfaces. If this continues over an extended period of time, enough mois-ture can collect to support molds, fungi, and insect pests.If the drying potential of the wall or ceiling assembly is not sufficient toremove the accumulated moisture during yearly cycles, there is a highlikelihood of structural damage over time. Reducing the air leakage _mdproviding a mechanical ventilation system are key strategies in extending thelife of wood structures.

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Section. EarlierApproachforControllingirLeakageTwo approaches previously recomnlended for controlling air leakage were the"Poly" Approach and the Adv_mced Dryw_dl Approach,

The "Poly" Early in ttle 1980s, some builders in the Northwest began experimetzting withApproach various teclmiques to linai! air leakage, One technique w;_sreferred to as theCo ltmuc us Polyethylene Air-Vapor Barrier" (,PAVB), II was adapted fromthe CanMi,'ul R-2000 building program _mdfrom similar techniques used infactory-constructed houses in Sweden, The PAVB approach consisled ofinstalling a continuous layer of polyethylene over the inner surface of the ex-terior shell of the buildhag--except where doors and windows were, At jointsand se_uns the poly was carefully lappe(l and sealed,Polyethylene sheet nmterial was chosen because it could function as the air bar-rier and ;ts the moisttue-dit'lhsion retarder, 'Itle idea was that since lhc samematerial could serve both flmctions, there would be some cost savings, Toensure conlinuity, some pieces of poly had Io be installed during lhc rough-fr_mling stages of construction so that, later, lhc larger pieces covering lhc bulkof the walls and ceiling could be lapped and sealed lo the pieces already inplace, The most common areas requiring lapping _mdse_ding were the intersec-lions t)f l hc inlerior paililions with exlerior walls and ceilings.Any pelletratious in the PAVB had lo be carefully treated, Because poly-ethylene is very tlexible, ii required some support or solid backing in order tobe sealed around things like electrical boxes and duct penetrations, In addition,there were other complex Iricks involved in getting a good seal around windowand door frames,A number of builders had success with this approach, However, many whotried it found it too complicated for their continued use, Many of the homesbuill with lhc technique eqded up only slighlly less leaky Ih[m they would havebeen without it, This resull was less a fault of lhc PAVB system than of lhclack of attention to the forced-Nr heating systems and the multitude of minorpenetrations in the building envelope,The PAVB system was more appropriate tbr t'actory-coastructed houses forwhich the materials could be assembled in a relatively clean area, protectedfrt)m the weather. In outtlo()r c(_nstmclitm, faced with rain, ct)ld lemperalttres,and we! sawdust, builders had (lifficulty carrying oul the air-barrier details.

--.--Drywallpproach ,j.. ,,,in


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They recogtfized the problems with the PAVB system and proposed splittithe air-barrier and diffusion-retarder functions into tWO construction com.ponents.Moisture difliJsion could be handled hl a tmmber of ways. A builder coulfaced insulation, foil-backed gypsum wallboard, or vapor-retarder paint tovide the required barrier, Because a moisture retarder's effectiveness is ptionai to its surface area, a 95 percent vapor retarder is about as good as apercent retarder--.lt can tolerate more imperfection thml an air barrier canAn ab' barrier needs to be able to resist air-pressure differences. Thereforethey thought, "Why not use parts of the building envelope that already dothat_like the gypsum-board wails _mdceilings and the plywood floor?"trick on the air-barrier side was how to get the dift'erent structural componeof the house to work together. The solution was to recognize that "effectivcontinuous works a.swell as continuous.While the drywall and the plywood subtloor served well as air-b;u'rier surfwhat was needed was some way to com_ect one surface to tuiother. The Asolution was to use a compressible gasket between components at transitio(see Figure 1; Figures 1-9 are shown irl Appendix D). The gasket materiacould be applied prior to hanging the drywall, for example, ,andeffectivelyc,'u'rythe air.barrier surface from subfloor to bottom plate to drywall.The early versions of ADA recommended running the gypsum board betwtie last stud in a partition wall and the exterior wall framing, lt also suggerunning the gypsum board between the top plate of an interior partition anunderside of the trusses or ceiling joists. These details were later modifiedpractice to those now used (see Figure 2). Over time, and with a few mormodifications, builders around the country were using ADA in one form oanother and its name had evolved into the "Advanced Drywall Approach."But, even with ADA, thele were problems and requests for "a shnpler wawas still necessary to have the framing crew apply gasketing between strutural members during construction (see Figure 3), And many of the air-seatasks still had to be completed before the building shell was weathertight.

Problemswith The problems with the earlier air-barrier approaches were partially a resuEarlierApproaches t_ techniques themselves and paxti',dly a result of the impracticality of implementing them in the real world of construction. They require detail-oriented work at an inappropriate stage of constru They require an interruption in the normal flow of work on a building, They tend to emph,xsize techniques for sealing the tloor, wall, and ce

assemblies at the cost of attention to sealing the multitude of penetratt They fail to recognize the law of (liminishing returns, resulting in greeffort and increased costs.Air-tightening a building is not an all-or-nothing proposition, The earlierproaches were too comprehensive, too complicated, ,'rodtoo untrusting ofsimpler solutions. As a result of tiffs realization, ;ulother approach was(levehq_ed t_ ad(hvss the mt)st common requests of buihlers. This new approach, calle(I the "Simple Caulk and Seal" (SIMPLE,CS) syslem, is (liscin the next section.

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Section. TheSIMPLE.CSSystemTile "Simple Caulk _mdSEM" (SIMPLE.CS) systenl attempts to minhnize tileeffort required to reduce air leakage in residential buildings, The idea behindthis system is simple--reduce the number of sealing steps and delay them untilas late as possible in the construction proce,ss, This approach is based on tilenotion that no matter how good a,job i:_done on the major components (likewalls and ceilings)i dnless attention is pa!d to ,di the penelzations, the ovendlquality of the job will suffer,The SIMPLE.CS system consists of only two parts: The plywood subfloor and gypsum-board wall ,and ceiling finishes (excel-

lent air.barrier materials that represent 90 percent of the air barrier in theSIMPLE.CS system), A standard set of other components and penetrations in the building en.

velope that require sealing,In or(lcr to coordinate the Ml-sealing effort, a step-by-step an_dysis and ph'tu-ning procedure has been developed (see Section 5), This procedure isdesigned to help a builder or designer deternline what needs to be sealed, whenill the construction process file setding should be done, and who should do ii,The ,malysis and planning procedure includes taking an inventory of potentialleakage sites for a specific home, To aid in their identification, a comprehen-sive checklist of possible leakage sites is included in Appendix A, Aliexample of this procedure, completed for a sample home, is included inAppendix B,Guidelines for sealing the standard components of the building envelope arepresented below with a focus on details typical in site-built homes in thePacific Northwest, Possible penetrations in the building envelor)e that ,risemay require sealing are included in Section 5,Co_tstruction materials and techniques other that those presented may requiremodifications of these recommendations, Suggestions for appropriale caulkingand other sealing materi',ds are provided in Appendix C,

Floorsover ,. spite of what was saidearlier about sealint3after tile home is l'r_unedandCrawlsnaces floors over crawlspaces are easiest ,o seal while tile sublloor is beinglaid (though it can be (lone at a later time), Most builders use a(thesives in ad-dition to naris or staples to attach the tongue and groove plywood or wafer-board to the floor structure, This provides an excellent oppollutfity to seal thetloor, The following procedure will result in ataair-tight sublloor that runs t:oll,,linuously under ali exterior and interior walls, To seal the short dimension of the sheet, apply a continuous I)ead ot'

glue on the joist at the butt joint of the floor shealhing.



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To seal the long dimension, simply add a bead of adhesive to tile btom side of the tongue before laying the sheet down and snugginginto piace. By placing the glue on the bottom of the tongu,e, you ensuthat any glue forced out when the sheets are brought together will squout on the underside, not on the top where it can be tracked around,

Floorsover Tho main leakage site in these floors is at the rinl joist area, These tloors cBasementsndon usually be sealed rifler framing, unless there will be constricted access, Foexample, access would be limited if the last .joist bay was only 12 inches wSecondStory o,u,_ joists were only 2 x 8s (which would leave 7 1/2 inches of vertical sin which to work once the subfloor above was laid). A suggested approachto handle the insulation, air'se_ding, and moisture diffusion ali at the same Instal l several inches of rigid insulation as a thick block against th

rim joist and caulk around ali edges---to the mudsill or top plate,the,joist on eitller side, and to the subfloor above (see Figure 4), For a basement home, seal the joint between the mudsili and the f

dation. For a two.story home, seal between the top plate of the lower wallthe gypsum-board wall covering.

Connections Typically, builders use caulks or gaskets under the bottom plate of an extebetween Floor and w.H and then apply another gasket or drywall adhesive between the bottomExteriorWall plate ,and the wallboard. With SIMPLE.CS, ali you need to do is the follo Seal the joint between the subfloor and the gypsum board, or otheterior wall covering (see Figure 5).

Sealing this joint eliminates the necessity of having the framing crew dealan additional step while they're trying to put up the building shell. It alsomakes it possible to do the sealing work after the drywall is up ,andthe homweather-tight, This step can be postponed until just before the finish floordown.

Intersectionsf i. order to keep any air that leaks into the exterior wall out of the interiorInteriorPartition tion (or vice versa), you need to seal the area where they intersect. This ismost easily accomplished after framing is completed and the shell is insulandExteriorWall Seal the interior-wall gypsum board to the last stud in the interiortition with a continuous bead of drywall adhesive. The adhesive shrun from the subfloor to the top of the top plate.

OR. Install a length of compressible gasket between the wallboard and

last stud. The gasket can be applied ,ali at once, in advance of the dryapplica;ion, or a worker can do a room at a time ahead of the crew htming the drywall on the w;dls and ceilings (see Figures 6a _md6b).

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Intersectionsf _,__o._o.i._,_.,d_e_.h_w_d_.._,._'_o.,.InteriorPartition Seal ,he partition.wall gypsum board to file top plate of tile patti|ionand Exterior Ceiling w_,, with either a continuous bead of adhesive or a compressible gas-ket (see Figure 7). This effectively seals off the interior wall cavitiesfrom the attic or roof above.Forced-Air Heating =,_ design and ins!allation of the heatingsyslemhas a major in,pac! on, heSystems ,_,_,_f any tightening approach, A home with iu, otherwise air-tighten-velope may still have unacceptably high infiltration levels, ii"the healing sys-

tem is not designed and installed appropriately. The following guidelines willnfinhnize the negative impacl of lhe HVAC system on lhe air cxcl|mlge talc. 'Fry to gel the heating plant and the ductwork inside the heated en-

velope. That way, an), air that leaks out will still provide heat to thehome, and outside air c_utnot be pulled into the return side of the sys|em.In homes with basements this is fairly easy. In homes with crawlspaces,try rumfing a dropped soffitt in the hallway and locating the mechanic_droom in a cenlral location.

If duclwork must b? run outside the insulated shell, make sure it iswell sealed. Ductwork to be sealed includes not ordy the joints betweenlengths of duct, but also the long se_uns in metal (tucl and any crimpededges on plenum bGxes or register boots. Use a high-quality tape or ase;d_mt specifically designed for ductwork (such as AIR-LOCK; seeCaulks lr, Apl_'ndix C). Remember that metal ducl often has a thin coat-ing of oil remaining from the fabrication process. Tiffs oil must be wipedoff in order to gel any se_ding material to stick for very long. A rag wilhmineral spirits usually will do the lrick.

Design the system in such a way that the supply and return portionsare in balance. This may me_m using more returns than you nomlally do.Bedroom doors should be undercut a minimum of 3/4 inches, it"lhere is noreturn in the bedroom. Other options are louver doors or open Iransoms tothe hallway.

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Section. SIMPLE;CSAnalysisandPlanningProcedureThis step-by-step analysis and planning procedure was developed lo help coor-dinate the air-sealing effort, so that the sealing gets done in the appropriate_laces _ at the most effective and convenient stage of construction. 1I isdesigned to guide you in determining where sealing is required, when it shouldbe done, and by whom. As potential leakage sites are identified, you can usethe Air Sealing Checklist (Appendix A) lo record this intormation.To complete thi,_procedure for a specific home, you will reed floor plans andsection drawings of the building sufficient to indicate 'alipertinent informationabout the building geometry and the placement of major components. As anexample, the SIMPLE.CS analysis and planning procedure has been com-pleted on a sample Northwest horn" (see Appendix B). Recommended sealingmaterials are discussed in Appendix C.

Step 1 Identify and indicate on the floor plans and sections theexterior zone boundary (EZB) of the building.Indicating the location of the EZB may seem to be a waste of time, However,experience has shown that we are often unclear about whether a particularwall, orpart of a wall, is an "inside wall" or an "out,side wall," Differentiatingbetween the two is a critical step fi_rhomes with more than one floor level-

' two story homes, homes with basements, split levels, etc, In these cases, il iscommon to forget where the outside is in relation to the inside. For example,you might have to stop and think about areas such as stairways and commonwalls.Overhangs and cantilevers are other areas we often overlook. They usually endup getting insulated and soffitted, but our attempts at air se',ding are often notas successful as they might have been had we remembered them before thedrywall was hung.A good way to carry out this step is to use a highlighter-type marker on a set ofworking drawings 1o indicate the elements of the house that act as the dividerbetween inside and out.side, Once these are highlighted, you can see at aglance where the air barrier probably needs to be---the inside surface of tlmEZB.

Step 2 Identify on the plans and sections the locations ofdiscontinuities in the materials that wig make up theair-barrier surface of the EZB (exterior walls, floors, and ceil

The obvious locations are the joints between different building elements, suchas gypsum wallboard and plywood subflot,_. Ot_zr locations include areasst,,ch as a plywood subfloor that is actually made up of 4' x 8' pieces with.jointst,etween them at the edges. If the edges aren't sealed in some way, they canact a.sholes in the envelope.

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Step 3 Determine the type of sealing necessary and at whatstage of construction it should be done in order tomake the EZB effectively continuous.

Joints between components of the EZB tend to fall natur',dly into two groThe fiwt group requires attention before the insulators or some other buildtrade makes it impossible or difficult to do the sealiug work. Examples igroup include rimjoist are,xsin two-story or basement homes arid stairwaframing, Sometimes the actuM sealing work is not necessary at this time,an extra line of blocking or the judicious placement of required fire-blockcan make it ea,sier to do later.The plywood subfloor joints (mentioned in Step 2) are easiest to seal whifloor is being hdd, They can be sealed by applying continuous beads ofsubfloor adhesive at the butt joints on flaming members and putting a beathe bottom of the tongue before the panels are knocked together,The second group requires attention after the gypsum board h_s been placthe walls and ceilings. The board joints themselves are typically taped anfinished. The jo;.nt betweer, the wallboard and the subfloor can be caulkefoamed,

Step 4 Find and indicate on the plans and sections aliintersections of the interior partitions with the EZB.These intersections can typically be circled on the drawings with a contracolor. What we need to know is the configuration of the particular interseand ali the places it occurs, You need to remember that not 'alipartitionsup on the sections, Hopefully, enough have been drawn to characterize tconditions,This step identifies the following kinds of intersections: Interior wall to exterior wall Interior wall to exterior ceiling Balcony half-wall to exterior wall Interior wall to exterior roof/ceiling assemblies in split levels Interior second floor assembly to exterior wall in two-story and basehomes



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Step 5 Determine the type of sealing to be used for each of theintersections. Determine at what stage of construction(timing) the sealing should be done and by whom.

From the floor plan and the sections, you need to generate typical framingdelails, You can then decide on lhe placement of the gaskel, bead of caulk c_radhesive, or foam application that will se_dthe critical joint(s)in the detail.After this is detemlined you can decide whether the seal can wait until after thegypsum board is hung or if it needs attention before some other trade mattesthe seal more difficult to accomplish,'dany oi"he solutions for these air-sealing problems are 'already available ini-_"nanuals prepared for the BonneviUe Power Administration, " Olhers are,.'asily ,arrived at once the determination has been made as to where and whent_aeseal is to be made, Examples of the solutions are included in this manual(,_eeFigures 2-9 in Appendix D),Nearly as important as determining the type of sealing and the timing of theseal is designating the responsibility to a particular trade, If the conslructioncrew is not going to be handling a particular aspect of the sealing work, al Ihispoint you can start putting together lists for the subcontractors,

Step 6 Locate on the plans and sections ali areas where the EZB ispenetrated by or composed of the items in Group "A" of theAir Seating L'h__.'dist. For each item, determine the type ofseating, the timing, and the responsible trade.

Group A of the Air Sealing Checklist consists of the major stru,:tural openingsin the building envelope and other complicating framing features, Details as Iohow the air sealing is to be accomplished for each item must be detennined atthis time,These items are large enough that they typically snow up on most good sets ofbuilding plans, II's sometimes a good idea to number the item on the plan orsection so that it can be referenced in either a secondary list or a se! of detailsheets,Doors, windows, and skylights need to be considered so that the sealing isdone in concert with the inst_dlation of the units and whatever the accompa. -ing interior trim-out will be, Areas such as dropped ceilings0 sol'fitted assem-blies, _mdfurred spaces also need consideration, Should the .'drbarrier goinsi(le the volume created or should it be carried out around the outside?St`.drways and bathtubs are lroublesome spots because of their common ad-jacency to other interior walls and components (see Figure 8b), Details andideas can be worked out with work crews and subcontraclors,

! Oregon State University Extension Energy Program, BuiMer's Field Guide, Prepared for lhe Bonneville PowerAdministration, October 1990,2 Oregon State University Extension Energy Program. Residential Cmlstrt.'timl Rel"erem'e Mamlal, Prepared Ibr lilt'Bonneville Power Administration, October 1990.



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Step 7 Locate on the plans and sections ali points where the Epenetrated by the items in Group "B" of the Air SealinChecklist. For each item, determine the type of sealingtiming, and the responsible trade.

The items in Group B do not "always show up on the building plans in theitual locations, Often it is assumed that their placement will simply be carriout in conformance with applicable codes, Even though this is the case, iportant to consider the number and types of these penetrations, Often it 'ssible to minimize the number of penetrations of the EZB by consulting theappropriate subtrade or by considering alternate placement of equipment,In considering placement of equipment, you might ask the following questfor ex_unple: Is it possible to get most of the heating ductwork inside the heated en

velope? Can recessed lig!lting in an exterior ceiling be replaced with weU-desi

surface-mounted fixtures? Or Can they be placed in a soffitted area wthe air barrier between the soffitled volume and the EZB? Can the medicine cabinet be moved to an interior wall?This step is also important for determining how the chimneys, flues, andplumbing stacks will be sealed, Typically, these areas are not sealedsuccessfully with foams, It's at this ,,,lagethat alternatives can be discussed',roddecided on, A common cause of failure in air-sealing attempts is nothaving the fight material on the job at the fight time, For example, if youusing a piece of EPDM sheet as the air-barrier collar to be sht._d over pling stacks where they penetrate top plates, you ide',d.lyshould have them osite for the plumber to slip on the pipe when it goes through the plate (seeure 8a), You can easily staple one near the entry point of each drain linevent stack so that the plumbing sub can put it over the pipe for sealing atdate,

qten 8 For the items in Group "C" of the Air Sealing CheckliIt.,,.f IIb_ IqlJ determine the type of sealing, the timing, and the resptrade.The items in Group C tend to be the smaller holes in the house, Typicallythese items 'also ,areonly schematically indicated on the drawings, it'at ali(plumbing runs are ntrely shown for example), However, the same decisioneed to be made for these items as those made for the penetrations alreadyaddressed, Consider the typical cases and decide accordingly,An important thing to keep in mind is that holes in the exterior framing, wwire and water-supply pipes run, do not need to be sealed, They are a cononly when the holes occur at the cormection between inside and outside, t"through" the EZB,Some of these items, like others in Groups A and B, may have more thtuJtrade or subconfractor as a possible person to do the sealing, The approprchoice depends on the builders'knowledge ot' the capabilities and costs otheir subs and their crew members,



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Step 9 _o_,.d_ in the contracts for the appropriate trades the itemsfrom the checklist they are responsible for. Include a description of the type of sealing desired. Indicate by wha! point inthe construction pl'ocess tile sealing slmll be completed foreach item.

The decision reg,'u-ding the responsible trade has already been made _uldentered on the Air Sealing Checklist, Therefore, it's now relatively simple toexlract an individual iis! for each of the subcontractors with sealing respon-sibilities.At ttli_point, it may make sense to rntxtit_the lisl. For exmuple, you mighldecide to go wfih a single air-sealing subcontraclor rather tl-l_ma number ofsubtrades. Or you may decide to simply have your own crew take on ltle job,since there is usually a crew member on site even when the other subs are there,The list cernbe refined by considering questions such t,:, the following: Are loo many trades involved? ts the plumber doing only two things? Will the particular subs do a good .jobor would lhey rather just Ix,respon-sible ibr lheir usual duties? Who should be responsible for providing the sealing materials'/An imporl,'mt issue to ch'u'ify with the svbcontractors is a( what point the se,'d-ing should be completed for their particultu' item(s), If construction isdehtyedbecause the work of one sub isn't finished in lintc, you will need Io considerways to gel back on schedule,

Step 10 Determine if blower door testing will be required and,if so, at what point.One of Ihe only ways to actu_dly delermine the tightness of conslruclion is I_yblower door lesting the home. This lesting is a fin_dexam, so Io s peak. 1!usually occurs when ali air sealing has been completed and acls as lhcmeasured result for that home. A large tim and support-bracket assembly istempor_uily hlst_dled in _mopen door ofthe home. While Ihe fan is operaled alvttrious speeds, a series of pressure and air-llow nleastJremerlls are made,These data can be analyzed to give an indication of the Iolal leakage _u'eaoflhc home,An alternative is to engage an _dr-sealing or fan door contractor to do a prelimi-nary diagnostic test on the home while many of the seals are still accessible--for exlunple, before lhc allic insulation is blown, or before carpet,s, pads andbaseboards are inslalled. While the home is depressurized by the blower d_or,il is easy Io idenlify the areas where air is rushing in. They can be identifiedby means oi"a small smoke-producing device (a "smoke-stick") or even yourhand. This approach allows you to lest and improve the qualily of the scalingw_rk,



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AppendixAAir Sealin9Checklist


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U')

03

r._Z

r,jii0LUr,j _.

rG ........... _ i03IiiZ

wii(5d d_ g_g_._ E

03

!_l I- n '_ _ "_ _ " '- i _ -_0 ml n _ _ , .=_ "_ _, ._ = _ _ =

"1- rr'l E:)n" 0 _ i '" ._ = __._ o _l ,- _-Ali I.eakalleControl ManlJ;_l


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/')UJ

" 1,iii

l,J ZZ"' i,,0

o) = _0) _) '.m _ . c:: _

,-- _ t" ,

a._. o ,- e ,.::_" , rna- _g -o ,-w '_ ,_ _ _: ._o._ _" '_'_ 0 _,.-

.... ._ _-- ,-- __ ..-_o _ __ ,_ z :_.:__ _ oo )__ _ ....0

A-2AI__akag_ontrolManual


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AppendixBCompletedSIMPLE,CSAnalysisanPlanning Procedurefor SamplHome


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Appendix.Comp!etedSIMPLDCSnalystsndPlanningProcedureorSampleHome

OutlineofSIMPLE.CS Step1 ,d_.,.'yid i,ldicate on the llot, r phmsmid sections theexzone boundary (EZ,B) of tl_ builcting,AnalysisandPlanningProcedure Step2 _d_.,..y,,,,_,__,,,,,_..,,_,_;_,_,,,,_.,_o_.,.,,,,_,,,ill the materials that will make up the surface of the EZB (ewalls, floors, mid ceilings),

Step 3 Detem,ine the type of settling necessary ,u,d at what stageconstruction it should be done in order to make the EZBeffectively continuous,

Step 4 vi,,d and indicate on the phms tmdsectlons ali intersectionsthe interior partitions with the EZB,Step 5 Do,om,i._ the tel;= ,,fselding to be used for eat.i, .t'ttv:intersections, Determine at what stage of construct!t t_(thnthe sealing should be dotve lind by whom,Step 6 Co_.,e on the plans and sections ali areas where the EZB ipenetrated by or composed of the items in Group "A" of th

Air Sealing Checklist, For each item, determine the type osealing, the timing, and the responsible trade,

Step 7 i.oc.,_ on the plates ,rod sections ali points where the EZI3, penetrated by the items in Group "B" of the Air Sealing, Checklist, For each item, detennine the type oi' sealing, fixtiming, and the responsible trade,

Step 8 F,,r the items in Group "C" oi'the Air Sealing Checklist,cletem_ine the type of sealing, the liming, at_l tlw responsibStep 9 Include in the contracts for the aptm, priate trades the itemstile checklist they are responsible for, lnclucle a dcscriptitm

the type of seiding desired and indicate by what lmilll irl thctmslnmclion process lhc sealing shall tw oomph, lt,d,

Step 10 t,_:,_,,,,i,,,_H,,w_,.,I,,,,_,,,._,i,,_i,,,,,.,.,,,,i,_,,!,,,,I,,.what poilzt,

Ah-l.eakagoorlholMarmal6-1


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Main Levelili;:iiiii!_::iiii_!:::_i_;

0 2 4 6 8 Feetii:i:/.i;:',::_,!:,::ii!_i_:,_;,ii;_;i!tep 1:Ident fy the E,Z,B,

Step 2: Plywood Subfloor Joints,Drywall/Subfloor Joi_ts, DrywallJointsStep 4: Intersections-- See Details

B-2Air-LeakageontrolMa.ual


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Den 5a Utility/. " I ., ,\

/Figure 6a //

/

',,


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I

Figure 5Section:::::::::::::::::::::

0 2 4 6 8 Feet

i_iiiiii',_iiii':ii:._i;iitep 1: denti-f_ the E.Z.5.Step 2: Pywood Subf oor Joints,Drywall/C,ubf oor Joints, DrywallJoints

..Step 4: Intersections-- See Detailsil-4 Air-LeakageontrolManuaI


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AppendixCSealingMaterials


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Appendix. SealingMaterialsFive types of sealing materials are discussed in this appendix: adhesives,caulks, gaskets, foams, and sheet materials,

AdhesivesUses Adhesives are already in common use on nearly ,alijob sites. They are c()m.

monly used for the joints in plywood subfloors ,andfor sealing the drywall toframing members, such as top or bottom plates. They can be used for air se,'ding a variety of connections,Adhesives are most successful when used between the surfaces of the memberbeing connected, They adequately fill and span gaps of 1/8 inch or less, Inpractice, what they effectively do is ensure contact between the pieces "gluedtogether." They do not peffoma well when used as a caulk for comer joints owhere there will be di,fferential movement of the two n|embers being joined.The purpose of an adhesive is to bond things together. If one member moves,the adhesive and its associated fasteners try to bring the other member with itThey are not intended to be flexible,There are many adequate products on the market, You should select brandsand types that are suited for the intended applications, For example, ifplywood is to be sealed as a subfloor, the adhesive should be designed forpotentially wet and cold job conditions,

AdhesiveProducts Available products include the following:STA-STUCK - 400Manufactured by Specialty Chemicals Co., Elk Grove Village, IL 60007;312-766-2400.HENRY 113 Drywall Stud MasticManufactured by The WW Henry Company, Huntington Park, CA 90255',213-583-4961.LUMBERLOCK Ali Weather Construction AdhesiveManufactured by Miracle Adhesives Corp., BeUmore, NY 11710.PL200 and PLS00 Construction AdhesivesManufactured by ChemRex Inc., Contech Brands, Minneapolis, MN 53435.

Ah-I eak,_rJr_;,onl=olMzniml C,-Iv


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CaulksUses Unlike adhesives, caulks are usually fornmlated lo carry out two lasks--tc_ sea

itself to other materials and to fill space, They work best in holes _mdgaps belween I/8 inch and 1/4 inch, Somewhal larger gaps c_mbe filled, bul they mayrequire successive applications, The ureth,'ule products have greater success af'dling lhe larger gaps, Producls with superior l)ertbrmance, in general, art, liltsilicones, ureth_mes, and the newer "siliconized" acrylics. These waler-resistant products have good elastic characteristics and good adhesion to moslbuilding materizds, They also tend to resist shrinkage.Common joints fbr which caulks may be the se_ of choice includeIhe gap between the gypsum w',dlboard and a subfloor, the cracks around door _mdwin-dow trim, trod aJound cutouts in gypsum board for electrical boxes.

CaulkProducts Available products include the following:AIR-LOCK, Water-Based Duct SealantManufactured by RectorSeal Corp,, 2830 Produce Row, Houston, TX 77023;800-231-3345.MO 35 Acrylic Rubber Sealant with SiliconeManufactured by Mecklenburg-Duncan, P.O, Box 25188, Oklahoma City, eK73125; 800-654-8454.MAGIC SEAL 25 Year, Slliconized Acrylic LatexManufactured by Magic Seal Corp., St. Louis, MO 63043.SONOLASTIC NP-1, Urethane SealantManufactured by Solmebom Building Products, a division of Rexnord Chemi-cal Products Inc,, Minneapolis, MN 55435; 612-835-3434,SIKAFI.,EX lA, Urethane SealantManufactured by SIKA Corp., Construction Products Division, P,O. Box 297,Lyndhurst, NJ 07071; 201-933-8800,

GasketsUses Gaskets serve much the same space-filling tunction a,scaulks, but they also ar

easy to use between maten'als, as the adhesives are used, They ,arepreformedelastomeric materials that may or may not have an adhesive backing. Theirprimary purpose is to provide air-barrier continuity in the hidden seams be-tween materials.Gaskets are commonly available in the tiron of tapes, backer rods, and otherprofiles that may have specific application. They are typically made fromEPDM, polyethylenes, neoprenes, or other plastics.Joints for which gaskets seem especially suited are the drywall to wood-framing connections at floors, w',dls, and ceilings. They need to becompressed in order to function, because they have no perm_ment adhesion tothe surfaces they lie between. Because of their ability to be compressed ,andreturn to their original dimension, they are appropriate to use when largeamounts of joint movement are expected. Another advantage of gaskels istheir ability to Idiow one component Io slide slowly by another while mainlaining contact.


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GasketProducts Available products include the following:ADA GASKET, EPDM rubber gasketing (specifically designed forADA.type construction)Distributed by Resource Conservation Technology, 2633 North' Calvert St,, Baltimore, MD 21218; 301-366-1146."P" SINp Weatherstrip, EPDM Rubber, Self adhesiveDistributed by Whole Energy & Hardware, 103 Peary Rd., Bay 1, Chaska,MN 55318; 1-800-544.2986.V 770 NORSEAL, Vinyl foam tapeManufactured by NORTON Sealants and Performance Plastics, 1377 9rh AvSan Francisco, CA 94122; 415-923-1476,SURE SEAL and ULTRA SEAL, Saturated foam gasketsDistributed by DENARCO SMes Company, Elkhart, IN 46515; 219-294-760

FoamsUses Expanding foams are most commonly used on the site tosealopeningslargethan 1/'2inch, They are also applied to penetrations like plumbing supply lin

and telephone and electrical wiring, Foams are usually either "triple" expaning or only slightly expanding, The expanding formulations have more ap.plications for large holes, though some care is required when filling a hole tis also deep. The nonexpanding foams seem to work well where there is a gthat cannot be caulked successfully, such as the shim space around windows',roddoors._le foams come in canisters ranging in size fl'om 12 ounces to 10 pounds.They are available with a simple throw-away, one-time spout or with a hoseat d reusable applicator tip. Another application tool is a type of applicator-gun assembly that allows for the adjustment of the foam bead sire.

SourcesofFoamProducts Possible sources of foam products include the following:Various foams and gun-type systemsWhole Energy & Hardware, 103 Peavy Rd., Bay 1, Chaska, MN 55318;800-544-2986 or 612-448-1668.HILTI Fastening Systems, Foam and applicator gun systemsHILTI Fastening Systems, 3487 NW Yeon Ave., Portland, OR 97201',503-227-6323.CONVENIENCE Products, Touch'n Seal Instant Sealant, Foams andsystemsConvenience Products Inc., 4205 Forest Park Blvd., St. Louis, MO 63108',314-535-6226.FOMO Products Inc., Foam and applicator systemsFOMO Products Inc., 2775 BarberRd., P.O. Box 1078, Norton, OH 44321;216-753-4585.PURFIL IG, an interesting new product which uses CFC-142B as the expasion agent. (According to advertising information, this chemic_d is 95 perceless damaging to the ozone layer than conventional CFCs.) Contacl Peter CIon atTodol Products, Inc., 20 Charles St,, Nafick, MA 01760; 508-879-174

A.!!-Le_k_n.o3_.n.r;tro!_n,__!-_


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SheetMaterialsUses Some penetrations, such a,splumbing drains and vents, are not effectively

sealed with caulks or fotmis, In places where tile holes _u'eirreguhu" or there isno backing to foam ag_dnst, even a se',d that looks good at the time of applica-tion may fail over time as a result of movement or shrinkage axldexpansion,In these cases, the answer may be to use a small sheet of elasttc material with ahole cut out for the penetration, The hole in the sheet will remain snug aroundthe pipe and the sheet can be caulked and stapled to the framing,Pieces of rubber can be cut from old truck inner tubes, Tire rubber is about 1/8inch thick or greater and can be cut into 6"x 6" pieces or whatever serves tt_.,purpose, If the inner tube material is too small or unavailable, sheet EPDM orneoprene are both possible alternatives for rids type of application, Lm'gepieces of sheet EPDM have been used to help seal off the t_netration of largeducts through blocking or subfloors, Be sure to maintain adequate fire-blocking,

SourcesfSheetMaterials Possible sources of sheet materi',d include the following:Resource Conservation Technology hie,, 2633 North Qdvert St, , Baltimore,MD 21218; 301-366-1146,Whole Energy & Hardware, 103 Peavy Rd,, Bay 1, Chaska, MN 553].8;1-800-544-2986,

C.i AIr-I AnkaraCn.nJ.r_F,am.!_!


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Appendix/,1Detail Drawings


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Figure1. Typical"ADA"CeilingDetail

Compress hie Gaskets(Typical)I .

I _ -- I i i_ll i illll-- -- iii IIll I I ! III III '"

Second Floor Structure

.........................ontinuous Air 5artier Surface

AI. I .~_ . .. .M,, L_ G_,ii|iOi Mu,


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Figure2. IntersectionofinteriorandExteriorWall

:-:.:._x;;;............__...._.__...... Rterior Wall;_-;-.-} : "2;:--_ Gasket or Caull-_ 5arrler F_ffectivelyContinuous

:a__ interior Partition]

nul i i _t "

_ ........ "".............................allboamdas Air 5artier

U-_, Air LeakageControlMuvl_i


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Figure3. "ADA"Wall Sectionat FirstandSecondFloors.................................:..................._ ,,. Gaskets

................. ',i

:.2)

__,_,;.,_,i-",.-"_,-'.::_ '.;i, 1.... ,, Second Floor Structure_..-'_' ,

::z_-:':_-__--:__- :__- Gaskets

................-_l}:i _ MaimFloor Structure

AirLeakageontlolMa


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Figure4. SIMPLE.CSCeilingatSecondFloorLevel

i........,.ii. ....

-4AllLeakageontrolMailiml


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Figure5. SIMPLE.CSCeilingat ExteriorWall/i!FloorJoint

..... ........ 9. JoistNote: Thisjointworks best if a gapof about 1/8"-,1/4" iseft between the

III li gypsum wallboard"] / and the subf ooc- ..AirLeakageontrola


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Figure6a. Intersectionof InteriorandExteriorWall(Type1)

_1 t - ior Wall

". Backer Mastic or Gasket Either at

Backer or at Stud (Not..........._ ....... Requiredat Both Locations)

interior PartitionAirLeakageControtManual


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Figure6b. IntersectionofInteriorandExteriorWall(Xl_pe2)Type 2. Intersection With a Corner

i i __ -- plJ L

c_--+ / ,' 't i t i _ i t i t], _,it/ ',,,\/tit -- EteriorWall_,,V ',! ',Ili'

:___------_j_-7-- [Jrywall Clips

, i!! '- _ .. --Mastic or Gasket Here

.... , Interior Partition

_____.- , |AirLeakageontrola


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,Figure7. IntersectionfInteriorWall andExteriorCeiling


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Figure8a. SealingatPlumbingPenetrationsPlumbing Penetrations

I.

]_ L _T .... ' Ii J- ......................... Unheated Attic,,

interior PlumbimgWall

5athroom1l Caulk or Foam Here

j.-

._ Unheated Crawl Spaceor 5asement

$ 'il- zJ ...._ Rubber Gasket, Cut Hole

__ ,J Just Smaller Than PipeSeaiant 5etweenGasket and Plate I IStaple.

Plumbing \_nt ............................................................

Air LeakageControlManu


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Figure8b, SealingforBathtubat SubfloorCutoutBathtub Drain Connection Hole

5locking with Hole DrilledJ for Supply Pipes (Foam atPenetration)

Block Between Joists

Seal Piece of Plywood to5locking and to Sides ofJoistsFoam or Caulk Drain Pipe

D-lO AirLeakageControlManual


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Figure9. SealingElectricalPenetrationsElectric Wiring Details

Seal Penetrations withi, Expanding Foam

/ J

,,

Unheated Crawl Space./, or Basement

,/

/

For Exterior Walls

i _ li ii

Out et in 5o i-_ .."Foam Out et Plate Gasket

/_

Outlet BoxOut et Cover Plate CEpandedVew)

Air LeakageContlol Manu


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i


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Documents

Air-Leakage Control Manual