What is the process for creating a basement with no foundation?

You cannot build a basement without a foundation. The foundation walls and footing ARE the basement. So the real question is usually one of two: you have a house on a slab or crawl space and you want a basement dug under it, or you already have a basement and the foundation is failing. We are a repair and dry-out crew. We do not pour new foundations or do full new builds. What we do is keep an existing foundation standing, dry, and usable. Here is how each path goes.

Digging a new basement under a standing house

This is a heavy structural job, and it is rare for a reason. A house on a slab or shallow crawl has to be lifted or shored, the ground under it dug out, and a new foundation poured. The cost runs high and the risk runs higher. We do not pour new foundations, so this is not our lane. If a builder tells you they can dig a full basement under your finished home for cheap, slow down and get a second set of eyes.

What we CAN do once a foundation exists is the underpinning side of the structural work. If a footing is too shallow or settling, helical and push piers can carry the load. See /helical-piers/ for how that works.

Fixing a foundation so the basement is sound

Most folks who ask this question already have a basement. The walls are bowing, cracking, or letting water in, and it feels like there is “no foundation” holding it. There is. It just needs help.

Here is the order we work in.

First we look. Free inspection, free estimate, quote within 24 hours. We figure out if the problem is water, movement, or both.

Then we stabilize the structure if it is moving. A wall pushing in from NH frost heave gets carbon-fiber straps or a power brace. A sinking footing gets helical or push piers. A sagging beam or floor gets lally columns or new floor support. Plan on $850 each for carbon-fiber straps, $1,300 per brace for a power brace, $2,700 per pier for the first three, then $2,200 per pier after that for helical piers, and $1,300 to $2,500 for lally column work. A full foundation-wall rebuild or steel I-beams, we price that after we see it. There is no way to quote a rebuild off a phone call. See /structural-and-foundation-repair/ and /foundation-repair/.

If a crack is just weeping, that is the cheap fix. Crack injection, epoxy or polyurethane, runs $1,000 to $3,000. You may not need straps or piers at all. A weeping crack is usually not a structural emergency. We will tell you when it is one and when it is not.

Then we dry it out. Water pools at the foundation because the soil right against your house is disturbed backfill, the looser dirt that got put back when the house was built. It drains slow and holds water. That water finds the floor wall joint and comes in. Our fix is the Forever Dry System: full-perimeter interior drainage, a sump pump, a 12-mil wall vapor barrier, and a dehumidifier. It is 100% guaranteed to be dry for life! Waterproofing runs $3,000 to $30,000. See /basement-waterproofing/.

We do not dig up your yard for exterior waterproofing. In our field experience that fix fails in a couple of years. Interior drainage lasts. That is what we install.

Finishing the space once it is dry and solid

Only after the foundation is sound and the basement is dry does finishing make sense. We pull the permit and one of our crews builds it out, four to twenty-four weeks depending on scope. Finishing runs $30,000 to $200,000. If you need a legal bedroom down there, you need an egress window, which runs $8,000 to $15,000. See /basement-finishing/ and /egress-window-installation/.

Do not finish first. We have seen people drywall over a wet, moving wall and lose all of it. Dry and solid come first. Pretty comes last.

A note on radon. New England sits on a lot of granite, so test before you finish. If levels read at or above 4.0 pCi/L, the EPA says fix it, and 2 to 4 pCi/L is worth considering (epa.gov/radon). A mitigation system runs $900 to $6,000, and most homes land around $1,950 to $2,250 and a test is $50, credited toward the job if you move ahead. See /radon-mitigation/.

Every piece of this is backed. Read the full terms at /the-603-guarantee/.

Talk to us

Call us at 603-610-1770 or book your free inspection. We will tell you which path your house actually needs, and which parts you can skip for now.

Related questions

Can you dig a basement under my existing house? We do not pour new foundations or do full new builds. We repair and waterproof foundations that already exist. If your footing is shallow or settling, helical and push piers can carry the load. See /helical-piers/.

My basement floods but the walls look fine. Do I need foundation repair? Probably not. Water and structure are two different jobs. If the walls are not moving or cracking, you likely just need waterproofing with the Forever Dry System, not piers or straps. See /basement-waterproofing/.

Is a bowing basement wall an emergency? Sometimes. A wall pushing in from frost heave needs stabilization, carbon-fiber straps or a power brace, before it gets worse. A thin weeping crack usually is not urgent. Book a free inspection and we will tell you which one you have. See /structural-and-foundation-repair/.