Extreme Structures is a civil engineering company specializing in the design & building of concrete raft foundations. As raft contractors, we can help with residential and commercial foundations in Pretoria, Centurion, and Johannesburg. Even though we are based in Gauteng we have help with projects across South Africa. Our professional team has the experience to deliver any job, big or small on time and in budget.

We do not take any short cuts and adhere to the engineer’s specifications & design. All our projects are monitored, inspected & certified by an engineer to ensure we deliver only the highest of standards our customers have grown accustomed to.

Our complete scope of works for a raft foundation includes:

What is a raft foundation?

A Raft foundation is a reinforced steel and concrete foundation used to build on soil with weak support or problematic ground conditions like turf, dolomite or clay. Utelizing an interconnected steel mech system and under ground beams the raft foundation is built to float ontop oft the soil it is built on. It can also be used on projects that have a time constraint as the turnaround time for construction is much shorter than conventional ground slabs.

Concrete raft foundation design

The concrete raft design is done by a structural engineer and it consists of a continuously reinforced slab with excavated ground beams that floats on top of the ground. When designing a raft the engineer looks at soil conditions and the load the raft has to carry.

Designs for a raft foundation should include the engineer’s layout plans and placement notes. An architect cannot design or certify a raft foundation; it has to be done by a qualified structural engineer. In conjunction with professional consulting engineers, Extreme Structures can provide complete raft foundation construction solutions. Contact us today for a competitive quote or to arrange a site visit.

Raft foundation construction

The first step in constructing a raft foundation is to excavate the soil to the desired depth and leveling the construction site. If required the soil is compacted and leveled again. After this a waterproof plastic sheet is laid over the excavated soil and reinforced steel mesh is installed and tied down. Formwork is then erected to create the shape and levels of the raft foundation followed by the install of all required services like an electric conduit, water pipes, and drainage. All steel placement and ground beams have to be inspected before any concrete can be poured.

Once the concrete has been pour it is important to maintain the slab. In the summer it must be kept wet so it does not dry out too quickly and crack and in winter it must be covered with plastic to prevent it from freezing and cracking. Within 28 days a raft foundation has cued enough for construction to commence.

Let Extreme Structures construct your next Raft Foundation. Our reputation is earned & excellence is in our products. Request a free slab quote today.