How to Form a Concrete Foundation

If you're building a new extension to your house, then you might need to know how to form a concrete foundation floor. Concrete foundations can be poured into any part of your house, however, it's important to make sure that this is done properly so that the floor will last you for many years to come.

The stability of the concrete foundations will affect the structure and integrity of the whole building. If there are any weaknesses in the foundations, then this will affect the building. Laying and forming concrete foundations is actually very easy with the right tools and accessories.

Step 1 - Work Out the Size

Calculate how deep you will need to dig the whole for the concrete slab. The thickness of the slab will normally depend on the size and the application of the extension. If it is a garage then it will typically require a thicker foundation.

Use a measuring tape to measure the size of the proposed concrete slab to make sure that it's the right size for the room in question.

Step 2 - Excavation

Now you need to dig and excavate the area of the foundation slab. Dig down twice the thickness of the slab. If you are going to make a slab which is 3 inches thick, then you will need to dig a hole which is at least 6 inches deep.

Step 3 - Cleaning the Hole

Once you've dug your whole you will need to clean it up. If there are any stones in the hole then take them out. Now you will need to compress the soil by using a compactor. Compactors can be rented from many building companies.

Now you need to put sand or gravel inside the hole. This will help drainage which will prevent any water from disturbing the slab.

Step 4 - Laying a Barrier

A barrier material needs to be laid to protect the concrete flooring. This is especially important if you are laying the concrete foundation for inside your house. Barriers are important to prevent moisture from seeping up into the concrete flooring.

Step 5 - Making a Frame

Construct a frame made out of wood which will contain the concrete. Use more sections of wood as screed rails to ensure the floor is level. When doing this try to ensure that the wood is straight and not bowed. The frame needs to be complete so that the concrete can't spill out.

Step 6 - Pouring the Concrete

The concrete can be mixed in a cement mixer, then poured into your wooden frame. The screed rails make it possible to level the concrete. TUse hand trowels to finish off the job.

Now you need to wait for the concrete to set properly. Make sure that you wait at least 2 months before laying a new hardwood floor. Use a sander to get rid of any high or low spots in the concrete flooring.