Insulation Got Wet | Can You Still Install It?

Moisture is a well-known enemy of every home. Mold is readily linked to the presence of this moisture, but when it comes to insulation, the continued function of the material is also called into question.

To install wet insulation is to ask for problems. However, not all wet insulation needs to go into the bin.

Wet insulation should not be installed. Wet insulation has reduced functionality and poses a risk for mold growth. Concealed in the housing structure or attic, wet insulation will not dry or will not dry fast enough.

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Insulation Must Be Dried Before Installation

Wet insulation can reduce the material’s R-value. Since R-value measures the ability of a material to impede heat transfer, this is crucial to the sole function of insulation.

This means that installing wet insulation should not be considered.

But insulation can still be dried and then installed, depending on the insulation material, what made it wet, drying time, and whether or not the moisture caused compression.

Types Of Insulation

The main types of insulation are fiberglass, cellulose, mineral wool, natural fiber, plastic fiber, foamboard, and spray foam.

Insulation Types | All You Need to Know

Fiberglass, mineral wool, plastic fiber, foam board, and spray foam insulation are not absorbent. However, water can still penetrate the air pockets that exist between the individual fibers or particles.

Cellulose insulation, as well as other types of natural insulation, are water-absorbent, which means that the fibers and particles actually take moisture into their structures in addition to moisture filling the spaces in between.

These absorbent insulation materials are less likely to be reusable after getting wet, although it can still depend on some of the other factors.

Can Depend on What Made It Wet

Another factor to consider is the cause of the wetness and what that means for the longevity of your insulation.

If your insulation is wet because it was exposed to water leaks or rain or snow, then you have a better chance of getting it back to a usable state by drying it out. The cleaner the water, the better.

Water contaminated with something like sewage would render the insulation too great a health risk to be installed, even if it dried quickly and properly.

If chemicals of any kind, such as cleaning products, paint, and thinners, were to be the cause of the wetness, then even if it dries, the insulation is now compromised and should not be used.

Chemicals can make it more flammable, degrade the fibers/particles, or make it a source of VOCs, which can evaporate into the air and pose a health risk.

In addition, if the insulation were to be wet with oily substances, then the chances of it drying out properly are reduced, and the oil can also make it a greater fire risk.

Drying Time Can Make a Difference

Drying time is the key factor when it comes to installing wet insulation. The reason is that the longer the drying time, the higher the chances of mold growth.

Mold requires moisture to establish itself and grow, often finding enough organic materials in the water to feed on without needing the substrate on which it is growing.

The longer insulation is wet, the greater the chances of mold spores coming into contact with it.

In addition, with certain insulation types, the longer they are wet, the more they break down to provide food for the mold to feed on.

The type of insulation factors into this equation because some types are less mold-resistant than others.

Fiberglass insulation is an example of inherently mold-resistant insulation. However, if this insulation is exposed to moisture, mold can form on its paper backing.

Pink fiberglass insulation installed on the walls.jpg

Insulations that have a more natural makeup, like cellulose, are more susceptible to mold. While they are usually treated with chemicals to reduce the likelihood of this growth, the fact that the material is a good food source for mold means that it is still more vulnerable.

In addition to the negative health effects associated with mold, it can also damage the insulation and reduce its effectiveness.

Guidelines from industry and manufacturers usually specify a drying time of between 24 and 48 hours. If the insulation doesn’t dry within this timeframe, you will more likely need to replace it.

Did the Insulation Also Get Compressed?

The thickness and “fluffiness” of insulation are important to its effective function. The weight of water may compromise both of these.

In some cases, the compression may be temporary, and the insulation will bounce back to its pre-wetted state.

In other cases, however, it may not recover its original thickness.

Studies have indicated that wet and/or compressed insulation may reduce its performance by about 40%.

This reduced thermal performance, or lack of thermal protection, will cause energy inefficiency in your home, which has real effects on comfort and costs.

In severe water or moisture damage conditions, you should consult a professional to determine whether or not they might salvage the insulation. They will also give you the appropriate recommendations.