What is foundation waterproofing?

Foundation waterproofing is the work that keeps groundwater out of the below-grade part of your house, mainly your basement or crawl space. Done right, it does not just slow water down. It gives the water a path to a sump and out, so the space stays dry for good. In our basements we do that from the inside with the Forever Dry System, 100% guaranteed to be dry for life!

Here is the plain version. Your foundation walls sit in the ground, and water in that ground wants in. It comes through cracks, along the floor wall joint where the wall meets the slab, and up through the slab. Waterproofing stops all three.

Why does it show up? The soil packed against your foundation is disturbed backfill, the looser dirt put back when the house was built. It drains slow and holds water, so after a hard New England rain or spring thaw, water sits against your walls. Then NH frost heave pushes those walls inward over the winter.

You can fight it outside or inside. Outside means digging up the dirt around the foundation and coating the wall. We do not do that. Nik has watched those exterior fixes fail in about two to three years once the ground settles and the coating cracks. That is our field experience, not a promise about every job. Interior drainage is the fix that holds.

So inside is where we work, with the Forever Dry System. We cut a channel around the inside perimeter of the floor and lay full-perimeter interior drainage in it, carrying water to a sump pump sized at 1/2 hp per 120 feet of drain. A 12-mil vapor barrier on the walls drops wall seepage straight into the drain instead of across your floor, and a dehumidifier dries the air left behind. The basement stays dry.

One thing to keep straight. The Forever Dry System is for basements only, not crawl spaces and not foundation cracks. A crawl space is crawl space encapsulation, built different for that tighter space. A cracking or bowing wall is structural and foundation repair. Do not let anyone sell you one system for all three.

You may not need the full system. If you have one weeping crack and a dry floor everywhere else, sometimes a crack injection is the whole fix, not a perimeter drain. No sense putting in a full system for a crack an injection seals. We will tell you when we look.

What it costs. Basement waterproofing in New Hampshire runs $3,000 to $30,000, depending on how many feet of wall you have, how much water you take on, and whether you need extras like a backup pump. A single crack injection is its own smaller number, $1,000 to $3,000. You get the figure in writing within 24 hours, so you are not guessing.

The backup matters. Our backup sump is a battery unit, so it keeps pumping when the power goes out, which around here is exactly when the storm is dumping water against your foundation. A charged battery moves about a residential pool’s worth of water, roughly 15,000 to 20,000 gallons, before it runs down. (Source: pool-volume figures, USGS.)

A dry basement is worth real money too. The Insurance Information Institute notes water damage is one of the most common home insurance claims, and a flooded basement is a fast way to get there. Keeping water out is cheaper than rebuilding what it ruined.

What this means for your home

The Forever Dry System carries a full transferable lifetime warranty, conditional so it stays good as long as no other contractor or owner touches the work. The sump pump system is warrantied 3 years, batteries excluded, and the dehumidifier 5 years.

We have done this for 5,000+ homeowners across New England and self-perform with our own crew. Angel runs our waterproofing side and has seen every kind of wet basement there is.

Ready to look at it?

We will come out, find where the water is coming from, and tell you whether you need the full Forever Dry System, a single crack injection, or something else. The on-site inspection and written estimate are free, and we get you a quote within 24 hours.

Call us at 603-610-1770, or book your free inspection. We also back every job with the 603 guarantee.

Related questions

Is interior or exterior foundation waterproofing better?

For most New England homes, interior drainage is the fix that lasts. Exterior waterproofing means digging up the foundation and coating the outside wall, and in our field experience those coatings tend to crack and fail in about two to three years once the ground settles around them. Interior drainage catches the water once it is inside, carries it to a sump, and pumps it out. Our Forever Dry System works that way, and it is guaranteed to be dry for life.

Does foundation waterproofing fix a crack in my wall?

Sometimes that is all it takes. If you have a single weeping crack and the rest of the basement is dry, a crack injection with epoxy or polyurethane may seal it, and that runs $1,000 to $3,000 with a 10-year warranty. But if the crack is from a wall that is bowing or shifting, you need structural repair first, like carbon-fiber straps or piers, before you waterproof. We will tell you which one it is when we look.

How much does basement waterproofing cost in New Hampshire?

Basement waterproofing runs $3,000 to $30,000, depending on how many feet of wall you have, how much water you take on, and whether you add a backup pump. A small basement with one wet wall sits on the low end. A full perimeter system with a backup battery and dehumidifier runs toward the high end. We give you a written quote within 24 hours, and the Forever Dry System carries a full transferable lifetime warranty.

Related answers: More foundation answers · If someone sealed a basement crack completely with liquid sealant, is the foundation problem fixed? · What are the pros and cons of a stone foundation? · What is the difference between helical piles and push piers?