Topic A2
Common structural
forms for low-rise
construction
Cross-wall construction
Structural panels
Traditional cavity wall
Timber-framed construction
Traditional cavity wall
• A wall made with two leaves with a space
between.
• The cavity stops rain getting into the inside
of the building.
• Insulation is installed in the cavity for
thermal and sound insulation.
• Strong and durable
• The wall below ground transmits loads
safely to the foundations.
• Slow to build
• Need skilled bricklayers
• Wet construction needs time to dry
between lifts
• Can’t carry out bricklaying work in heavy
rain or frost
• Can be difficult to get supplies of brick in
times of high demand
Blockwork
Cross wall construction
Crosswall benefits
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Crosswall buildings are durable
Good sound insulation through floor and wall panels
Low maintenance.
Quick to build. The precast components are brought
to site ready to be placed within the structure.
First and second fix work can start before the build is
completed.
Can have a skim finish. This has the benefit of fast
and cost-effective construction.
Concrete is good at storing heat and has a high
thermal mass.
Concrete has good fire resistance.
Timber-framed construction
• This is a pre-fabricated method of
construction with components made offsite and then transported onto site for
erection on site
• Timber framing use – domestic dwellings
up to 3 storeys in height.
• Position of insulation – usually between
the studs, built in to the panel in the
factory before assembly on site
Timber frame
Timber frame
Timber frame pros and cons
• can use off-the-shelf designs
• internal trades can start work before building is completed
• reduced drying time as no wet internal finishes are used
• a large number of houses can be erected in a single day.
• quicker overall completion time
• reduced site labour saves money.
• non-skilled labour can be used
• more energy efficient than brick when built to corrrect standards
• Different external finishes can be applied allowing variety of design
• timber can decay if exposed to excessive moisture
• less public confidence in this structural form
SIPS
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Structural insulated panels are a
composite made of an insulating layer
sandwiched between two layers of
structural board.
The board is usually orientated strand
board (OSB) or stirling board.
This can be recycled easier than brick
walls
The core is made from expanded
polystyrene foam (EPS),
SIPs are very strong.
Lighter than brick buildings so foundations
need less concrete.
SIPS can be used for exterior wall, roof,
floor and foundation systems.
Faster to build than brick buildings
First fix work can start sooner than in
cavity wall structures
SIPS benefits and drawbacks
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good thermal properties, with fewer
drafts because SIPS are already
insulated.
Fast construction so less on-site
resources used. This saves time and
energy usage.
Less on-site waste as panels are
constructed off-site.
Fewer trades needed.
Panels can be used as floor, wall, and
roof.
Lighter weight than cavity walls so
foundations need less concrete.
Poor noise control – can have poor
speech privacy between spaces.
Outer leaf materials can be recycled
easier than traditional masonry
materials.