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School of the Built Environment
BUILDING REFURBISHMENT & MAINTENANCE
FURTHER ASPECTS OF
MODERNISATION
School of the Built Environment
OVERVIEW
• Why commercial modernisation
• Typical external improvements
• Typical internal improvements
• Over-roofing
• Over-cladding
• Re-cladding
School of the Built Environment
LEARNING OUTCOMES
1. Understand the benefits and limitations of
prescribing improvements for commercial and
industrial refurbishment schemes.
2. Identify the measures for improving the technical
performance of a commercial building’s main
elements.
3. Appreciate the design requirements of major
improvements such as over-roofing and over`-
cladding.
School of the Built Environment
Reasons for CommercialRefurbishment
• To improve the building’s aesthetics
• To improve the lettable floor area
• To satisfy changes in regulations/legislation
• To cater for a change in use
• To upgrade services
School of the Built Environment
COMMERCIAL REFURB. RATIONALE
• Building deficiency: requires attention due to poor condition or amenity
• Changing work patterns: changes in the way in which the bldg is used.
• Market requirements: Bldg no longer economical due to inefficient heating
system or unlettable
• Enhancing company profile: major org can have regular changes or
images to reflect corporate color & images
• Improving indoor air quality
School of the Built Environment
TYPICAL EXTERNAL IMPROVEMENTS
• Envelope upgrade– Re-roofing: full or partial removal & replace with new. Normally involve thermal upgrade.
– Over-roofing: Install complete new roof over the existing roof.
– Over cladding: New cladding to the ext face of the outer wall. Improve aesthetics,
thermal performance or weather resistance.
– Re-cladding: Removal or overlaying the extg external cladding with new.
• Flood lighting: Intro high powered ext lighting for safety or security.
• New Canopies: provide extg weather protection over access points.
• Revolving Doors: To replace conventional door to reduce heat losses & draughts &
improve security.
• Bollards & Crash Barriers: Install at ext ext perimeter to improve safety, alter
pedestrian flow around building to reduce risk
• Ramps & Pavings: improve amenity around bldg or by regulations.
• Landscaping: improve security & privacy, improve ground drainage & risk of flooding
School of the Built Environment
TYPICAL INTERNAL IMPROVEMENTS
• Refit toilets: renewing units & appliances
• Refit staff facilities: improve staff
welfare ie. Floor coverings, furniture, etc
• Refit services: Electrical wiring, elect
appliances; cold & hot water supply, etc
– HVAC: provide better thermal comfort and
acceptable indoor air quality
– Lighting: energy savings
• Renew– Entrances: doors, shutters , glazing
– Floor Finishes: Vinyl, carpeting,
laminates
– Wall Finishes: paper, carpeting, paint
– Ceilings: suspended tiling, plaster boards
School of the Built Environment
PYP
School of the Built Environment
OVER-ROOFING
• Reasons – failure of existing flat roof
• Options– Recover/Replace Existing Flat/Pitched Roof: this option only
involve upgrading to the weather protection, ie the extg tiles, slates or felt are replaced with new.
– New Pitched Roof: with entirely new members
School of the Built Environment
OVER-ROOFING
• New roof structure methods– Portal/Moment-Resisting Frames
– Trusses (With or Without Purlins/Attic/Long-span)
– Propped Struts (eg, “AshJack” or “SpeedDeck”)
– Purlins and Rafters
• Requirements – structural integrity / access /
building services / access to roof
• Indicative costs (£50/m2 to £200/m2)
School of the Built Environment
OVER-ROOFING STRUCTURE
School of the Built Environment
OVER-ROOFING CONSIDERATIONS
• Structure & condition of existing roof & wall
• Extent & location of services
• Need for fire compartmentation
• Access around building (crane, scaffolding
and storage)
• Disruption to tenants
• Programming of works where wall
over cladding is also undertaken
School of the Built Environment
School of the Built Environment
SERVICES
School of the Built Environment
FIRE COMPARTMENTATION
School of the Built Environment
ACCESS + STORAGE
School of the Built Environment
School of the Built Environment
School of the Built Environment
Another Type of OVER-ROOFING
School of the Built Environment
Claddings
School of the Built Environment
Over-cladding - Improve aesthetics, thermal performance or weather resistance
School of the Built Environment
OVERCLADDING
• REQUIREMENTS– Protection: against wind, wind-driven rain, impact & lightning
– Appearance: acceptable appearance keeping
with convention & surrounding env.
– Durability: Life span at least equal to the overclad structure.
– Insulation: incorporate thermal insulation
(to reduce heat loss & sound transmission)
• FAÇADE DESIGN– Style
– Colour
– Texture
• MATERIALS– Frame: stainless steel, Al, Composite plastics, timber
– Glazing: strengthened, coloured, etc
School of the Built Environment
TYPES OF OVERCLADDING
• RAINCOAT SYSTEMS
– Types:
– - Insulated Render: thermal insulation
fixed to the substrate over which is applied a normal or chemical render.
– - Insulated Brick Slip: thermal insulation fixed to the
substrate over which is fixed with a thin brick and thereafter grouted.
– Suitability: low rise dwellings where finishes are
rendered and brick are used
– Precautions: Expanded insulation can increase risk
of fire spread> must be properly bonded to prevent detachment.
School of the Built Environment
TYPES OF OVERCLADDING
• RAINSCREENS SYSTEMS
– Types:
– - Drained and Back-Vented
Fiber cement panels(or metal composite) are
considered a drained/back ventilated rainscreen.
This is a panelled wall system installed to framing
using clips that hold the panels away from the
structure. The clips provide different depths of air
space depending on the designer’s preference and
moisture is released through this air layer. Fiber
cement panels are installed over a water track with
weep holes. If it is a metal composite, when
condensation or penetrating rain water can drain
down the back of the sheeting where it is directed
outside at the regular flashing location.
School of the Built Environment
RAINSCREEN CLADDING PRINCIPLES
School of the Built Environment
EXAMPLES OF RAINSCREEN
School of the Built Environment
TYPES OF OVERCLADDING
• Pressure Equalised SystemThis rainscreen cladding system is cavity compartmentalised to control pressure and stop the spread of fire through the building.
This system allows wind to blow in and behind the rainscreen panels, equalising the pressure, resulting in a very low wind load on the panels themselves. Design in accordance to BS6399-2-199.� Cavities are compartmentalized� Openings calculated to allow rapid ingress and egress of air� Water ingress reduced by ‘equalization’ of internal and external pressures
(pressure moderated system)� Drained above compartment levels� Suited to tall areas of rainscreen� Design intensive� High pressures generated at corners require that the centres of vertical
compartments are reduced.
School of the Built Environment
TYPES OF OVERCLADDING
• Pressure Equalised System
– Suitability: medium or high rise dwellings where finishes are
rendered and brick are used
– Precautions: enclosed ventilated cavity can act as
– a chimney directing flame and fire up the bldg facade
School of the Built Environment
Fire Stops in Cladding
Over cladding – fire break detail
School of the Built Environment
School of the Built Environment
RE-CLADDING
• REASONS
– Premature Degradation: fails prematurely or reached the end of its service
life.
– Damage: result of storm, impact or vandal.
• PROBLEMS
– Approvals: From P&BC where major refb required.
– Fixings: Fixing to a new structural points on bldg.
Assessment of structural loading
– Finish: required to match existing or surrounding.
• OPTIONS
– Curtain Walling
– Special Cladding
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