How to Build a House Foundation and Why You Need One

What types of foundations are there?

There are three main foundation types used when building a foundation for a house and the one you use will depend on several factors including the climate and soil conditions and whether you want your house to have a basement.

Concrete slab foundation

A concrete slab foundation is what most people think of when they hear about building foundations. It consists of a concrete slab that is poured into a hole, dug to the desired depth for the foundation. Drainage pipes and water pipes will be laid in the concrete, which can cause problems if they ever need to be repaired.

Concrete slab foundations are suitable for warmer or more temperate climates where the ground is less prone to freezing and thawing.

This type of foundation has the benefit of keeping out termites and other burrowing insects and is also generally the cheapest way to build a house foundation. It also requires the smallest amount of maintenance, compared to other foundations. Home builders are contractors that provide residential construction services.

Crawl space foundation

With a crawl space foundation, there is a gap between the earth and your house (the crawl space). The foundations will have a concrete base and then foundation walls that stand on these footings.

Crawl space foundations work best in dry climates, as in wetter regions the space can retain moisture and get moldy. This means it's important to ventilate your crawl space. This type of foundation is also very suitable for sloping lots and has the advantage of easy access to pipes and wiring for repairs.

In general, they are more expensive than slabs and require more maintenance. But on the positive side, if you want to do major remodeling it's much easier to move the location of bathrooms and kitchen in a house with a crawl space, as you can access pipes and drains more readily.

Basement foundation

The third, and most expensive type is a basement foundation, where you have a very deep foundation, incorporating a basement room, or rooms, under the main structure of your house. You might have a full basement or partial basement.

One negative of basement foundations is that they are more prone to problems with damp and mildew, so that is something to be aware of.

Full basement

A full basement will be the same size as the footprint of the house and have foundation walls, either made from cinder blocks or poured concrete. The foundation should be deeper than the frost line (how deep frost reaches into the earth).

If you are building basement foundations it makes sense to build them deep enough to create a living space, so generally, they are at least 7 feet deep.

Partial or daylight basement

If you are building a house on a slope you can create a daylight basement, where one side is dug deep into the earth and the other side (lower down the slope) is exposed to daylight, so you can put in windows and doors.

With this style of basement, you will have more livable rooms, and managing moisture and mildew is easier.

General contractor basically covers all spheres of the residential or commercial construction business.

How to build a house foundation

We'll outline the main steps to building a solid slab foundation for your house.

Clearing

First, you need to clear the land of any debris and check the ground to make sure your foundation is at the correct depth.

Marking

Marking out the foundation is a vital and somewhat complex stage in preparing the site. You need to make sure everything is level and you're working from a clear point so everything is dug to the correct depth. You'll mark out where needs to be dug and to what depth.

Digging

Once the site is prepared and marked out, excavation can begin. At this stage, your builder will be removing a lot of soil so the building site will be busy with trucks clearing it away. If you are building a basement foundation this will be a more involved process.

Once you have your trenches they might have gravel or polythene added for drainage and waterproofing. A wooden frame for the foundation to be poured into may also be created.

Pouring

Then you will pour the concrete into the footing trenches, making sure that any pipes or drains are placed correctly in the concrete. At this stage making sure the concrete is level is vital.

Curing

One of the most important steps, after your foundation has been installed, is allowing it to cure properly. To ensure your foundations are strong it's important that the concrete cures over several days, and doesn't dry too rapidly, so you may need to mist it with water. Equally, you need to make sure to protect it from the rain, which can cause imperfections on the surface.

Once this stage is complete, the construction of your house can begin in earnest.

Frequently Asked Questions

How do you build a foundation for a house?

The key stages in how to build a house foundation are:

• Preparing - clearing the land and carefully marking out the footprint of the house.
• Digging - digging the soil away where the foundation will be.
• Pouring - pouring the concrete into the area you have dug.
• Curing - ensuring the concrete dries correctly to form a strong, solid footing for your home.

What is the cheapest way to build a foundation?

The cheapest type of foundation is a slab and this is usually the easiest to build as well. While it doesn't offer the added living space of a basement or the easy access to below floor services, like a crawl space, it has many advantages including strength and waterproofing.

What are the 3 types of foundations?

The three main types of foundation are:

• Concrete slab — the cheapest and most straightforward to construct, but not ideal for very cold climates.
• Crawl space — works well on sloped lots and dryer climates and gives access to pipes and wiring, but requires more maintenance than a slab.
• Basement — best suited for very cold climates, and can give extra storage or living space, but the most expensive option.

How deep do foundations need to be for a house?

The depth required for foundations will depend on several factors but in general, they should be at least 12 inches below the soil line and the frost line.