Is foam board mold resistant?

Author: Wilburn Langworth  |  Last update: Wednesday, December 17, 2025

Expanded polystyrene foam boards are made with air bubbles that stop heat transfer. Unfortunately, those same air bubbles collect moisture which leads to mold and mildew growth. Solution: Rigid foam board insulation products are actually made to be water resistant.

Will mold grow on foam board?

Although its surface properties are not very conducive to the direct and rapid attachment of mold, if the environmental conditions continue to be unfavorable, mold may still find a foothold on polystyrene foam and gradually grow and spread.

What material is most mold resistant?

Options such as porcelain tile, vinyl plank, and engineered wood are highly recommended by Buffalo Restoration for their durability and resistance to moisture. These materials are easy to clean and maintain, making them ideal for areas susceptible to water exposure.

Is foam mold resistant?

As a product, spray foam insulation does not attract mold. And unlike wood or metal, spray foam does not rot, rust, or deteriorate. This means that an area properly sprayed with foam insulation will never become a food source or a hospitable environment for a mold colony.

What happens to foam board if it gets wet?

To answer your question, yes foam does lose its insulation value when it gets wet, but not 100% of it. And no, it will not dry out.

Mold-resistant Insulation with No Chemical Off-Gas

What are the negatives of foam board?

Cons of a Foamboard

Foamboards can get discolored, disintegrated or warped if left under the sun or rain. It can be used for a short outdoor event and not as a permanent outdoor display. Also keep it away from your bathroom or kitchen as steam can create moisture, affecting the foamboard.

Does foam get moldy when wet?

Open-cell spray foam is more porous than closed-cell foam, so it may absorb water if it gets wet. This can lead to decreased R-value and, over time, the potential development of mold or mildew if the moisture is not properly addressed.

Is foam board moisture-resistant?

A moisture-resistant and highly breathable insulation material, EPS brings critical performance qualities to the table. Its ability to dispel moisture can in turn, mitigate the risk of mold growth, ensure long-term thermal performance and support a comfortable, energy-efficient building envelope.

What is the best insulation to prevent mold?

Fiberglass insulation is constructed of tiny shards of glass that form pockets to trap air and help restrict the transfer of heat. Its naturally mold resistant in that the material itself is not a food source for mold.

Can mold grow on polyurethane foam?

The cell composition of spray foam prevents water or moisture penetration or absorption. Molds are not able to form. It's non-biodegradable, so it's not a food source for mold.

What material cannot grow mold?

While mold cannot get nutrients from inorganic material such as concrete, glass and metal, it can grow on the dirt present on these surfaces. Molds prefer damp or wet material. Some molds can get moisture from the air when the air is very damp, that is when the relative humidity is above 80%.

What does mold hate?

Mold hates light. Other than moisture there's nothing mold loves more than dark places. An easy prevention against mold growth is opening your blinds and shades. If it's warm enough out, open the windows.

Can a house be completely mold free?

It is impossible to get rid of all mold and mold spores indoors; some mold spores will be found floating through the air and in house dust. The mold spores will not grow if moisture is not present. Indoor mold growth can and should be prevented or controlled by controlling moisture indoors.

Does foam board need to be covered?

Left uncovered these boards' physical and insulative properties begin to weaken. First, their color fades, then the foam core suffers from powder chalking, and finally, the R-values deteriorate. To protect XPS foam boards from degradation, they must be covered within 60 days at the most.

What foam board can be left exposed?

ECOCELL Blankets can be left exposed or even painted. Unlike other insulation materials, ECOCELL does not have to be covered with gypsum board. Leaving ECOCELL exposed is another reason ECOCELL is the cost effective solution for insulating basements and crawlspaces.

Does styrofoam absorb mold?

Styrofoam is one of the most naturally mold-resistant forms of insulation, but in very extreme cases, it can still grow mold on its surface. This happens due to a combination of excessive moisture, along with an accumulation of organic material such as dirt.

Is foam insulation mold resistant?

While spray foam insulation offers excellent resistance to moisture and mold, it's not without potential issues. It's essential to apply the insulation correctly to prevent any problems like improper curing, which might contribute to moisture accumulation.

What can I put on my walls to prevent mold?

For this reason, we highly recommend Suretherm Anti-Condensation Paint. Suretherm helps prevent the route cause of the problem - the moisture! Suretherm Anti Condensation Paint is an internal water-based emulsion that is specifically designed to help deal with internal mould and damp caused by condensation.

Does a vapor barrier prevent mold?

1 – A Vapor Barrier Helps Prevent Mold.

What are the cons of foam board insulation?

Insulation Foam Boards Don't Work On Uneven Walls

This allows moisture to seep in. Excess moisture can cause mold, mildew, odors, decay, fungus growth and wood rot.

What happens when foam board insulation gets wet?

Moisture-saturated insulation not only loses its effectiveness but can also become a breeding ground for harmful microorganisms. The removal process should be executed meticulously to prevent any cross-contamination or health risks.

How long will foam board last outside?

The lifespan of PVC foam board can vary depending on the quality of the material and the environment it is exposed to. High-quality PVC foam board that is properly installed or maintained can last up to 20 years or more in construction applications and up to 5 years or more in outdoor signage applications.

What insulation doesn't mold?

Generally speaking, closed-cell insulation (i.e. cellular glass, phenolic, polyiso, and flexible elastomeric foam) is more resistant to mold spores than open-cell insulation (i.e. fiberglass).

Can bacteria live in foam?

Despite being ephemeral feeding grounds, foams are remarkably rich and diverse in microorganisms (Tsyban 1971), including bacteria (Gobalakrishnan et al.

What is the difference between mildew and mold?

Mildew has a gray, white or light brown color and generally rests flat on the surface of a moist area. It has a powdery appearance that may have a distinct, foul odor. Mold has a fuzzy, raised appearance and in unaired areas has a strong, musty smell. It often appears in darker shades of black, green and red.

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