Most commonly used foundation for domestic construction in the last 60 years.

The majority of soils in the UK have sufficient bearing capacity to have a simple strip of concrete.

• Soil type • i.e. minimum depth in cohesive = 750mm (not usually less than 1m in clay) • minimum depth in non‐cohesive = 450mm

2 storey building could have a foundation wider then 500mm special if soils isnt good

2 storey building could have a foundation 500mm wide

• Other factors – • Presence of trees • Risk of frost • Proximity to adjacent services

SIZE

Bearing Capacity of the soi

Building load

timing

Cost

Working space for labourer

The WEAKER the soil and HEAVIER the building the WIDER the strip

No need for planking and strutting (cost savings) • Potential time and labour savings

• No additional working space required.

HEAVEY

Additional cost (more concrete) • Economical? • Service entry ducts • Good access for lorry

Cheap

The most common form of foundation

• number of obstructions (e.g. old basements) in ground

Easy to do

where access for piling is difficult

for larger foundations

foundations can be used for sloping sites, where access is restricted (i.e. for piling), there are obstructions in the ground.

Designed by an engineer

for sloping sites

Spreads loads from ‘superstructure’ to piles

– Always includes reinforcement

Cast in situ or precast.

cheap and easy to load

No standard solution – individually engineered (expensive) (unlike strip)

t foundations have to be individually engineered, and cover the entire footprint of the building to ‘float’ the load across the soil.

Need a lot of time

mining subsidence is possible

soils is of very poor bearing capacity

significant differential settlement likely

stiffened and reinforced concrete which extend under the entire footprint of the building

Cheap

strip or pier foundations cover 50% of footprint

former mining; or • where the soil has significantly poor load bearing capacity • e.g. peat, filled ground, soft clay, soft silty clay and soft sandy clay