Will Spray Foam Insulation Keep Water Out Effectively? 

Spray foam insulation in new house loft

Water ingress and dampness is a severe problem that can compromise your house’s integrity. For this reason, you may consider reinforcing your home’s insulation to keep water from harming your home and installing spray foam.

But will spray foam keep water out of your home effectively? Let’s answer all your questions about spray foam insulation and wet issues below.

Spray Foam Insulation 101

Before you call a home insulation company, you should take the time to understand what spray foam insulation is and how it works.

What Is Spray Foam?

Spray foam insulation, also called polyurethane foam or SPF, is a liquid insulation that creates a foamy, cloud-like material inside walls, floors, and ceiling spaces. It’s a popular alternative to other insulation methods, such as slabs, rolls, and bats.

The spray foam acts as a seal in building cavities. It fills building gaps like electrical outlets, light fixtures, and the spot where walls meet doors or windows.

By sealing these unwanted gaps, the spray foam can make your home more energy efficient and save it from elements that can compromise structural integrity.

This method of insulation became popular in the UK from the 1970s onwards. People loved its energy-efficient properties, making it one of the most preferred insulation materials until today.

How Does a Spray Foam Insulation Work?

Spray foam is basically a spray-applied plastic that creates an air-tight seal around your home. It uses two types of composite materials: polyurethane and isocyanate.

When sprayed into a cavity, the chemicals react and expand, creating the foamy cement material. It fills the space upon contact, sealing the air and creating a barrier.

Is Spray Foam Insulation Water-Resistant?

Now comes the most vital question. Can spray foam prevent water from entering into your property and affecting your ceiling, walls, and other spaces?

To answer shortly: YES, spray foam can resist water from entering your home. The air-tight sealing it provides helps keep moisture from seeping inside and damaging your property.

Many use it successfully for sealing home spaces prone to leaking, including crawlspaces and basements. In doing so, they prevent water from seeping through the buildings’ foundations.

However, the spray foam’s water-repelling properties can depend on the spray foam type. Some spray foams are more effective than others when protecting your house from water.

It’s also important to remember that the purpose of spray foam isn’t for water-proofing. So, despite its efficacy in keeping leaks in check, most experts wouldn’t recommend using it for this particular purpose.

There are materials and methods designed specifically for waterproofing your home. So, if leaking and moisture are the primary issues you’re dealing with, it’s still best to rely on those.

Still, it doesn’t mean you can’t simultaneously insulate and seal your property from water. Spray foam does offer excellent insulation and moisture protection that can reinforce your property’s waterproofing.

Are All Spray Foams Water-Resistant?

As mentioned above, the water-sealing capability of spray foams can depend on their type. We currently have two varieties of spray foam sealing: open-cell and closed-cell.

Open-Cell Spray Foam Insulation

Open-cell SPF is a softer variety of insulation. We typically use this type of spray foam in building interiors, like walls, ceilings, and ducts.

The lower density is owed to the variation introduced while making the polyurethane. The reaction from this variation creates air pockets or pores in the material, hence its softer texture.

Because of its structure, open-cell spray foam isn’t that effective in keeping water at bay. It can offer some water protection to some degree, but you can’t use it in spaces with excessive water issues, such as a leaking basement.

Still, open-cell foam does offer some advantages. For example, it expands significantly more than closed-cell SPFs, making it the better choice for filling hard-to-reach crevices and spaces.

Closed-Cell Spray Foam Insulation

As you may have guessed, closed-cell SPFs are denser than open-cell foams. It’s more robust and doesn’t have large air pockets or pores.

Its almost solid property makes it better at resisting water coming from the outside. As such, closed-cell foam is the best pick if your goal is reinforcing your house’s waterproofing.

The tight construction of closed-cell foam is due to the blowing agent introduced to the chemical while making the polyurethane. The resulting foam is a rigid insulation material with two to three pounds per cubic foot density.

Closed-cell SPFs have higher compression resistance to low-density foams. It also provides better thermal insulation and increases the integrity of the structure.

Other Purposes of Spray Foams

Aside from its water-resisting capability, spray foam can perform the following functions:

Lowering Energy Cost

Spray foam is an insulating method known for its temperature-regulating capability. It means it’s effective at trapping heat or cold inside your home.

With spray foam installed, your house will lose less cool air in summer and less warm air during winter. Less air escaping translates to lower energy bills.

Preventing Mould Invasion

Mould is a grave issue for households because of its health implications. But did you know spray foam can help reduce, even prevent, moulds from invading your property?

As you already know, moulds thrive in damp, enclosed spaces. Filling these spaces with spray foam allows you to control humidity and moisture, preventing mould spores from propagating.

Reducing Carbon Footprint

If you love making extra efforts for the environment, you’ll be glad to know that spray foam helps cut your household’s carbon footprint.

Effective insulation, such as spray foam, does more than cut your bills. By reducing heat or cold loss, your home relies less on gas or electricity-powered air conditioning.

Soundproofing Home Spaces

Reducing carbon pollution is essential for everyone. But, did you ever want to reduce noise pollution inside your home?

Spray foam is effective at absorbing sounds and noise. Open-cell foams, in particular, are excellent sound-absorbent materials for their softer construction.

Reinforcing Structural Integrity

Because spray foam conforms, sticks, and hardens, it reinforces the strength and durability of your wall, floor, or ceiling.

Most importantly, this added structural muscle can last decades without needing replacement. That’s decades less mould, moisture, and cost problems for you!

Frequently Asked Questions (FAQS)

Are you still curious about spray foam insulation? Here are some frequently asked questions from other homeowners:

Does Spray Foam Hold Water?

No, spray foam doesn’t retain water. Closed-cell foam doesn’t absorb water, and open-cell foam dries no matter how damp it gets.

Can Water Get Through Closed-Cell Spray Foam?

Closed-cell foam is highly water-resistant compared to open-cell foam. So, unless flooded, closed-cell foam should remain impervious to water.

Are There Advantages to Spray Foam Insulation?

Unlike other insulation materials, spray foam doesn’t lose its shape. The material can easily last decades without compressing, sagging, or settling.

Final Thoughts

To sum it up, insulating your home with spray does help keep water off your property. While not a replacement for specialised waterproofing methods, its water-resistant property makes it a valuable tool against water damage from leaks, vapour, and moisture.

Moreover, with added benefits like energy efficiency, mould resistance, and added structural strength, spray foam offers practicality in solving your home issues.

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