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 Nashua’s own records say about water
Nashua does not guess about this, and neither should we. The city keeps its own numbers, and they are worth knowing before you spend money on a basement.
Roughly 20 percent of the city runs on combined sewers, which carry sewage and stormwater in the same pipe, and the city notes that some of those sewers date back to the 1880s (City of Nashua Stormwater Funding Feasibility Study, 2011). The drainage network they are attached to is large: 8,069 catch basins, 130 miles of drainage pipe, 807 outfalls, and about 400 catch basins cleaned a year, which is roughly five percent of them.
The city also names the places that give trouble. Old Maid’s Brook at Shelley Drive and Browning Avenue “currently overtops the road creating a hazard.” Harris Brook at Northeastern Boulevard does the same. Manchester and Charlotte floods “due to a lack of a drainage system” (same study, capital improvement list).
And when it rains hard here, basements are what fills. In the 11 September 2023 event, Nashua Emergency Management recorded about a dozen reports of flooded basements, with 2 to 6 inches of rain reported between Hollis, Nashua and Hudson (City of Nashua Hazard Mitigation Plan Update, 2024).
The ground under the city
Four watersheds sit inside Nashua, all draining to the Merrimack, and the city’s floodplains run with Pennichuck, Hale, Hassel and Salmon Brooks as well as the two rivers (Nashua Natural Resources Inventory and Conservation Plan, 2006). The land falls from Gilboa Hill at 426 feet to about 90 feet at the Merrimack in the southeast corner.
Gilboa Hill is not just high ground. The USGS records it as one of several thick-till-cored drumlins in the area. Till is dense, mixed glacial material, and it drains slowly. Down near the rivers the soils are different again, with Windsor and Hinckley types among the largest mapped units in this survey area (NRCS soil survey NH601).
So a house on Gilboa and a house off Main Dunstable can have genuinely different water behaving genuinely differently, in the same city, in the same storm.
That is the regional picture. It is not a reading of your lot, and we are not going to pretend it is. Two houses on one street can sit on different material. The free inspection is where we find out which one you have.
Flood insurance and the streets that carry water
Nashua joined the National Flood Insurance Program on 15 June 1979, and as of January 2017 held 155 policies in force against $43,548,100 of insurance, with 31 paid losses. The NOAA gauge on the Merrimack at Nashua sets minor flood stage at 18 feet and records a crest of 41.3 feet in March 1936.
Several road crossings sit inside the floodway itself: Main Street at the Nashua River, Allds Street at Salmon Brook, Manchester Street at a floodway crossing, with Pine Hill Road inside the 0.2 percent floodplain. Salmon Brook, which takes in Hassell, Old Maid’s and Hale Brooks over its 6.5 miles, is listed impaired for E. coli with the source recorded as illicit connections to storm sewers.
None of that is a verdict on a specific street. It is the shape of how this city moves water, and it is the background we are working against when we look at a basement here.
What our customers say
603 basement solutions came highly recommended by a general contractor we know and man did they deliver. We hired them to do a large and complex project with structural components and waterproofing. They finished the project on time and for the same price the quoted us. They were all professional and communicated great, I highly recommend them!
Benjamin Mazza, 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 Nashua
- Basement waterproofing in Nashua
- 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 Nashua
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 Nashua and the surrounding towns from our shop in East Kingston, New Hampshire.
Common questions about foundation cracks
- I have a leak in my basement wall with a crack less than a quarter inch wide. Injection or more extensive repair? Best route?
- If a house has a major cracked foundation, is it better to rebuild or repair the foundation?
- If a house’s foundation is rebar and concrete, how serious is foundation damage when it shows up?
- If someone sealed a basement crack completely with liquid sealant, is the foundation problem fixed?
- If you have a rotting sill plate or rim joist, is that simple to fix?
- Is a cement basement crack expected in a 2-year-old home?
- Is a stair step hairline crack something to worry about?
- Is foundation repair worth the expense in a house?
- Is it a good or bad idea to buy a 1984 home which has had foundation repair done?
- Is it a good practice to put a coat of waterproofing on my foundation?
- Is it better to put down a concrete slab or use concrete blocks for a foundation repair?
- Is it okay to buy a house with foundation problems?
More 603 services in Nashua
- Basement Waterproofing in Nashua, NH
- Basement Finishing in Nashua, NH
- Crawl Space Encapsulation in Nashua, NH
- Radon Mitigation in Nashua, NH
