The three questions behind every guide
Every guide on this site is built around the same three questions, because they are the ones a homeowner needs answered in order.
- Is this serious? We compare what you see with published thresholds and known warning signs.
- Why is it happening? We explain the likely cause, because a repair that ignores the cause rarely lasts.
- What will fixing it involve and cost? We list the options, their limits and sourced price ranges.
How we rank sources
Not all sources carry the same weight. Below I am sharing the order we use when two sources disagree.
| Rank | Source type | Examples | We use it for |
|---|---|---|---|
| 1 | Building codes and government agencies | IRC, US EPA, FEMA, HUD | Rules, safety and health guidance |
| 2 | Industry standards and technical bodies | ACI, NRMCA, NAHB, BRE, ASHI | Thresholds and good practice |
| 3 | Universities and research reports | Extension services, DOE studies | How problems behave, and what works |
| 4 | Named cost publishers | This Old House, Fixr, Modernize | Price ranges, with source and date |
| 5 | Forums and search questions | Reddit, "People also ask" | What readers want to know, never as evidence |
As the table shows, forums tell us what to answer, but they never supply the answer. Contractor marketing pages are not used as evidence for a number. If sources disagree, we say so and show the range.
How we set verdicts
Our guides usually sort a problem into three levels. Below I am sharing what each level means.
- Normal: The sign falls within published limits, or it has a harmless known cause, and it is not changing.
- Monitor: The sign needs measuring or a simple fix, and it needs rechecking over time.
- Call a professional: The sign points to structural movement, a safety risk, or something that can't be judged from a guide.
We lean toward caution when a problem could affect the structure or someone's safety. We also say "leave it alone" when that is the honest answer, because an unnecessary repair is a bad outcome too.
How we use thresholds
A threshold is a reference point, not a guarantee. Below I am sharing the main ones we use, and where they come from.
| Measurement | Reference point | Source |
|---|---|---|
| Masonry crack width | Over 1/4 inch is an item for repair | NAHB |
| Poured wall crack width | Over 1/8 inch, in a typical builder warranty | NRMCA CIP 7 |
| Basement wall movement | About 1/2 inch inward is potentially serious | ASHI Reporter |
| Crawl space humidity | Below 60% relative humidity | US EPA guidance |
| Wood moisture | Below about 20% | USDA Forest Service research |
| Drying after a leak | Within 24 to 48 hours | US EPA and CDC |
As the table shows, each number has a named source. No single number decides a case. Direction, pattern and change over time matter as much as size, so we teach you to read all of them together.
How we build cost ranges
Our prices come from published cost data, and we name the source and date beside the figures. Below I am sharing how we handle them.
- Ranges, not single prices: Real prices depend on access, soil, region and damage.
- Named sources: Different publishers give different figures, and we don't blend them into a number of our own.
- US dollars by default: Prices are US figures unless a guide says otherwise.
- Worked examples: An "Example" shows the math on a made-up house, so your own total will differ.
We don't take prices from contractors who want a listing, and no company pays to change a range. For more on funding, read our advertising disclosure.
What we don't do
A guide can teach you how to read a problem, but it can't inspect your house. Below I am sharing the limits of our method.
- No site visits: We don't inspect properties, and we never claim visits that did not happen.
- No lab testing: We don't test products or materials ourselves.
- No individual diagnosis: We can't review photos or reports of your property.
- No contractor recommendations: We don't recommend or rate specific companies.
Read our disclaimer for the full limits of this information. To suggest a better source or report a figure that has changed, please contact us. You can also explore the foundation verdicts and guides on our homepage.