Foundation Pier Types, Lifting, and Voids

Not all foundation pier types are the same.

The best pier types are the ones that hold the best. And those aren’t usually going to be the cheapest option. But as with most things in life, you get what you pay for.

Weather Affected Zone

Let’s quickly cover what the weather affected zone is in a foundation.

As I mentioned in a previous post, our expansive clay soil in the Dallas/Fort Worth metroplex contracts when it’s dry and expands when it’s wet.

So the piers, any of them, need to go below the weather affected zone. Some people also call this the active zone which is about seven to 15 feet below ground in the Dallas area. Otherwise, the soil movement will make the piers shift like crazy.

Any pier, regardless of pier type, that does not go below the weather affected zone will not support or stop the house from moving.

Press Pilings

This is what’s called a press piling.

With a press piling, they put one cylinder on top of another. Basically they just stack the pilings on top of each other. Some companies insert a cable down the middle of them, something like rebar, etc.

Now they make these looks really good on paper. But just because it looks good on paper, doesn’t mean it is. There are many situations where the pier ends up going in sideways underneath the house.

And with these types of pilings, they use the weight of your house to lower the piers. Where the problem comes in is if they can’t lower the pier far enough because the weight of your house isn’t heavy enough. This makes it highly possible the piers won’t go below the weather affected zone.

Press pilings are, in my opinion, worthless in almost all cases. It is the cheapest option and it’s what most contractors use. If you’re looking at JUST pier price, if the only thing that matters is price point, press pilings are what you’re probably going to get.

But I can tell you, I would never personally install or recommend installing press pilings to anyone.

I know a press piling company in town and that’s 50% of what they do. And the other 50% is going back to fix things. In fact, they keep a warranty crew on staff at all times. The warranty crew only does warranty work.

Steel Piers

With a steel pier, the contractor drives it into the ground.

It’s usually a thinner pipe so they can go down lower with these. But again, they are using the weight of your house to lower the piers.

So there’s still no guarantee they’ll go down below the weather affected zone. Although it’s much more likely they will because of the smallness of the actual pier.

Now it’s possible as well that these could also go in sideways, but that doesn’t happen very often.

Helical Piers

Helical piers, the most expensive option, are steel piers with one or more helical plates that anchors the pier into the ground.

It’s essentially rotated into the ground like a screw. It was designed to secure the pier in the ground. Foundation companies started using it for foundation repair at some point in the recent past.

The thought is that it will support the slab better. And they aren’t using the weight of the house to drive it into the ground so theoretically it should go down below the weather affected zone.

Drilled Concrete Piers

With a drilled concrete pier, they drill a hole into the ground and then pour concrete in.

With this type of pier, it’s a longer process. It’s usually takes a week to two weeks.

The company brings out a machine that drills down into the ground. Then they put rebar down into the hole and fill it with concrete. And then the concrete has to sit for seven days. So your yard is torn up for 7 days or more.

This is an older way of doing foundation work.

But I’m a big fan of drilled concrete piers. You know exactly where the actual pier went. You can literally look down and see how deep it went, etc. Although this is what I’d recommend, there are some downsides to it as well re: the longer process, the messiness, etc.

But it is also cheaper (and better, in my opinion) than the steel or helical piers.

Mud/Foam Jacking

Plumbing Test

Also if you pump mud or foam under the house, make sure the company tests the plumbing system beforehand because you don’t want that mud or foam getting into the plumbing system. Nobody should ever pump foam or mud under the house without having a plumbing test first.

And it’s my recommendation that they run water through the system when they’re pumping the foam even after they’ve checked to make sure there are no leaks.

When they are pumping the mud or foam, not only should they be running water through the whole system but that they also have a dedicated person watching the sewer system to make sure that nothing gets in there while they’re doing it.

This is especially important if they’re lifting the foundation. Anytime you lift and level a house, the possibility exists of pulling the plumbing pipes apart. Whether that be from putting in piers or from the mud/foam jacking.

You want to make sure nothing happens during the lifting process. That the lifting didn’t create a leak even if there wasn’t one beforehand.

A Few More Things to Keep in Mind

Whether you just got repair work done or you want to keep your current foundation safe, here are a few things to help you out with that.

Rain Water Drainage

You need to keep water away from the foundation.

Gutters will help with keeping water away from the foundation. If you’ve got a pooling spot around the foundation, even a small pooling spot, that’s not good for the foundation at all.

You’ve got to keep excess water away from the foundation at all times. The expanding and contracting clay soil we have in D/FW can cause serious damage to your foundation.

Roots

Roots can also cause problems to foundations.

Consider getting a root barrier drilled into the ground. This is a barrier that is buried to keep those roots away from the foundation. It’s buried between the trees and the foundation.

Or if it’s an option you are OK with, cut down the trees. You’ve got to do something to keep roots out from under the house.

Roots grow to water. And they absorb a lot of moisture, a lot of water out from underneath the foundation.

Foundation Watering System

Something that helps to protect your foundation is a foundation watering system.

This is a fantastic video. It will tell you how to build your own foundation watering system.

Foundation watering systems keep your foundation consistently moist at the right amount of moisture. This prevents the soil from expanding and contracting against your foundation. It’ll cost you a couple hundred bucks, and I highly recommend having one.

Wrapping It Up

As far as the pier types, a lot of people believe there are good things about all of them.

I’m personally a huge fan of drilled concrete and steel piers. And again, I will never use press pilings — ever — in a house I own. And helical I feel is overkill in most cases.

But I always recommend you find a good foundation repair contractor that you trust and go with what that person says. That is my general rule of thumb.

And remember, if you go cheap then you should count on paying more now and later when they put in extra piers. So be sure to keep that in mind.