interior settlement methods pros cons

5 Options to Fix Foundation Settlement Under Your Slab w/Pros and Cons

You’ve got interior foundation settlement but what can you do about it? Is there only one way to tackle this problem? Or are there options to handle foundation issues happening under the middle of your home? What about the pros and cons of these options?

Anchor Foundation Repair Bryan College Station

At Anchor Foundation Repair, we have been inspecting and repairing Brazos Valley foundations since 1985. We have helped thousands of homeowners and installed thousands of piers to correct interior settlement problems. We can tell you how we do this and can also share other options you might consider.

This article presents 5 repair options to handle homes with interior settlement. Even though we only do one of the approaches (drilled piers), we can fairly present the pros and cons of each choice. We want to help you even if that means offering alternative methods and contractors when they might be the best for your situation.

The 5 Ways to Handle Interior Foundation Problems

Foundation Repair in the Brazos Valley

Most homes can have their foundation repaired using an exterior approach where all your problems can be fixed with extra support under the perimeter of your home. The majority of repairs take place outside the home and the repair team doesn’t need to enter the home very much. 

About 10 to 15% of the homes we inspect and repair each year also need work under the middle and we call this *interior* settlement – this is you right now. Interior foundation problems are inherently more difficult to handle because they are underneath the center of your house. Like how do you get under there??

Here are 5 ways to handle repairs with interior foundation settlement:

  1. Drilled bell-bottom piers
  2. Concrete pilings pressed from the interior
  3. Concrete pilings pressed via tunneling
  4. Polyurethane foam injection
  5. A combination approach

Don’t worry, we will explain these a little and then offer the pros and cons of each next.

The Pros and Cons of Interior Foundation Repair Options

pros and cons in foundation repair

Each method or technique will be described in general terms, but we do have other articles to reference for each approach to direct you to more detail. After each description, you will find a basic list of pros and cons for each. It’s very orderly and organized, but most importantly unbiased and fairly presented.

1. Drilled Bell-Bottom Piers

Drilled piers are one solid piece made on-site from steel-reinforced poured concrete. The piers reach a depth of 10 to 12 feet where the soil is less reactive to surface moisture issues. The bell-bottom shape of the pier both resists soil uplift and lateral movement to maximize stability. 

The home would have drilled piers installed on the perimeter of the home as well as under key locations beneath the middle of the home where the slab needs to be raised and supported. Drilled piers work by creating a strong and stable base from which to lift the home and secure it in place at its proper elevation.

Work is done by going through the floor and slab inside the house. The process of installing interior drilled piers does take time and requires significant work inside the home.

interior foundation repair

Pros of Drilled Piers for Interior Settlement

  • Drilled pier depth and straightness can be verified
  • One-piece poured concrete piers are less susceptible to soil movement
  • Bell-bottom base resists uplift and settling
  • Effectiveness of drilled piers does not depend on soil moisture conditions at installation
  • Lower call-back rate on interior drilled piers vs exterior piers

Cons of Drilled Piers for Interior Settlement

  • More expensive to install
  • Longer installation time
  • Construction inside the home requires move-out
  • Extra costs are higher due to flooring impact, and move-out

2. Concrete Pilings Pressed from the Interior

Concrete pilings are pressed into the ground one on top of the other. Each precast cylinder is 6” in diameter by 12” long. Each one is driven into the ground one at a time stacked on top of one another until you can’t push anymore down.

concrete pressed piling foundation repairs

The home would have concrete pilings both on the perimeter of the home and supporting the interior. Pilings work by creating tension between the ground and the home similar to a battery held in place by a spring. The tension is what holds the home in place. The degree of tension can change depending on the moisture levels in the soil at installation time vs. later on.

Accessing the support points under the interior of the home is done by going through the floor and slab to reach beneath the home. The construction zone inside the home would be similar to drilled piers requiring flooring removal and extensive work inside the house.

Pros of Concrete Pilings for Interior Settlement

  • Faster install time than drilled piers due to use of precast concrete
  • Less expensive than drilled piers due to faster install time

Cons of Concrete Pilings for Interior Settlement

  • Pilings have less depth than exterior piles
  • No way to verify that pilings are straight and aligned
  • Moisture level on installation day impacts future effectiveness
  • Construction inside the home requires move out
  • Higher extra costs from flooring impact and move out

3. Concrete Pilings Pressed via Tunneling

Creation and installation of pressed pilings via tunneling is similar to pressed pilings in the description above with one exception. Instead of accessing the support locations under the home by going through the interior floors and slab, all piling locations are accessed by tunneling underneath the home.

digging an under-slab tunnel

A system of tunnels would be dug out to reach each support location required beneath the home. Damage to flooring surfaces is avoided and there is no extensive construction work inside the home. 

The upside to tunneling is that the homeowner would not need to move out during the repair process. The downside is that extensive tunneling adds significant expense to the homeowner due to increased work time.

Digging a series of tunnels under your home also requires backfilling those tunnels. The pressed piling process does not always compensate for additional voids created under the home when the slab is raised. The empty space created by raising potentially remains under your home unfilled with additional material. 

They *might* fill in both the tunnels and the voids with backfill material, but that soil can be subject to additional settling as well.

Pros of Pressed Piles via Tunneling

  • No mess or construction inside the home
  • No need to pack up items or move out
  • No holes cut in flooring or slab to access support locations

Cons of Pressed Piles via Tunneling

  • Extensive tunneling results in the highest costs
  • Raising creates voids under the home, voids are not filled in with mud-pumping
  • Creates a situation where settling could occur again
  • Other cons (listed in option No. 2) of how pressed pilings are made and conditions at installation time

4. Polyurethane Foam Injection

Injecting a specialized polyurethane foam under your home is indeed a form of foundation repair. Some call it polyjacking, poly leveling, or polyfoam injection. Instead of adding support under particular points of the home that need to be lifted, the foam lifts the foundation and fills space as it expands and then dries into a rigid, supportive material.

polyjacking for foundation repair

The polyfoam is injected by drilling small holes into your floors and slab and the material is pumped beneath the center of the home. We’ve got a whole article that explains polyjacking in more detail because it is a very different concept from other methods of foundation repair.

Polyfoam does not penetrate into the ground, it just rests on the soil surface under your home. Because there is no penetration to more stable and less reactive soil, this method’s long-term effectiveness in expansive clay soils is something to question.

Pros of Using Poly Foam for Interior Settlement

  • Least expensive of all the repair options listed
  • Shortest install time compared to all other options
  • No mess inside the home, hard flooring damage is minimal

Cons of Using Poly Foam for Interior Settlement

  • Non-penetrating surface-level treatment
  • Can’t do significant lifting, only supplemental
  • Higher risk of additional settlement
  • Shorter warranty times offered

5. A Combination Approach

You might be able to have the best of two worlds with some kind of combination of foundation repair methods. One method of repair is used for the perimeter of the home and another method is used beneath the interior. Pairing a perimeter for drilled piers or pressed piles with polyfoam under the middle are the most likely combinations.

what's the better, faster, cheaper foundation repair method?

There are potential benefits to the homeowner in using a combination approach. You may be able to use a better and more ground-penetrating method around the perimeter and a less intrusive and less floor-damaging method under the interior so that you don’t have to move out or get new flooring. Sounds like it could be a good option, doesn’t it?

The combination approach would be optimal for a homeowner who would be unduly burdened by needing to move out for one of the more intrusive, yet more ground-penetrating methods. We have often recommended something like this for elderly or physically challenged homeowners who can’t handle the pack-up and move-out process. 

Combining methods is also a great option if you’re trying to save on the expense of interior repairs but still want some support under the middle of the home vs. not getting any support beneath the interior.

The major issue is that not many foundation repair companies offer multiple methods of repair. They either do one or another. You would likely have to engage with more than one company AND they would have to *play nice* with one another a bit to get the job done. This could be a challenge, but not impossible for the motivated homeowner.

Pros of a Combination Approach

  • May be able to minimize costs and intrusiveness of interior repairs
  • Receive better benefits of ground-penetrating foundation repair on exterior
  • Balance your needs in foundation repair outcomes

Cons of a Combination Approach

  • Hard to find one company that does more than one method
  • Burden on the homeowner to engage multiple companies
  • Contractors might not cooperate with one another
  • Could be more trouble than it’s worth

How Should You Handle Interior Foundation Settlement?

Foundation problems beneath the center of your home are a bigger problem than issues that can be handled with just perimeter support. It’s a bigger problem because it’s a bigger decision in terms of expense, the possibility of needing to move out, and greater collateral costs to consider. 

deciding on foundation repair
She’s smiling but I don’t think she’s decided . . .

Interior settlement sometimes causes more glaring visual signs and more alarming functional issues for your home if active settlement is allowed to continue. If I were you, I would get the best repair I could possibly afford. This is not the time to skimp – do *something* to support the middle of your home as opposed to nothing.

Most importantly, your home should be making you happy not stressing you out, so choose what’s going to make you the most satisfied with your decision.

How to Get Started with Repairing Interior Settlement

Now that you have learned about several different options for tackling the foundation settlement affecting the interior of your home, does one option sound like the one you want? If so, fantastic! If you’re still just as undecided as you were before, you might need to spend some time identifying your top needs for foundation repair more clearly.

identify your foundation repair needs

At Anchor Foundation Repair, we want what’s best for you, even if that means sharing recommendations in another direction away from our services. After 35+ years in business, that’s just how much we want to help you get your foundation repair needs met.

For more guidance on identifying your top priorities in choosing a foundation repair company or method, check out How to Pick a Foundation Repair Company: Your Top Needs In 7 Questions.

P.S. It might also help for you to look at a deeper comparison between drilled piers vs. pressed pilings as these are the two most readily available foundation repair methods in our Brazos Valley area.