What we will and will not tell you. We will tell you what a pattern usually indicates and whether it warrants a proper look. We will not make structural determinations from a photograph or a description, here or anywhere on this site. Where a crack belongs in the assess category we say so plainly, because reassurance we are not qualified to give is worth nothing to you.
The Four Patterns
| Pattern | Usually means | What to do |
|---|---|---|
| Vertical / near-vertical, poured concrete | Shrinkage from curing. Very common | Seal if it leaks; monitor width |
| Diagonal from a window or door corner | Settlement. Common, often historic | Mark, date and monitor |
| Stair-step in block or brick | Settlement along the mortar joints | Monitor; assess if widening or displacing |
| Horizontal, part-way up a wall | Associated with lateral soil pressure | Get it properly assessed |
| Any crack widening measurably | Ongoing movement | Get it properly assessed |
| Any crack with displacement | One side has moved out of plane | Get it properly assessed |
The crack triage tool illustrates each pattern and explains how to establish whether a crack is actually moving — which matters more than its width.
What We Actually Do
Injection, for water through a stable crack
Epoxy or polyurethane injected under pressure fills the crack through its full depth and seals it. It is effective and durable on a crack that has stopped moving. What it does not do is address whatever caused the crack — so on something still moving, injection treats the symptom. That is fine when the movement has genuinely stopped and not fine when it has not, which is why the monitoring question comes first.
Repointing, on stone and brick
On the antique fieldstone and brick foundations common in Wolfeboro, Gilmanton, Sanbornton and the older village housing throughout the region, what presents as a crack is frequently failed mortar or a displaced stone rather than a fractured wall. The remedy is repointing, and the mortar matters enormously: lime-based, matched to the original. Hard Portland mix on historic masonry is stronger than the stone around it, which means stress and moisture find release through the stone instead — and that damage is not reversible.
Referral, where that is the right answer
For horizontal cracking, visible bowing, or anything with ongoing displacement, the correct next step is a qualified structural opinion rather than a contractor's quote. We will say so, and we would rather lose the work than give you a verdict we are not in a position to give.
- Honest triage — most cracks need sealing at most
- Injection for water entry through a stable crack
- Monitoring advice where movement is the open question
- Horizontal and displacing cracks referred for proper assessment
- Lime-based mortar on antique stone and brick
- Photographs and a written view, not a verdict over the phone
What It Costs
| Work | Typical cost |
|---|---|
| Crack injection, per crack | $400–$900 |
| Repointing, per section | Quoted by area and mortar type |
| Foundation repair, average | ~$5,000 (typically $2,000–$8,000) |
| Underpinning | Around $25,000 |
The vast majority of what we are called to look at needs the first line, not the last. It is worth saying that plainly, because the gap between them is where anxiety lives.
Crack Questions
Is my crack serious?
Most are not. Vertical hairlines in poured concrete are usually shrinkage. What warrants proper assessment: horizontal cracks part-way up a wall, cracks visibly widening, and cracks with displacement. The triage tool walks the patterns — as guidance, not a determination.
How do I know if it is getting worse?
Mark each end with a pencil line and the date, measure the width, photograph it with something for scale, and look again in three months and after a wet spring. Movement is what matters, and one observation tells you nothing about movement.
Can I fill it myself?
Hardware-store compounds will cosmetically fill a crack and will generally fail within a year or two. For water entry through a stable crack, professional injection is the durable answer. For anything in the assess category, filling it is actively unhelpful — you have hidden the evidence you would need to judge movement.
Does a crack affect the value of the house?
An unexplained crack worries a buyer more than a documented one. A photographic record showing it has not moved in three years is genuinely useful during an inspection, which is another reason to mark and date it now rather than later.