A foundation is the one part of a building that is almost impossible to fix cheaply once the walls are up. Cracked corners, doors that jam and floors that slope all trace back to decisions made before the first bag of cement was opened: how the soil was assessed, how the concrete was specified, and how well it was placed and cured.
TMSMT Construction builds foundations and structural concrete for houses, flats, shops, factories and warehouses across Midrand and greater Gauteng. Our work follows SANS 10400 and the design of a registered engineer, and it is built by people who understand how Highveld ground and weather behave.
Why Gauteng ground needs attention
Large parts of Gauteng sit on expansive clays and other problem soils. These clays swell when they take up water and shrink as they dry, and a footing that does not allow for this will move with the seasons. Dolomite, fill and uncompacted made-up ground bring their own risks.
For that reason we do not guess. A geotechnical investigation or at least trial holes on site tell the engineer what the ground can carry and how it is likely to move, and the foundation type is chosen from that information. Where a site has been filled or levelled in the past, we say so early rather than discover it halfway through excavation.
Foundation types we build
The right foundation depends on the soil, the load and the structure above it. We build and coordinate the following, always to an engineer's drawings where the building regulations require them:
- Strip footings under load-bearing walls for houses and small buildings
- Pad footings and stub columns for steel and portal-frame structures
- Raft and stiffened-raft foundations for reactive soils
- Piled foundations and ground beams where the soil near the surface is unsuitable
- Reinforced floor slabs for homes, shops, factories and warehouses
- Retaining walls, basement walls, water tanks bases and plinths
Reinforcement, formwork and placing
Steel reinforcement is cut, bent and fixed to the schedule on the drawings, with cover blocks that keep the bars where the engineer intended them to be. Formwork is set out, checked for level and braced so that it does not move under the weight of wet concrete.
Concrete is ordered to the specified strength and slump, and placed and compacted so that it fills around the steel without voids. On the Highveld, hot afternoons and sudden storms both threaten fresh concrete, so pours are planned around the weather and protected afterwards.
Curing, testing and sign-off
Strength is not only about the mix. Concrete that dries out too fast loses surface strength and cracks, so we cure slabs and footings by keeping them damp or covered for the period the specification asks for.
Where the engineer requires it, we take test cubes and arrange inspections before concrete covers the steel. Council inspectors and the engineer inspect footings and reinforcement at the stages set in the approved plans, and we build the programme around those inspections, not the other way round.
Slabs, floors and damp-proofing
A floor slab is more than a flat pour. It needs a compacted, well-drained platform, a damp-proof membrane under the slab, correct falls where water is expected, and joints placed so that cracking happens where you want it. For industrial floors we coordinate finish, joints and loading with the building's use.
Where a basement or retaining wall is involved, we plan drainage and waterproofing together with the structure. See our waterproofing page for how we protect concrete below ground.
Working with the rest of the project
Foundations rarely stand alone. They follow earthworks and site preparation and lead straight into brickwork or steel erection. We manage those handovers so that levels, sleeves for services and starter bars are right the first time.
If you are planning a new home, the foundations are also part of the NHBRC enrolment and inspection process. We explain what that involves on our residential construction page, and our building plan approvals service covers the drawings and council submission that come first.
Common questions
Do I need an engineer for my foundations?
In most cases, yes. SANS 10400 requires engineer-designed foundations where the soil is problematic or the structure is beyond the simple rules of the regulations. We work with registered engineers and build to their drawings.
What is a geotechnical report and do I need one?
It is an assessment of the soil on your site, based on test pits or boreholes. Engineers use it to choose the foundation type. On clay, fill or dolomite it is strongly advisable and often compulsory.
How long must concrete cure before building on it?
It depends on the element and the specification. Footings are usually built on after a short period, while slabs carry heavier loads later. We follow the engineer's instructions rather than a fixed rule.
Can you repair a cracked or settling foundation?
Often, but the cause must be found first. Movement from clay, leaking pipes or poor drainage needs to be addressed, otherwise the repair will crack again. We can arrange an engineer's assessment before quoting.
Do you build foundations for extensions to an existing house?
Yes. New footings must be designed to work with the old ones so the two parts settle together. See home extensions for how we approach that.
Architectural Construction Plans
Building Plan Approvals
Earthworks and Site Preparation
