Can You Put a New Foundation Under an Existing Home?

As a homeowner, you would expect to replace parts of your home. Maybe you’ll purchase a new roof or new windows. But a new foundation? That seems unheard of. It’s the foundation holding everything up, for goodness’ sake!

It would be nice if the finer purchases in life would last forever. However, this isn’t the case. The same goes for the most important parts of your home. With age and deterioration, your foundation is no exception.

Dalinghaus Foundation Repair has completed more than 2,000 foundation projects since 2011, working in Southern California, Arizona, and Nevada. Our scope is repair and stabilization of the foundation a home already has, using helical piers, push piers, polyurethane lifting and void fill, and structural repair in the crawl space and framing. Building a replacement foundation is a different trade, designed by an engineer and built by a general contractor.

That distinction matters for the question in the title, so this article covers both sides of it: when a new foundation actually gets specified, what that work involves, and why most homes that feel like they need one need stabilization instead.

Why Should Foundations Be Strengthened?

Foundations for new homes are constructed under today’s current codes. Concrete, stone, or brick used in the past fails in comparison. The amount of rebar used and the depth of the footings tend to be incorrect.

The footing is old and made with materials that deteriorate due to water, foundation movement, the size wasn’t correct, or it didn’t have rebar.

Different soil compaction standards have been implemented compared to the 1960s.

How Do I Know If My Foundation Needs Replacing?

Hopefully, this isn’t the case for you. More often, one section of the footing needs repair, not the whole thing. This is due to concrete spalling or blown-out rebar.

Concrete spalling, This is when concrete starts to flake off. This can be due to subpar concrete, the concrete curing process being incorrectly done, corrosion due to water exposure, or oxidizing rebar. This will look like your concrete is trying to look like the Berkley Pit.

Check out our article on concrete spalling to understand this concept more in-depth.

Blown-out rebar, This is always due to the rebar being exposed to moisture in some way, causing oxidization (a.k.a. rusting). Oxidizing causes the rebar to expand.

Sometimes, water will get through the cracks in your concrete. That said, concrete is porous. Dry concrete creates small capillary tunnels smaller than a strand of your hair. Water will navigate through those tunnels and make contact with your rebar.

This is why you want to make sure you have proper drainage. You want to make sure those water puddles hang out for too long like it hasn’t left after partying too hard.

Can You Put a New Foundation Under a Home?

It can be done, on a slab or a raised foundation. The old foundation comes out and a new one is built in its place, under an engineer’s design and with the house temporarily supported the whole time.

You’ll see this more often with raised foundations compared to slab-on-grade.

A new foundation needs to be constructed for issues such as age, deterioration, and settlement.

Putting in a New Foundation for a Raised Foundation

You would first go into the crawlspace and shore up the home, meaning the house is temporarily held up for construction. You don’t want your home falling on someone and having them end up like the Wicked Witch of the East.

This involves running girder beams along with posts and pads around the outside of the home.

Next, a production crew starts digging to remove the old footing as the house is shored up. A new cripple wall would be built, or the footing is formatted to be put in place using rebar.

The concrete pouring can be done in sections or all at once if the entire home can be stabilized.

The home can also be raised above its original placement before the new footing is built, though lifting a house that far adds real risk of damage to the structure above.

Putting in a New Foundation for Slab-on-grade

This is less common compared to their raised counterparts. Usually, a sister footing is made, which involves putting a new footing under the old.

You would have to dig and use sacrificial jacks, like car jacks, to hold up the slab from underneath.

The footing is taken out in sections as everything else is held up. The footing is formed via rebar with the backend reinforced by dirt. Concrete is then poured from there.

What About Historical Homes?

In some cases, new footings need to be put on the interior while making the exterior appear as when it was originally built.

The exterior needs to make the historic home look like it wasn’t ever touched by construction.

How Long Does It Take to Replace a Foundation?

Putting in an entirely new foundation can take around four weeks minimum.

Larger equipment like an excavator can be used to dig will be used assuming there is enough space. That said, it can be done by hand, which can add to the project time.

Cost of Replacing a Foundation

Replacement is priced by the general contractor doing the build, from the engineer’s drawings. The size of the home, how much of the footing is involved, and how easily equipment can reach the work all move the number, which is why nobody can quote it from a photo.

Needing a new foundation is more common in older homes or cities. New homes usually don’t have to worry about this.

There have been homes built in the 1940s that have footings that still look young. Don’t stress yourself out about needing a new footing. A new foundation is only necessary if it’s too deteriorated or compromised.

What Dalinghaus Does Instead

Full replacement is rare, and it is not our trade. What we see far more often is a foundation that is sound enough to keep, sitting on soil that stopped carrying it. That is a repair, and it is the work we do:

• Push piers and helical piers carry the weight of the house past the soil that moved and down to ground that holds, and where the structure allows it, they can lift back toward level.
• Polyurethane fills voids under a slab and raises settled concrete back into position.
• Crawl space and framing repair replaces failed posts and pads and reinforces the wood supports carrying your floors.

If the evidence at your property genuinely points to a replacement rather than a repair, we will tell you that plainly and point you toward the engineer who needs to design it. Selling a homeowner the work we happen to carry is not how we want to be in business.

Two things worth reading alongside this: how your home handles moisture, because water is behind most of the deterioration described above, and our guide on why soil compaction matters, because compaction is what decides whether the ground under a footing keeps doing its job. Excessive irrigation belongs on the same list, since watering hard against the house keeps the soil there wet year round.

If you’re worried about your foundation, have it evaluated before you plan around a number. Dalinghaus Foundation Repair can do a free 60 to 90 minute foundation evaluation.

Schedule a Free Evaluation

Foundation movement is easier to judge in person than from a photo. Schedule a free evaluation and a Dalinghaus specialist will walk the property with you and explain what the evidence shows.