Pouring a concrete foundation: preparation and construction

A concrete foundation starts with the ground on which you build. The bearing capacity of that ground, the structure above it, and the correct execution together determine how the foundation performs its function. Below you can see how we deliver, distribute, and finish concrete, with images from a site where Glansbeton collaborated with concrete plant Wijckmans.

Which concrete foundation suits the construction?

A foundation transfers the load of a building or structure to the subsoil. A concrete slab, foundation strips, and foundation beams are not interchangeable solutions. Moreover, a floor slab on the ground is not automatically a general foundation slab that also supports the load-bearing walls and columns. That distinction should be clearly indicated on the plan.

For a garden house, a brick outbuilding, a swimming pool or a house, different requirements may apply. The weight of the structure is only one factor: the distribution of loads, the soil and the connection to existing buildings also matter. The necessary dimensions and reinforcement follow from the design. A standard thickness from an online example is therefore not a reliable order for your site.

Preparing substrate, formwork and reinforcement

Before the concrete is ordered, the measurements and heights must be fixed. Where will the edges be? How does the slab connect to doors, the exterior landscaping and any existing floors? Which pipes or penetrations must be installed before pouring? Such agreements prevent adjustments being needed afterwards in a new slab.

The subsoil must be prepared according to the design. A concrete slab does not automatically make an unsuitable subsoil suitable. If in doubt, have the soil and foundation choice assessed. Excavation near an existing building also requires attention: the support of the existing structure must be maintained.

Formwork, plastic sheeting and reinforcement each have their function

The formwork keeps the fresh concrete within the agreed contours and partly determines the edges and levels. It must be sufficiently supported for execution. Any foil, insulation and other layers are installed as specified in the floor build-up. They serve different functions and do not replace each other.

Reinforcement is placed according to the reinforcement plan, using suitable spacers to maintain the designed position and concrete cover. It should not lie loose on the ground. The type of reinforcement, overlaps, and cover depend on the project; do not arbitrarily adopt measurements from another site.

When is a frost edge necessary?

For foundations exposed to frost, the design must take into account the soil and frost action. A recessed edge can be part of the solution. However, the depth and shape are tailored to the construction and conditions, not solely based on a general rule of thumb. Also discuss how the foundation will be protected if construction is temporarily halted.

Pouring concrete: directly from the ready-mix truck or using a pump?

The photos show the delivery of concrete through a pipe from the ready-mix truck. For this site, Glansbeton collaborated with concrete plant Wijckmans. The crew distributes the delivered concrete and finishes the surface. This cooperation requires a coordinated delivery: the supply must match what the crew can process at that moment.

Direct delivery is an option if the pouring location is accessible and the route and parking area are suitable for the loaded ready-mix truck. Consider more than just the width of the access. The load-bearing capacity, bends, height restrictions and distance to the pouring location also determine whether the delivery is feasible.

When the ready-mix truck cannot get close enough, a concrete pump can bridge the distance. For this, a suitable setup location, sufficient space and a pre-agreed pipe route are also necessary. A pump solves an accessibility problem but does not replace the preparation and inspection of the site. Therefore, discuss the delivery method before the pouring day.

Finishing the concrete slab and curing

The desired finish depends on what will happen later on or with the slab. Will there be a floor build-up on top, or will the concrete remain visible? Is a certain flatness required for the next contractor? These requirements must be known in advance. On this site, the images show how the fresh power-trowelled concrete is finished with a screed board.

After pouring and finishing, the concrete needs time and appropriate curing to harden. Hardening is not the same as simply drying out. Protection against too rapid moisture loss and weather influences is part of the work. The method used must correspond to the conditions and any subsequent finishes.

When walking on the slab again, laying bricks or driving with materials is allowed, you agree based on the execution and the required strength. One fixed number of days does not suit every slab or every season. More explanation can be found in our article about concrete curing and aftercare, including considerations for hot weather.

What determines the price of a concrete foundation?

A price per square metre only means something when the scope of the work is clear. Two slabs with the same surface area can have different thicknesses, edge finishes, reinforcement, and delivery methods. Accessibility and the distribution of preparatory work also influence the quotation.