Why does wet hardwood cup, and can it be prevented?
Hardwood cups when the moisture in the bottom of a board is higher than in the top, so the bottom swells and the edges lift. Drying the floor slowly and from beneath reduces the difference, and it prevents most cupping that would otherwise set in. Cupping that has already set can settle or need sanding.
The wood moves most across the grain, and a board that is wet on one face and dry on the other will bend toward the wet side. A floor drying at a steady rate from both sides stays flatter than one that dries quickly from the top.
Cupping is not always permanent. Some boards flatten as they dry evenly, and some stay cupped. The crew measures the floor before and after drying, so the decision on sanding or replacing is based on what happened.
Does carpet always have to be removed?
Carpet and pad that have soaked up water usually come out, since the pad holds moisture against the subfloor and the fibers cannot be cleaned to a safe standard after sewage or river water. Carpet that is damp only on the surface may be dried in place, and the crew decides after measuring the pad.
A carpet that was wet for a few hours from clean supply water may be saved, if the pad is dry and the carpet is lifted and dried quickly. Water that sat for a day or more, or that came from a river or a drain, is treated as too far gone to keep.
Where carpet is removed, the tack strip, the subfloor and the edges are checked. The carpet trade replaces it once the subfloor is dry, and the old carpet is photographed and bagged so the record is complete.
How do you dry the subfloor under a wood floor?
The subfloor is measured through the boards, and where it is wet, the affected boards are lifted and the subfloor is dried from above and beneath. Air movers are set to move air across the open area, and a dehumidifier holds the room's humidity while the subfloor comes down to its goal.
On a raised floor, the crawl space under the boards can be dried with air and a dehumidifier placed through the access. That approach dries the joists and the underside of the subfloor at the same time as the top.
Once the subfloor is dry, the boards can be reinstalled or replaced. A subfloor that stayed wet for a long time may have swelled or started to rot, and the crew reports that to the flooring trade before the boards are fixed.
What moves the scope and price of a flooring job?
The area of the floor affected, the type of flooring, the number of boards to be lifted, the amount of carpet and pad to be removed and the condition of the subfloor decide the scope. The price is explained and approved on site before the work begins, and changes are explained first.
A small area of wet hardwood with a dry subfloor is a short job. A whole room of carpet, pad and wet subfloor, with a wood floor in the next room that also took water, takes longer and adds more lifting and drying.
Furniture, built-in cabinets and transitions to other flooring add time as well. The crew photographs and moves those items carefully and notes them in the log. None of these factors becomes a figure on this site.
Can the floor be walked on while it dries?
Only in the dry areas, and not on lifted or soft boards. Walking on a wet or lifted floor can crack the boards or push them out of line. Keep to the dry parts of the house until the crew says the floor is safe to use.
Equipment on the floor, such as hoses and air movers, can be a trip hazard. Keep the paths clear of cords and be careful at the edges of the drying area where the boards may be raised.
Pets and children should be kept off the affected floor. The boards are fragile while they are drying, and a fall or a scratch can add repair work.