Four kinds of trouble, and what each repair involves
Most crawl spaces that need work have more than one of these at once.
- Standing water
- First find where it enters: a low corner, the access door, a plumbing leak or ground water rising after long rain. Roof and surface water are redirected outside. Water that still arrives is collected in a shallow trench and pumped out from a basin.
- Fallen insulation
- Wet fiberglass does not recover. It is bagged and removed. What replaces it depends on the plan: new batts if the space stays vented, foam board on the walls if it will be sealed.
- Damp wood
- A moisture meter shows how wet the joists and beams are. Sound wood is dried by drying the space. Soft sections are cut out or reinforced with new lumber alongside.
- Sagging floor
- A beam may have lost a support or a pier may have sunk into wet soil. Added posts on proper footings can take up the load. If masonry walls are cracked or leaning, that is a structural question for an engineer or a foundation specialist, and outside what these pages cover.
The order that saves doing work twice
Stop the water coming in. Remove what is ruined. Mend the wood. Then decide whether to seal the space. A company that proposes a liner over wet soil and soft joists is skipping steps, and you would be paying to hide the problem.
Ask for photographs from under the house, taken before and after. You should not have to crawl in to know what was done.
Things a homeowner can check from outside
- Do the gutters overflow, and do the downspouts carry water several feet from the wall?
- Does the soil slope toward the house anywhere, especially at the access door?
- Does the dryer vent to the outdoors, or does the hose end under the floor?
- Is the water meter turning with every tap closed? That points to a supply leak, and a plumber.
Before you agree to repairs
- Which pieces of wood will be replaced, and which only treated or left to dry?
- Were moisture readings taken, and can you see the numbers?
- If posts are added, what do they stand on?
- Is debris removal and disposal part of the price?
- What is not included that the company thinks you will need within a year or two?
Repair questions
Can the crawl space be repaired without encapsulating it?
Yes. If the water came from one cause, such as a missing downspout or a leaking pipe, fixing that and replacing the damaged material can be enough. If the damp is from summer humidity, it will return unless the space is closed and dried.
Is the growth on my joists dangerous?
A website cannot tell you. What is certain is that it grows on wood that stays damp, so lasting control means drying the space. Ask the company exactly what cleaning it offers and get that in writing.