frequently asked questions about concrete foundations

Let’s get right into it: what exactly is a concrete foundation, and what is it used for?

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It’s just what it sounds like, really; if you’re building a house, garage, shed, pool, etc., you’ll need a level surface to hold whatever structure you’re building above the ground. This isn’t all it does, though. A foundation keeps moisture out, resists any movement of the organic material around it (i.e. dirt, sand, etc.), and keeps out the cold. Simple, right?

It might not seem that way if you’re unfamiliar with laying a concrete foundation.

That’s why we wrote up this list of frequently asked questions about foundations, from repairs to what certain terms mean. As your contractor, keeping you well-informed is important to us, and we welcome any other questions you might have. By all means, read on, and if we didn’t cover something here don’t be afraid to bring it up!

What do you mean by “different kinds of concrete foundations?

Laying a concrete foundation is a lot more than just pouring the mix into a hole you dug. There are three different types of foundations, and they all provide different benefits for the structures they support. Let’s take a look at each kind separately.

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• T-Shaped

A T-shaped foundation is designed to support your structure in areas where the ground is prone to freezing. First, a footing is poured below the soil’s frost line. What is a footing, you ask? Basically, a footing is concrete reinforced with rebar that contractors pour into a trench they’ve excavated in the soil. Why would you need a footing? They help support the foundation itself, and prevent the soil around it from settling too much. They’re very good to have if your soil is problematic for foundations.

So, back to t-shaped foundations. Once the footing is placed below the frost line, the foundation is placed on top in a t-shape and then cured. The walls of the structure are then added on top of that, and then the slab (layer of concrete of a few inches thick) is poured between the walls. It’s important that the footing be wider than your structure’s walls, so that the base of your foundation has extra support. Concrete is poured a total of three times in this type of operation.

• Slab-on-grade

A slab-on-grade foundation, unlike the t-shaped variety, is more often used in areas where freezing doesn’t occur. The slab, in this case, is monolithic, which means it’s all poured in at one time. It’s usually poured on top of a bed of crushed gravel, laid beforehand, that will improve overall drainage. The outside edges of the slab are designed to be thicker than the center, forming an integral footing. Wire mesh is also often laid within the slab so that the concrete doesn’t crack as easily. If there is a chance of frost, insulation should be added to this type of foundation to prevent damage from frost heaves.

• Frost-Protected

You can only have this type of foundation if your structure is a heated one. With this method, two sheets of polystyrene insulation are added to the foundation. But where are they added? Usually, one is placed on the outside of the foundation wall, and the other one is laid horizontally on gravel at the base of the wall. This helps hold heat from your structure in the ground, and keeps the edges of the slab from losing heat. The ground around the footings, therefore, stays above freezing temperatures, which prevents cracking. 

How is repairing a concrete foundation usually done?

First, you need to know the signs that indicate something might be wrong with your home’s (or other structure’s) foundation. If your walls are cracking, you have odd bulges in your floors, or you’re having trouble closing your doors, there might be a foundation-related problem. Cracking and bulging in general are usually signs of foundation trouble. Is your driveway, home, commercial building, or pool deck experiencing these things? Ask us to come out and assess the situation, and we’ll be happy to look into it for you.

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What do we do to repair things, though, without disrupting your entire home and family?

Most commonly, we’ll try methods called slabjacking and piering. These are usually sufficient to fix a settling foundation.
Slabjacking is when we pump grout underneath the foundation slab until it’s lifted up to its normal elevation point. The grout solidifies and bears the entire weight of the slab, supporting it. This is usually done for smaller slabs, such as those underneath swimming pool decks, driveways, or sidewalks. It’s a simpler method than piering, and it won’t work for very large foundations like piering does.
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Piering is a little different. This is done by driving steel posts through the soil, and then using hydraulic jacks to raise up the slab. If a large house or commercial building is having problems with the foundation shifting, piering is the repair method you’ll want used. There are many benefits of repairing a foundation this way. These include minimal disruption of the dwelling, low cost (replacing the entire foundation can cost ten times more), no heavy equipment used, no destruction of the home’s yard, and portable equipment. 

What about insurance? If I have an issue with my foundation, can they cover the cost?

Our advice on this is to check your policy. Most of the time, policies cover very specific disasters. Your insurance company might be able to partially cover foundation repairs if your foundation sustained damage due to one of these risks: an explosion, a fire, or a tornado. Of course, you’ll have to check your insurance policy before assuming the cost will be covered. Unfortunately, most of the time insurance companies don’t cover the usual causes of foundation, like poor construction or soil expansion.
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At the risk of making this article too long, we’re going to end things here. hope that we’ve covered your foundation- and repair-related questions in a way that was simple to understand. Don’t be shy; contact us if you have any other concerns, and we’ll do our best to address them.