Can wet insulation be dried and kept?
Sometimes. Insulation that is only lightly damp, whose structure is intact, and whose cavity can be ventilated may dry to the readings and be kept. Insulation that has soaked through, clumped, matted or lost its shape is removed and replaced.
The test is what the insulation does when it is read, not how it looks. A batt that feels heavy and cold at the centre has taken in water, even if the outside looks fine. Loose-fill that has clumped has lost much of its performance even when it dries.
Insulation that came from a contaminated source, such as a drain backup, is usually removed, because it cannot be cleaned to a safe condition. The crew explains the decision for each area before any insulation comes out.
Why should insulation be replaced before a wall is closed?
A closed wall with wet insulation traps the moisture against the framing and the drywall. The damp can stay there for a long time, and it can support growth and damage the finishes, all out of sight. The insulation and cavity must be dry before the wall is closed.
Drywall and paint over a wet cavity look finished at first, and the problem appears later as staining, softness or a smell. The cost of opening a closed wall to find the moisture is far greater than the cost of checking the cavity first.
The crew records the readings in the cavity before the new insulation goes in, and the record shows that the wall was ready to be closed. Keep the record with the repair invoices.
Does new insulation need to match what was there?
Not always, but it should suit the space and the structure. The contractor can recommend a type that fits the cavity and the way the house is built, and you can ask for the performance of the new material to be stated in writing.
A like-for-like replacement is often the simplest choice, but the crew or the contractor may recommend a different type if the old one was unsuitable for the space. Ask why the choice was made and how it will perform in the cavity.
Keep the product details and the installation record with the house papers. A future buyer or an insurer may ask what was installed and when.
How does insulation removal affect the claim?
Removal and replacement are usually part of the repair, and the insurer decides how they are covered under your policy. The readings, the photographs and the list of removed material are the evidence for the insurer.
Keep a list of each area where insulation was removed, with its type and its condition. Photographs of the insulation as it was found are valuable, because they show why it could not be kept.
The replacement invoice should show the material and the area it covers. An insurer that asks for the scope will want to see that each area of removed insulation was replaced.
Will the house be warmer or cooler after new insulation?
It should perform as the new insulation is rated to perform, once the cavity is dry and the work is closed correctly. The crew cannot promise a change in comfort or in heating and cooling costs, because those depend on the whole house.
Insulation that is wet or compressed performs much less well than dry, fitted insulation. Replacing it restores the material, but the change you notice depends on the rest of the house, including its windows, doors and heating.
Ask the contractor what the new insulation is expected to do in your house and how that is measured. Any figure for performance should come from the product's own information, and it should be given to you in writing.