Most foundation cracks are not an emergency. Some are. The job is telling which one you have, and that is what the free inspection is for. Crack repair at 603 runs $1,000 to $3,000.
Which cracks should worry you?
Rough guide, and it is a guide, not a diagnosis:
- Thin vertical cracks are the most common thing we see and usually the least alarming. Concrete shrinks as it cures and it has to give somewhere.
- Horizontal cracks are the ones to take seriously. A horizontal crack in a foundation wall can mean the wall is being pushed on from outside.
- Stair-step cracks in block walls follow the mortar joints and can point to movement.
- A crack that is wider at one end than the other suggests something is moving rather than just shrinking.
- Any crack that is actively leaking needs handling regardless of shape, because water gets in and does its own damage.
If you can fit a quarter into it, or it has visibly changed since you first noticed it, call somebody. Us or anyone.
How we fix them
For a non-structural crack that leaks, injection fills the crack through its full depth and seals the path the water was using. For a structural crack, epoxy injection restores the bond across it. Where a wall needs real reinforcement, carbon fiber straps or a power brace do that work, and those are different jobs with their own prices.
What we do not do is smear something on the inside and call it fixed. A surface patch on a leaking crack hides it for a season.
When we tell you not to buy
Sometimes a homeowner is bracing for a full system and what they actually need is one crack filled. When a full system is out of budget, fill the crack and don’t look back. We will tell you when that is the situation, and we would rather do the small job right than talk you into the big one.
The reverse is also true. If you have got water coming in at the floor wall joint all the way around, filling one crack is not going to solve that, and we will say so.
The warranty
Non-structural crack injection carries a 10 year warranty on leakage through the treated area. Structural epoxy injection carries 10 years on the structural bond. Wall stabilization carries 25 years against further inward movement within design tolerances.
Read that first one carefully. Ten years on the crack we treated not leaking is not the same as ten years of a dry basement, because the crack we filled may not be the only way water gets in.
Questions we get
Can I fill it myself from the hardware store?
You can, and for a hairline shrinkage crack that is not leaking it may hold fine. For anything structural or anything wet, a surface product is a temporary measure.
Will it crack again in the same place?
A properly injected crack is not usually the one that comes back. New cracks elsewhere can happen as a house keeps settling.
Do you fix cracks in a slab floor?
We look at them. A floor crack and a wall crack are different problems.
How long does it take?
Most crack repairs are a few hours.
Crack shapes, and what they usually mean
| What the crack looks like | What it usually means | How urgent |
|---|---|---|
| Thin and vertical | Concrete shrinkage as it cured | Usually low. Seal it if it leaks |
| Horizontal across a wall | The wall may be under pressure from outside | Get it looked at |
| Stair-step through block joints | Movement following the mortar | Get it looked at |
| Wider at one end than the other | Something is moving, not just shrinking | Get it looked at |
| Any crack actively leaking | Water has a path in | Handle it regardless of shape |
| Hairline, dry, unchanged for years | Often nothing | Watch it. Note the date |
How the job runs
Somebody looks at the actual crack. Shape, width, whether it is wet, whether it lines up with anything else the house is doing. That is a short visit and it is free, and it is the only honest way to tell a shrinkage crack from something that matters.
You get told which one you have got. If it is the small one, we will say so, and we would rather do the small job right than talk you into a system you do not need yet.
The repair itself is usually a few hours. Injection fills the crack through its full depth rather than skinning over the face of it, which is the difference between a repair and a cosmetic patch that looks fine until the next wet spring.
If the wall needs real reinforcement, that is a different job with its own price and its own timeline, and we will lay that out separately rather than folding it into a crack quote.
What is actually under Londonderry
Londonderry sits across four USGS quadrangles, all New Hampshire: Derry, Manchester South, Nashua North and Windham. Published surficial maps exist for all four. Bedrock is a thinner record, with a 1:24,000 map published only for Windham.
Four bedrock units underlie the town, including the Berwick Formation of the Merrimack Group and the Massabesic Gneiss Complex. The USGS notes that the well-bedded Berwick is exposed in roadcuts near the interstate in Londonderry, which is to say you can see it on the drive.
Drainage, by the numbers
Of the town’s mapped soils, about 56 percent are well drained and 11 percent excessively drained. But 12 percent are very poorly drained and another 3 percent poorly drained, so roughly one acre in seven is ground that holds water. The town’s own plan reports 52 percent of its soils in Hydrologic Soil Group B and about 22 percent in Group C.
The restrictive layers are the detail that matters for a foundation. Hollis soils record lithic bedrock at a representative depth of about 38 to 41 centimetres, Chatfield at about 76, with rock outcrop at zero. Where compact till is the restriction, water moving down stops there and moves sideways instead.
Shallow bedrock and dense till do the same thing to water. They send it somewhere else, and somewhere else is often the nearest foundation.
Where the town is dry, and where it is not
Over 93 percent of Londonderry is FEMA Zone X, which is minimal flood risk. The higher-risk ground is specific: upstream of the Little Cohas Brook Reservoir, upstream of Kendall Pond, near the Beaver Brook headwaters. Wetlands cover about 2,501 acres, roughly 7 percent.
The town is 72 percent bedrock aquifer and 24 percent stratified drift. Impervious cover is 10.3 percent, just over the 10 percent mark at which stream quality is generally considered impacted.
Being in Zone X does not mean a basement stays dry. Most of the wet basements we see have nothing to do with a river and everything to do with water in the soil beside the wall. That is a different problem with a different fix, and it is what the inspection is for.
Aquifers, wetlands and the shape of the town
Londonderry has four major stratified drift aquifers, and the town’s plan places them primarily near the municipal borders. The bedrock is recorded by the town as 82 percent metamorphic and 18 percent plutonic igneous, with the plutonic ground concentrated in the northwest corner.
Wetlands run to roughly 2,501 acres, about 7 percent, and about 60 percent of that is freshwater forested and shrub rather than open marsh. Forested wetland is easy to miss from a driveway and it is still wetland.
The town is drained east by Beaver, Indian and Black Brooks, and west by Little Cohas Brook and its neighbours, all within the Lower Merrimack River Basin. Three of its watersheds already carry impervious cover above the 10 percent mark.
What our customers say
603 basement solutions was one of 5 companies I evaluated for a large eye beam replacement, the job was complex and required engineering plans and the town’s involvement. 603 had the best price and came off the most professional by a large margin. The job took a total of 2 months because of town delays but when it came to their part they knocked it out of the park. Extremely happy with my decision and would recommend them to anyone who needed structural work done.
V, Google review, 5 stars
That is one of more than 240 Google reviews. We would rather you read them than take our word for anything on this page.
Related pages for Londonderry
- Basement waterproofing in Londonderry
- Structural and foundation repair
- Which foundation cracks matter
- Every town we cover
- Who you would actually be dealing with
- Basement waterproofing
- Straight answers to basement questions
Book a free inspection in Londonderry
Somebody comes out, looks at the actual space, and tells you straight what it needs and what it does not. You get a written number for a defined scope. No two hour pitch, because we would rather be at the next house.
If you are looking for a team that isn’t going to treat you like another number, we would be happy to give you an estimate free of charge. We don’t cut corners. We stand behind our work. We care.
Call 603-610-1770 or book your free inspection. We cover Londonderry and the surrounding towns from our shop in East Kingston, New Hampshire.
Common questions about foundation cracks
- We have a horizontal crack in a support beam in the basement. Is it serious?
- We just got a home inspection done and saw some cracks. What do they mean and do we need to fix them?
- What are some ways to fix a sinking foundation of an old house?
- What are the advantages of a helical pile?
- What are the best methods for repairing a cracked foundation?
- What are the common warning signs that indicate a foundation problem?
- What are the different types of underpinning?
- What are the pros and cons of a stone foundation?
- What are the reasons and purposes of underpinning service?
- What are the signs of an unstable foundation, and what damage may it cause?
- What can be done to fix a house’s foundation after it is built?
- What can cause a crack between staircase and its wall?
More 603 services in Londonderry
- Basement Waterproofing in Londonderry, NH
- Basement Finishing in Londonderry, NH
- Crawl Space Encapsulation in Londonderry, NH
- Radon Mitigation in Londonderry, NH
