What are the disadvantages of foam board?

Author: Emery Gutmann  |  Last update: Wednesday, January 28, 2026

Common polystyrene foam insulation board is easy to burn, and toxic smoke produced by combustion. Even adding a flame retardant, the combustion can only reach B grade. 3. Material strength is poor, prone to crack and insulation shedding phenomenon is relatively common.

What are the cons of foam boards?

Foam Board Insulation Problems
  • Decrease in insulating abilities. Overtime polyisocyanurate foam boards can decrease insulating capabilities. ...
  • Moisture collection. Expanded polystyrene foam boards are made with air bubbles that stop heat transfer. ...
  • Air leakage. ...
  • Improper installation.

What are the problems with foam board insulation?

While the foam board insulation can slow the movement of moisture through it, it is not completely impermeable, and moisture can still potentially penetrate the material over time. Additionally, any joints or seams in the insulation can create areas of vulnerability where moisture may be able to infiltrate.

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 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.

Spray Foam Insulation — The Ugly Truth?

How long does foam board last?

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.

How do I know if my foam board is waterlogged?

If you can feel a crack with your finger nail chances are water is seeping into the foam of the surfboard. These types of repairs can run $35 and up. Discoloration or Waterlogged: You will want to check the surfboard for signs of yellowed foam or brown spots.

Does foam board insulation need to be covered?

That said, it's still advisable to cover any foam board insulation exposed to the Sun within 30-60 days at the most.

How do you remove black mold from foam?

Mix baking soda with warm water for a cleaning solution. Use lemon juice. Mix equal parts of rubbing alcohol and water to remove the mold.

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).

What is the life expectancy of foam board insulation?

Foam board insulation, including types such as polystyrene, polyisocyanurate, and polyurethane, has a lifespan of 30 to 50 years. This type of insulation stands out for its moisture resistance and high thermal resistance, which contribute to its longevity and effectiveness in various applications.

What is the downside to foam insulation?

Spray foam insulation is a good insulator in terms of keeping a room warm or cool. But its many downsides outweigh the benefits. These include, making it more difficult getting a mortgage, potential health issues, environmental damage, ventilation issues and a lower home valuation.

Is foam board a fire hazard?

Rigid polyurethane and polyisocyanurate foams will, when ignited, burn rapidly and produce intense heat, dense smoke and gases which are irritating, flammable and/or toxic. As with other organic materials the most significant gas is usually carbon monoxide.

What is a cheaper alternative to foam board?

Mineral-filled polypropylene is one of the least expensive styrofoam alternative options. In fact, it is the least expensive sustainable alternative.

What's better insulation or foam board?

Making the Choice: Key Considerations. Climate: For colder or damper environments, foam board offers superior R-value and moisture resistance. Budget: Batt insulation is the go-to for cost-conscious projects.

Do I need house wrap if I use foam board?

House wrap helps prevent moisture damage, but when coupled with foam siding they create an unstoppable force. Moisture Management System for your home: It's estimated that each person uses 80-100 gallons of water per day at home. Instead of that moisture becoming trapped inside the home, foam can help it escape.

Can mold grow on foam?

Foam is ideal for offering natural air cushioning, insulation and sound absorption under flooring, but can be a prime spot for unseen fungal growth.

What are symptoms of black mold exposure?

The most common symptoms of black mold exposure include:
  • Sneezing.
  • Coughing.
  • Nasal congestion.
  • Postnasal drip.
  • Red eyes.

Does baking soda get rid of black mold?

For a natural solution to getting rid of black mold, combine one part baking soda with five parts distilled white vinegar and five parts water in a spray bottle.

When should I stop wearing foam boards?

FOAM/BOARDS: Add foam inside your compression garment within 24 hours of surgery (see video above) for any liposuction areas to create even compression. Recommend wearing a polyester layer directly over the skin first to prevent skin irritation. Foam is continued for 1 month post op minimum.

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.

Can you put drywall directly on foam board?

A: Myron Ferguson, a drywall contractor in Galway, N.Y., responds: These days, rigid foam is usually installed on the exterior, but back in the '80s I installed a lot of drywall directly over interior foam board — typically 1-inch foil-faced polyisocyanurate fastened right to the framing.

Does foam board trap moisture?

Some walls had leaky vapor barriers and some did not. The 2-year study reaffirmed the idea that foam can act as a “double vapor barrier” by trapping moisture in the walls.

How do you seal foam board?

Use foil tape or foam sealant to seal the edges of the foam board insulation, creating a tight seal that will prevent air leakage and improve the insulation's effectiveness.

Can you walk on foam board?

For use under slabs, in a variety of compressive strengths suitable for the lightest residential to the heaviest industrial floor loads, FOAMULAR® insulation is durable enough to be walked on while placing slab reinforcing and concrete.

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