Is it worth it to do exterior waterproofing of a home, and will it stop cracks and leaking in a basement?

For most New Hampshire basements, no. Digging out the foundation and coating the outside is the most expensive way to chase a leak, and from what we’ve seen in the field it tends to fail in a few years anyway. The fix that actually keeps a basement dry for good is interior drainage, and it costs a lot less than a big exterior dig. That’s $3,000 to $30,000 for our Forever Dry System. By itself, waterproofing stops leaking. It does not fix a crack that’s moving. That’s a separate structural repair.

So if you’ve been quoted a big number to waterproof from the outside, slow down. Here’s how we’d think about it.

Why we don’t dig the outside out

Exterior waterproofing means excavating the dirt all the way down the foundation wall, drying it, coating it, and burying it again. On paper it sounds right. In practice it’s the priciest path, and it leans on a coating that’s sitting in wet, shifting ground.

Nik, our wizard behind the curtain, has watched these jobs go south. The membrane gets nicked during backfill, the soil settles, the coating cracks, and water finds its way back in. We’ve seen them fail in about two to three years. That’s our own experience on real New England houses, not a number we read somewhere. So we stopped offering it. Why sell a fix we don’t trust?

The reason water shows up against your wall in the first place isn’t really the wall. It’s the dirt. The soil right next to your foundation is disturbed backfill, the loose fill that went back in the hole when the house was built. It drains slow and holds water, and our freeze-thaw winters push frost against the wall. Coating the outside doesn’t change that. You’re paying a lot to fight the ground.

What actually keeps a basement dry

Interior drainage. We run a full-perimeter channel along the inside footing at the floor wall joint, send the water to a sump pump (one 1/2 hp pump per 120 feet of drain), put a 12-mil vapor barrier on the walls, and add a dehumidifier. That’s the Forever Dry System. Water that gets to the wall hits the drain and gets pumped out before it ever pools on your floor.

It’s $3,000 to $30,000, it goes in from the inside with no big dig, and it’s 100% guaranteed to keep you dry for life! That guarantee is transferable too (conditions apply). Compare that to a five-figure exterior excavation that may not hold, and the math gets simple fast.

Will waterproofing stop the cracks?

Here’s the part people mix up. Waterproofing stops water. It does not stop a wall from moving.

If your basement has cracks, you’ve got two kinds. A crack that only weeps water and hasn’t moved in years is a sealing job, a resin injection at $1,000 to $3,000, and you’re done. A crack that’s getting wider, stair-stepping through block, or paired with a wall bowing inward means the foundation is moving. That’s structural, and no amount of waterproofing fixes it. That needs the right repair: carbon-fiber straps, a power brace, or piers, depending on what we see.

So if your worry is both water and cracks, the real answer is usually a smaller combo than a giant exterior dig. Interior drainage for the water, and a targeted structural fix only where a crack is actually moving. You don’t need the whole outside torn up to get there.

When you might not need much at all

We’ll say it plain: not every damp basement needs a full system. If you’ve got one stable, weeping crack and the rest of the floor stays dry, sometimes the move is to seal that one crack and watch it. When a full system is out of budget and the crack is dry and stable, fill it and don’t look back. We’d rather tell you to wait than sell you a load of work you don’t need yet.

A dry basement also helps the whole house. The U.S. Department of Energy’s Building America program notes that a good chunk of a home’s heat loss can come from an uninsulated, damp foundation, so drying it out pays off in more than just a clean floor.

What to do next

Get someone in to look before you spend on anything exterior. We’ll tell you whether your problem is water, a moving wall, or both, and we’ll quote the interior fix that handles it. The inspection is free, the estimate is free, and you’ll have a number within 24 hours.

Call us at 603-610-1770 or book your free inspection. We serve New Hampshire, Maine, and northern Massachusetts.

Related questions

Is exterior waterproofing cheaper than interior? No. Exterior excavation is usually the most expensive option because of the digging and re-backfill. Our interior Forever Dry System runs $3,000 to $30,000 and goes in with no big dig.

Why did my exterior waterproofing fail? Usually the buried coating gets nicked during backfill or cracks as the soil settles, and water works back in. We’ve seen exterior jobs fail in about two to three years, which is why we use interior drainage instead.

Will sealing a foundation crack stop my leak? If the crack is dry-or-weeping and hasn’t moved, a resin injection at $1,000 to $3,000 usually handles it. If the crack is widening or the wall is bowing, that’s structural and needs bracing or piers, not just sealing.

Do you waterproof crawl spaces the same way? No. A crawl space gets encapsulation, not the Forever Dry System. See Crawl Space Services.

More: Basement Waterproofing · Structural & Foundation Repair · Foundation Repair · The 603 Guarantee

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Byline: Chris Pagliccia, 603 Basement Solutions