Can You Add a Basement to a House?

by Charlie
Can You Add a Basement to a House

Basements are a fantastic way to ensure you have extra space in your home without eating into your backyard. Basements have quite a few advantages, such as staying cool in the summer, and offering an extra room, or storage space. They can also be a good place to go during a storm or another emergency.

However, if your house doesn’t have a basement, you may not be sure whether one can be added later. After all, they have to be dug under the foundations of the house, and you might be wondering if that is likely to cause stability or drainage issues for the rest of your property.

Can you add a basement to a house? It is possible to build a basement after the house has been built, but this isn’t done very often for a few different reasons. One is that it tends to be expensive, because the house’s foundations have to be changed to ensure that its stability isn’t compromised. You will gain a significant amount of space, but it’s a huge project that can get pricey fast.

Is Adding a Basement to a House Viable?

The answer to this depends heavily on your property, your funds, and your area. Basements aren’t recommended in areas that flood, and it may prove too complicated or too expensive to add a basement in some cases. You cannot add a basement yourself; you will need to hire professionals to do this job.

Because the basement will be dug beneath your home, you could compromise the entire structure of your house if you try to do it yourself. Even without this consideration, basements need proper reinforcing and drainage in order to be structurally sound, and licensed contractors should be the ones to undertake the project.

Not turning to the professionals could be extremely dangerous, and it is not recommended that you even attempt to dig a basement yourself. You should therefore contact licensed professionals, who will inspect your property, provide quotes for the work, and also assess how viable the project is.

In some cases, they may tell you that adding a basement isn’t possible. It is quite a complex project, and there are a lot of things to consider, such as how the existing home can be moved to allow the basement to be dug.

How is the House Moved?

The house needs to be moved off its foundations in order to dig a basement underneath. The company you engage will usually reinforce the house and then use a crane to move it to another part of the site. If this isn’t possible because of space constraints, they will raise the house up several feet off the ground and brace it there.

That might sound like a big project, and it’s one of the reasons that basements are rarely fitted retrospectively. The whole building has to be braced and lifted so that the foundations can be altered, the basement can be dug, and the area can be made structurally sound again.

Your contractor won’t start digging the basement with the house in place, because as soon as they start to hollow out the space underground, they will compromise the integrity of your home. They need to reinforce the foundations so that the house remains structurally sound.

Is Adding a Basement Later More Expensive?

It’s a lot more expensive to add a basement to an existing property, because of the requirement to move the property. If you’re building your own home, think hard about adding a basement before you proceed, because you’ll probably pay about 50 percent more to add one later.

In general, if a basement is being included in a property, it’s one of the first parts to be built. This means that the contractors building the house can construct the foundations to support the house with the cavity underneath, and it also means they can work without having to move the house first. This reduces the costs considerably.

Once the basement is complete, the rest of the house can be added on top, and this tends to be the most efficient and satisfactory approach.

There are often other associated costs if you add a basement later in the process. You may need to do things like partial replumbing and rewiring, which can quickly add up, as these will require you to hire contractors as well.

Does Your Location Make a Difference?

Your location will make a difference to how easily you can add a basement, or whether it can even be done. In some areas, basements present challenges because the ground is too soft and loamy, and in others, they can be problematic because of flooding risks. A contracting firm should be able to advise you on whether you can add a basement to your home.

Your location may also affect the cost of adding a basement. If the company has to do more to make the basement secure, prevent flooding, or stabilize your home, there’s a high chance that you will have to pay more to build it.

How Long Does It Take?

Adding a basement is a big decision and will usually take months of work. You should get time estimates from the company that will be doing the job, but it’s a good idea to plan for extra delays because it’s not uncommon to hit setbacks with building work. Expect at least 9 months for most jobs.

If you’re going to be using the basement as an extension of your living space, bear in mind that things like plastering, finishing the walls, adding windows, painting and decorating, etc., will take additional time and come with an additional cost. Remember to factor these into your time and cost estimates.

Final Thoughts

Adding a basement to an existing house is possible, but it’s a lengthy, expensive, and tricky process. It is much better to add the basement before the house is built if this is an option. If not, make sure you have money in reserve in case the project becomes more expensive than expected.

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