S i g m a ® i i B u i l d S y S t e m :

t e C H n i C a ld e t a i l Sc l o s e d p A n e l s o l u t i o n s

Sigma® ii Build SyStem:

t e C H n i C a ld e t a i l S

2

The team at Stewart Milne Timber Systems is committed to providing the highest level of support and advice at all stages of your project. In particular we can add real value when we work alongside your team during the early stages of a projects development.

Working as an integral part of the project

design team enables us to add maximum

value at concept and detailed design

stages where we can offer advice on

aspects such as:

• Appropriate and cost effective

specifications

• Value engineering

• Enhanced buildability

• Waste reduction

• Designing out risk

The information contained in this

technical guide will assist you in selecting

the right products for your project. We

would be happy to take you through our

range of products and recommend those

that most suit your requirements.

closed pAnel solutions

3

siGMA® ii build systeMproduct specificAtion

siGMA® ii build systeM

product specificAtion

External walls (U-value) 0.25 0.22 0.20 0.17 0.15 0.13 0.12 0.10

External wall (product code) 89SP 89SL 140SP 140SL 195CP 195CL 235CP 235CL

Stud type 89mm Solid 140mm Solid 195mm C-stud 235mm C-stud

Plasterboard finish (Type A - site fitted)

15mm Foil backed

plasterboard

35mm Thermal laminate

plasterboard

15mm Foil backed

plasterboard

35mm Thermal laminate

plasterboard

15mm Foil backed

plasterboard

35mm Thermal laminate

plasterboard

15mm Foil backed

plasterboard

35mm Thermal laminate

plasterboard

Service cavity 25mm Batten - factory fitted

Air tightness 5.00 – 3.00 3.00 – 1.50

Thermal bridging (Y-value) 0.08 – 0.04 0.06 – 0.02

External wall - fire rating - completed building 30 or 60 minutes

External wall - fire rating - during build Optional fire protection - UKTFA fire separation - type B & C classification

Party walls (U-value) 0.00 (fully filled and effectively edge sealed)

Ground floors (U-value range) 0.18 – 0.09

Roof (U-value range) 0.20 – 0.10

Structural panel thickness (exc batten)

107mm 158mm 213mm 253mm

Foundation blockwork width 100mm 140mm 215mm 250mm

Foundation strip footing width 550mm 600mm 650mm 700mm

O/all width 102mm brickwork and 50mm cavity

299mm 319mm 350mm 370mm 405mm 425mm 445mm 465mm

O/all width - 30mm lightweight cladding and 50mm cavity

227mm 247mm 278mm 298mm 333mm 353mm 373mm 393mm

Overall height, buildings up to Up to 4 Storey

Notes: U-values presented are calculated for brickwork cladding. U-values vary depending external cladding finishes. Overall wall thickness is calculated based on 15mm plasterboard finish to achieve 30 minute fire protection. Width varies when using thermal laminate and 60 minute fire requirements. Foundation strip footing width assumes nominal 150mm toe projection either side and 50mm cavity with 100mm masonry cladding, to comply with NHBC standards.

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“psi” vAlues (lineAr therMAl bridGinG)

description Certification No.

C Psi ValueSigma® II

Build System

ACD (Accredited

details)Improvement

ƒ Temp. Factor

Sigma® II Build System

External corner C4TM-573 0.045 0.090 50.0% 0.906

Internal corner C4TM-574 -0.040 -0.090 55.6% 0.974

Party wall to external wall C4TM-575 0.065 0.060 -8.3% 0.943

Ground floor, beam and block parallel, 150mm insulation above C4TM-576 0.034 0.160 79.0% 0.935

Ground floor, beam and block perpendicular, 150mm insulation above C4TM-577 0.030 0.160 81.6% 0.934

Party wall junction (beam and block floor) C4TM-578 0.054 0.160 66.0% 0.985

Intermediate floor (houses) C4TM-579 0.042 0.070 40.0% 0.960

Intermediate floor (flats) C4TM-580 0.090 0.140 35.7% 0.959

Typical eaves detail (truss) C4TM-581 0.049 0.060 18.8% 0.935

Typical gable detail (truss) C4TM-582 0.050 0.240 79.0% 0.924

Party head, top of ceiling insulation C4TM-726 0.039 0.240 83.8% 0.946

Window head – insulated reveal, lintel in floor and firestop C4TM-682 0.022 0.500 95.6% 0.954

Window head – lintel in wall, insulated reveal and firestop C4TM-146 0.046 0.500 90.8% 0.882

Window jamb – insulated reveal and firestop C4TM-686 0.029 0.050 42.0% 0.950

Window cill – PVC extension, insulated reveal and firestop C4TM-684 0.026 0.040 35.0% 0.952

For projects using Sigma® II Build System 0.15 U-value, 195mm, C-studs and 0.031 W/mk thermal, conductivity EPS insulation.

Notes: Calculations performed in accordance with ENISO 10211 - 2007 and BRE information paper IP 1/06, BR497 and BR443. Temperature factory ‘f’ exceeds 0.7 in compliance with E and W Building Regulations, Part C Section 5.36b and BRE IPI7/01, Section 4.1. PSI value is the calculated heat loss between the junction of two elements.

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The table below provides examples of Y-value calculations using Sigma® II Build System.

y-vAlue cAlculAtions (An exAMple of overAll therMAl bridGinG for A house)

typicAl 3 bedrooM end terrAce two storey hoMe (Approx 82M2)

Junction description Psi Length Heat Loss

Lintel below mid floor 0.029 5.3 0.15

Lintel below roof 0.046 4.35 0.20

Cill 0.026 9.65 0.25

Jamb 0.029 22.7 0.66

Ground floor (Parallel) beam and block, 150mm insulation above

0.034 9.7 0.33

Ground floor (Perpendicular) beam and block, 50mm insulation above

0.030 8.42 0.25

Intermediate floor/external wall 0.042 18.12 0.76

Eaves (Truss) 0.049 9.7 0.48

Gable (Truss) 0.050 8.42 0.42

External corner 0.045 10.12 0.46

Party wall/external wall 0.065 10.12 0.66

Party wall/ground floor 0.054 8.42 0.45

Party wall/ceiling (truss) 0.039 8.42 0.32

totAl lineAr heAt loss 5.39

totAl heAt loss surfAce AreA 175.50

y-vAlue 0.031

stAndArd Acd defAult 0.080

Notes: Example based on 0.15 U-value Sigma® II Build System, using 195 C stud and 0.031 W/mK thermal conductivity EPS insulation. Each 0.01 improvement in Y-value can contribute up to 1% saving in SAP rating. Y Value is the summation of the total heat loss across all junctions in the building.

The Sigma® II Build System offers a 5% thermal bridging improvement over the SAP default. This could mean a change in windows from triple glazing to double glazing or an alternative non mechanical ventilation system, both of which saves significant cost.

3 bed end terrAce(Approx 77M2)

2010 csh level 3 solution projected 2013 csh level 4 solution

MVHR MEV Natural MVHR MEV Natural

Orientation Not solar dependantNot solar

dependantNot solar

dependantNot solar

dependantNot solar

dependantNot solar

dependant

U - value walls 0.25 0.20 0.17 0.17 0.12 0.15

U - value party wall 0.00 0.00 0.00 0.00 0.00 0.00

U - value floors 0.16 0.16 0.16 0.10 0.08 0.10

U - value roof 0.13 0.13 0.13 0.08 0.08 0.10

Window whole U-value and glass G-value

Double glazing 1.20, 0.30

Double glazing 1.20, 0.30

Double glazing 1.2, 0.30

Double glazing 1.0, 0.41

Triple glazing 0.8, 0.41

Triple glazing 0.8, 0.41

Patio/French doors Double glazing 1.20, 0.30Double glazing

1.20, 0.30Double glazing

1.2, 0.30Double glazing

1.0, 0.41Triple glazing

0.8, 0.41Triple glazing

0.8, 0.41

External doors 1.50 1.00 1.50 1.00 0.80 0.80

Thermal bridging (Y-value) 0.08 0.08 0.06 0.03 0.03 0.03

Airtightness 3.00 4.00 5.00 3.00 2.50 5.00

VentilationMVHR

(SFP 0.52, Eff 91%)

MEV (SFP 0.21) Natural

MVHR (SFP 0.52 and

Eff 91%)

MEV (SFP = 0.21) Natural

Combi boiler Combi (Eff 89%) on/off control system

Controls Time/temp zone control, delayed start and load compensator

Low energy lighting 30% 30% 30% 100% 100% 100%

Hot water storage insulation N/A N/A N/A N/A N/A N/A

SAP Q tech 1 N/A Flue gas heat recovery N/A N/AFlue gas heat

recovery Flue gas heat

recovery

SAP Q tech 2 N/A Waste water heat recovery N/A N/AWaste water

heat recovery Waste water

heat recovery

Dwelling emission rate (DER) (Kg CO2/m

2) 18.92 18.93 18.50 14.36 14.33 13.96

Target emission rate (TER) (Kg CO2/m

2) 19.17 19.17 19.17 19.17 19.17 19.17

% Dwelling emission rate (DER): Target emission rate (TER) Improvement

1.31% 1.25% 3.50% 25.09% 25.25% 27.19%

Fabric energy efficiency standard (FEES) (KWh/m2/yr) 48.6 47.0 47.7 35.4 30.1 34.7

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Notes: SAP Calculations run on: NHER SAP 2009, Plan Assessor v5.4.0.49 software using English building regulations MEV: Mechanical extract ventilation system. MVHR: Mechanical ventilation heat recovery system. CSH: Code for Suitable Homes SFP: Specific Fan Power. Eff: Efficiency Rating

The table below provides example SAP specifications for 2010 and projected 2013 energy compliance using Sigma® II Build System, adopting 3 alternative ventilation strategies. Naturally vented solutions offer a cost effective compliant option without complex mechanical ventilation and potential customer maintenance issues.

sAp coMpliAnce: fAbric first

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floor, ceilinG And roof cAssette

construction joist typeperiMeter/ AreA rAtio

joist depth (MM)

220 235 300 350

u-vAlues

Joist type and depth, relevant to building footprint.

Solid timber

0.4 0.14 0.13 N/A N/A

0.7 0.15 0.14 N/A N/A

0.9 0.15 0.14 N/A N/A

I-Beam

0.4 0.12 0.12 0.10 0.09

0.7 0.13 0.12 0.10 0.09

0.9 0.13 0.13 0.10 0.09

Metal web

0.4 0.17 0.17 0.15 0.13

0.7 0.18 0.17 0.15 0.13

0.9 0.18 0.18 0.15 0.13

U-values – Suspended cassettes with ventilated air space below and appropriate level access detailing.

construction joist type

joist depth (MM)

220 235 300 350

u-vAlues

Joist type and depth

Solid timber 0.17 0.16 N/A N/A

I-Beam 0.15 0.14 0.11 0.10

Metal web 0.20 0.19 0.16 0.14

U-values – Cold roof, insulation at ceiling level and spanning wall head to wall head.

Note: Joists at 400mm centres with insulation thermal conductivity 0.032 W/mK

construction rAfter type

rAfter depth (MM)

220 235 300 350

u-vAlues

Rafter type and depth

Solid timber 0.16 0.15 N/A N/A

I-Beam 0.15 0.14 0.11 0.09

Metal web 0.18 0.17 0.14 0.12

Note: Joists at 400mm centres with Insulation thermal conductivity 0.032 W/mK. Soil conductivity at 1.5 W/mK . Ventilated air space below and 300mm thick perimeter masonry at 0.35 W/mK.

U-values – Warm roof, insulation at rafter level, inclined cassettes and supported on purlins.

Notes: Rafters at 600mm centres with insulation thermal conductivity 0.032 W/mK U-values for conventional trussed roofs and concrete ground floors are available. Please ask for details.

Ground floor cAssettes

roof cAssettes

ceil inG cAssettes

The Sigma® II Build System offers the following range of floor, ceiling and roof cassette values.

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construction detAilssolid stud – 140MM stud shown

• The following options are available; suspended slab, ground bearing slab and timber suspended floor

• It is recommended that the insulation is fitted above the slab to achieve the best psi values.

• Panel junctions are supplied with pre-fitted foam air seals, as required.

• Service battens are pre-fitted.

• Cassettes are supplied pre-fitted with air membrane wrapped around ends and have pre-insulated perimeters.

• Floor cassette options are: Solid timber, I-beam or open web joists.

• This conforms to MIMA design guidance and provides full fill and effective edge sealing.

• Option for OSB sheathing for racking and secure by design can be accommodated.

• 89mm twin leaf party wall Robust Detail, E-WT-1 or E-WT-2.

• For air tightness less than 3, it is recommended to use an air membrane to face of studs (as shown).

A Sigma® II solid stud external wall panel

b 38x140mm soleplate on DPC fixed to top of slab

c Chipboard floating floor on insulation on beam and block floor

d Air-tight foam seal below soleplate wall panel and top of DPM on floor

A Sigma® II solid stud external wall panel

b Foam seals pre-fitted to end of wall panel

c Junction studs pre-fitted to wall panel for site fixings

A Sigma® II solid stud external wall panel

b Air-tight membrane pre-fitted to end of floor panels

c External perimeter of floor panel pre-fitted with insulation

d Foam seals pre-fitted to head and foot of wall panel

A Sigma® II solid stud external wall panel

b 50x300mm insulated cavity barrier to end of party wall cavity

c Air-tight membrane fitted on-site, subject to performance required

d 50 – 70mm fibre insulation batt

e 9mm OSB pre-fitted to one leaf of party wall only as required structurally or for secure by design

f Insulation fitted between studs by contractors

Ground floor detAil interMediAte floor detAil

externAl corner detAil pArty wAll to externAl wAll detAil

A

A

A

A

D

B

BC

C

CB

D

A

C

The Sigma® II Build System has a library of over 150 construction details produced for easy integration into architectural design information. Common construction illustrations are:

D

F

BE

MIMA – Mineral Insulation Manufacturing Association

9

• For air tightness less than 3, it is recommended to use an air barrier membrane to underside of trusses.

• For air tightness of greater than 3, boarding of ceilings and edge sealant is normally sufficient.

• An option of a ceiling cassette is recommended where early weather protection, speed or room in roof design considerations are important, removing the need for an air barrier membrane.

• It is recommended to use insulated flexy fire barriers in conjunction with thermal laminate plasterboard reveals, to maximise psi values.

• An option to factory fit windows with pre-fitted air seals is available.

A Timber lintels as structurally required within wall panel

b Insulated cavity barrier to window perimeter

c Insulated plasterboard to soffit reveal

d Window sealed into timber frame wall panel with air-tight tapes

e Insulated plasterboard below window sill

f Insulated cavity barrier to window perimeter

G Solid stud external wall panel

A Additional insulation above ceiling cassette (as required), or full depth cassette to suit U-value

b 0.15 U-value ceiling cassette

c Foam seals pre-fitted to top of wall panel

d Sigma® II solid stud external wall panel

A Air-tight membrane and service void fitted on site, subject to performance required

b Glasswool insulation between trusses to suit U-value, lapped over wall head as shown

c Sigma® II solid stud external wall panel

A Insulated cavity barrier to window perimeter

b Thermal laminate plasterboard to reveal

c Window sealed into timber frame wall panel with air-tight tapes

d Sigma® II solid stud external wall panel

eAves detAil with ceil inG cAssette eAves detAil without ceil inG cAssette

window cill And l intel detAil window reveAl detAil

A

A

A

A

B B

B B

C

C

C

C

D

D

EF

G

D

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construction detAilsc-stud – 195MM stud shown

• Panels are designed to lock into soleplates, to reduce cross grain shrinkage, improve stability and aid air tightness.

• The following options are available; suspended slab, ground bearing slab and timber suspended floor.

• It is recommended that the insulation is fitted above the slab to achieve the best psi values.

• Panel junctions are supplied with the pre-fitted foam air seals or air tape site fitted, as required.

• C-stud reduces the amount of solid wood contact and provides a better psi value.

• Service battens are pre-fitted.

• Panels are designed to lock into soleplates, to reduce cross grain shrinkage, improve stability and aid air tightness.

• Cassettes are supplied pre-fitted with air membrane wrapped around ends and have pre-insulated perimeters.

• Floor cassette options are: Solid timber, I-beam or open web joists.

• C-stud flanking detail is undergoing Robust Detail accreditation and has secured Stage 1 candidate detail status.

• This conforms to MIMA design guidance and provides full fill and effective edge sealing.

• Option for OSB sheathing for racking and secure by design can be accommodated.

• For air tightness less than 3, it is recommended to use an air membrane to face of studs (as shown).

A Sigma® II C-stud external wall panel

b 38x63mm soleplate on DPC fixed to top of slab

c Chipboard floating floor on insulation on beam and block floor

d Air-tight foam seal below wall panel and top of DPM on floor

A Sigma® II C-stud external wall panel

b Foam seals pre-fitted to end of wall panel

c Junction studs pre-fitted to wall panel for site fixings

d Service battens at corners, are site fitted to allow panel connection

A Sigma® II C-stud external wall panel

b Air-tight membrane pre-fitted to end of floor panels

c External perimeter of floor panel pre-fitted with insulation

d Foam seals pre-fitted to top and bottom of wall panel

A Sigma® Build System II C-stud external wall panel

b 50x300mm insulated cavity barrier to end of party wall cavity

c Air-tight membrane fitted on-site, subject to performance required

d 50 – 70mm fibre insulation batt

e 9mm OSB pre-fitted to one leaf of party wall only as required structurally /or for secure by design

f Insulation fitted between studs by contractors

Ground floor detAil interMediAte floor detAil

externAl corner detAil pArty wAll to externAl wAll detAil

A

A

A

D

B

BC

C

D

CB

D

D

A

C

The Sigma® II Build System has a library of over 150 construction details produced for easy integration into architectural design information. Common construction illustrations are:

BE

D

F

MIMA – Mineral Insulation Manufacturing Association

11

• Panels are designed to allow a head binder insert, reduce cross grain shrinkage and assist air tightness.

• For air tightness less than 3, it is recommended to use an air barrier membrane to underside of trusses.

• For air tightness of greater than 3, boarding of ceilings and edge sealant is normally sufficient.

• An option of a ceiling cassette is recommended where early weather protection, speed or room in roof design considerations are important, removing the need for an air barrier membrane.

• C-stud reduces the amount of solid wood contact and provides a better psi value.

• It is recommended to use insulated cavity barriers in conjunction with thermal laminate plasterboard reveals, to maximise psi values.

• An option to factory fit windows with pre-fitted air seals is available.

A Lintels over openings within mid floor above

b Insulated cavity barrier to window perimeter

c Insulated plasterboard to soffit reveal

d Window sealed into timber frame wall panel with air-tight tapes

e Insulated plasterboard below window sill

f Insulated cavity barrier to window perimeter

G C-stud external wall panel

A Additional insulation above ceiling cassette (as required), or full depth cassette to suit U-value

b 0.15 U-value ceiling cassette

c Foam seals pre-fitted to top of wall panel

d Sigma® II C-stud external wall panel

A Air-tight membrane and service void fitted on site, subject to performance required

b Glasswool insulation between trusses to suit U-value, lapped over wall head as shown

c Sigma® II C-stud external wall panel

A Insulated cavity barrier to window perimeter

b Insulated thermal laminate plasterboard to reveal

c Window sealed into timber frame wall panel with air-tight tapes

d Sigma® II C-stud external wall panel

eAves detAil with ceil inG cAssette eAves detAil without ceil inG cAssette

window cill And l intel detAil window reveAl detAil

A

A

A

A

BB

B B

CC

C

C

D

D

E

FG

D

stewartmilnetimbersystems.com

Aberdeen

Peregrine House

Mosscroft Avenue,

Westhill Business Park,

Westhill,

Aberdeen AB32 6JQ

Telephone: 01224 747000

Fax: 01224 747499

GlAsGow

Kestrel House

3 Kilmartin Place,

Tannochside Business Park,

Uddingston G71 5PH

Telephone: 01698 804804

Fax: 01698 804806

MAnchester

Harrier House

2 Lumsdale Road

Cobra business Park

Trafford Park

Manchester M32 0UT

Telephone: 0161 866 6900

Fax: 0161 866 6976

oxford

Falcon House

Curbridge Business Park,

Downs Road, Witney,

Oxon OX29 7WJ

Telephone: 01865 303900

Fax: 01865 303999

smts@stewartmilne.com

stewArt Milne tiMber systeMs