Add a vapor barrier
Adding a vapor barrier entails adding an underlayment below the subfloor in order to keep ground moisture from seeping into the subfloor. If you suspect that the moisture issues are caused by water vapor coming from the ground, this can be an excellent solution.
Therefore, because concrete is porous, it's a good idea to install a vapor barrier over your concrete subfloor before installing your flooring. This way you can stop the vapor drive of water upward to your floors, protecting them from any damage (source).
One solution to help protect the sub-floor from rainwater damage during construction is to use LP® TopNotch® 350 Durable Sub-Flooring. What is LP TopNotch 350 Durable Sub-Flooring? LP TopNotch 350 Durable Sub-Flooring is an OSB sub-flooring designed to reduce the impact of moisture during construction.
It's the combination of high wood moisture content and wood-destroying fungus that causes most wood rot. But what causes high wood moisture content and the growth of wood-destroying fungus? These causes of wood rot arise because of long-term exposure to moisture.
The national cost range for replacing a subfloor is between $600 and $2,500. Most homeowners pay around $1,600 for a 200 sq. ft. area in a kitchen or living room using OSB board.
Homeowners insurance generally covers water damage that's sudden and accidental. For example, if a pipe bursts or a washing machine overflows and damages your floor, you may be covered. But if the water comes from flooding, standard homeowners insurance typically won't cover it.
You can seal a subfloor using a sealant specifically designed for subfloors, such as a penetrating sealer or a moisture barrier. Penetrating sealers are typically made from a wax or oil-based formula that soaks into the wood, protecting it from moisture and rot.
A wet subfloor doesn't always need to be replaced, but it must be thoroughly dried and assessed for damage. Use fans and dehumidifiers to dry it out. If the subfloor is swollen, warped, or has mold growth, replacement is necessary.
Moisture and mold protection
An underlayment that offers a vapor barrier is essential to protect any flooring installed over a subfloor that emits moisture, like concrete. A thin foam underlayment made of polyethylene or polypropylene usually works best.
Very often, particularly in a below-grade installation on a concrete basement floor, a vapor barrier is recommended in addition to the underlayment. That vapor barrier would go between the subfloor and the underlayment.
Both are designed to keep moisture out of your home and can be made from various materials. But there are a few key differences, the most apparent being that moisture barriers are better at keeping out liquids, and vapor barriers are better at keeping out water in its gaseous state.
The barrier must be installed directly onto the surface of the subfloor. Use a sealing tape to seal the rows securely together. The installation should be in the opposite direction you plan to install the underlayment to reduce seams, in the same direction of the final floor.
Epoxy. Epoxy sealers are usually the preferred method of sealing and waterproofing plywood. Epoxy doubles as an adhesive, which gives an additional layer of strength plus protection for the wood, helping it to last even longer. It can double as a primer too, if the wood is to be painted after sealing.
Subfloor typically lasts 30 years or more, but if it is consistently exposed to moisture you may need to replace it sooner.
Yes. Hardwood flooring is quite sensitive to moisture and it's always worth adding a moisture barrier during installation. It is a necessity with concrete subfloors and damp areas, but water-resistive underlayments should be considered with other subfloors as well.
Liquid waterproofing is a technology which involves applying liquid to a surface to prevent water intrusion. The liquid used to provide this waterproofing layer can vary between products. This has given rise to a number of different liquid waterproofing systems.
Unfortunately, dry rot isn't covered under most building insurance policies. This is because it's seen as a gradual deterioration rather than sudden, accidental damage. Here's the reasoning: Insurers view dry rot as a consequence of long-term issues like poor ventilation or dampness.
Typically covered: losses caused by water abruptly leaking from a pipe inside the home, frozen/burst pipe if reasonable care is used to maintain heat in the home, water backing-up through a sewer or drain (with Back-up of Sewer or Drain endorsement) and water damage to your home caused by ice dams.
Replacing a subfloor may seem like a daunting task, but with the right tools, materials, and know-how, it's a project that can be tackled by DIY enthusiasts or professionals alike.
Given the complexity of subfloor repairs, you should really stick with a carpenter for this project. But if you want to install a new subfloor or underlayment over sound floor joists, hire a local flooring contractor for this step.
When Should You Replace Subfloors? There are many signs that your damaged subfloor should be replaced with a new subfloor. These include squeaks and other noises, cupping or warping, cracked or popped tiles, sagging or unevenness, the smell of mold or mildew, or bubbling tile.