Do I Need to Remove Old Insulation Before Installing Spray Foam?

Upgrading your property’s insulation is like giving it a fresh start! And one of the most effective ways you can do that is by applying spray foam on your property’s roof. This way, it’ll seal all the gaps on the roof, keep your home comfy, and also reduce your energy bills. 

And if you agree with us, you’re probably already searching online for “the best spray foam company near me.” But before you do that, there’s one thing you need to know – 

“Should your old insulation stay, or is it time to clear that out first?”

Well, the answer isn’t always the same for every property and depends on the type and condition of your current insulation. And if you want to figure out what’ll work best for your property, you can give this blog a read!

How Spray Foam Works to Provide Better Insulation?

First, you need to understand how spray foam works, so you can take the right step to ensure your property’s insulation. 

Installing spray foam is an effective and long-lasting solution for improving your property’s insulation compared to traditional roofing solutions. It is a liquid solution made of two components: isocyanate and polyol resin. 

And when you apply Spray Polyurethane foam (SPF) or spray foam onto the roof directly, it slowly expands and forms a hard layer on the surface, sealing all the existing gaps and leaks on the roof. It’ll create a perfect airtight barrier and would prevent energy loss efficiently! 

That’s how it’ll keep your property cooler and comfortable in the summer and warmer and cozier in the winter without putting too much strain on the heating and cooling system. So, your energy bills will also be lower! Plus, proper insulation of the roof means you won’t face problems, like –

• Air leaks
• Excess moisture, causing mold and mildew
• Pest entry
• Damaged roof structure, etc.

But spray foam can work properly only when it’s installed the right way. That’s why the knowledge of whether to remove the old insulation or not before applying it is important! And that’s what we’ll talk about next!

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When You Should Remove Old Insulation

When your old insulation is compromised and damaged in any way, it’s always a better option to remove it entirely and then apply spray foam on the roof. If you’re unsure about the decision, you can look for the damages we’ve mentioned here to make the right choice for your property.

• Water Damage

If leaks have soaked your current insulation, mold can grow on it and block spray foam from sticking properly. To prevent this, you need to get rid of the old insulation before applying spray foam on the roof.

• Pest Infestations

Rodents and insects can damage insulation, leaving behind droppings or debris. So, you’ll have to remove the old insulation first, as you should always avoid applying spray foam on contaminated materials.

• Damaged or Friable Material

If your insulation is falling apart or releasing particles, it’s better to remove it to have a clean, smooth surface after applying spray foam on the roof.

• Compressed or Flattened Insulation

Over time, insulation can settle and form a flat layer. Spray foam needs room to expand fully, and old, flat, and worn-out insulation can stop it from creating a proper seal. So, in this case, you’ll have to remove the old layer first!

• Mixed Insulation Types

Layers of different materials (like fiberglass and cellulose) can interfere with spray foam’s expansion. If your roof has different types of insulation materials, you need to remove the old layers to ensure the spray foam can cover the entire surface properly.

• Chemical Contamination

If the old insulation has absorbed chemicals or harsh cleaners, spray foam may react poorly. So, clear it out first.

If you still have doubts about your decision, you can call an experienced roofing company for help. They’ll give you the right professional advice for your property and install spray foam efficiently so it performs at its best.

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When You Don’t Have to Remove Your Old Insulation

In some cases, your old insulation won’t interfere with the spray foam on the roof!

So, here’s when your professional spray foam installer can safely spray foam right over your old insulation – 

• It’s clean and dry: Fiberglass or cellulose that’s in good shape usually won’t interfere with the new spray foam layer.
• You’re sealing small gaps: For spot projects or areas where insulation is still effective, spray foam can work with the existing layer without you having to remove it.
• It’s not overly thick: Too much thickness of the existing insulation layer can prevent spray foam from expanding properly. A spray foam installer can check the area and adjust how much foam they use to make sure the new layer is applied properly over the old one.
• Good structural support: If the underlying surface is strong enough to handle the added weight of spray foam without causing any damage, then it’s safe to apply spray foam on the existing layer.
• Proper ventilation: If the area already has enough airflow or moisture control, keeping the old insulation may help improve the total R-value (which measures how well a material can resist heat) without trapping moisture.

Plus, you also need to make sure there’s no sign of pests, mold, mildew, or water leaks on the existing insulation before applying spray foam on it.

Removing Old Insulation vs. Spraying Over It – Which Option is Best for You? 

Here’s what you need to consider before making the decision! 

Feature	Removing Old Insulation First	Spray Foam Over Existing Insulation
Cost	More upfront cost for removing and disposing of the old layer	Lower upfront cost, as no removal process is needed
Installation Time	Longer (extra step of removal)	Faster
Energy Efficiency	More efficient because of a perfect seal	Good efficiency if old insulation is clean & dry
Moisture Control	Best, as there’ll be less chance of a wet or moldy spot	Good, only if the existing layer is dry
Durability	Lasts longer	Can last longer (but it depends on the condition of the old layer)

Quick Answers to Your Questions on Spray Foam Roofing

• Which spray foam type works better over old insulation?

Closed-cell spray foam generally works better over old insulation because it’s denser and creates a stronger air and moisture barrier, and attaches more firmly to existing surfaces than open-cell foam.

• Can you apply spray foam on top of shingles?

Usually, no! For applying spray foam, you’ll need a proper base surface that does not have any loose shingles.

• Will spraying over old insulation make my attic too hot?

No! It regulates temperature better, but you can still check the ventilation system regularly.

Takeaway

When you install spray foam on the roof, you’re creating an insulated, energy-efficient, and comfortable space inside your property all year-round! 

And if you already have a layer of insulation, a professional spray foam installer will check if it’s dry, clean, strong, and in good condition before applying spray foam on it. Or else, they’ll remove the old layer completely to ensure better performance of the spray foam roofing!

Read More About:

• Questions to Ask a Roofer Before Hiring
• Why Spray Foam Roofing Is the Best Roofing System
• Step-by-Step: How to Find and Fix a Roof Leak
• How to Fix Roof Leak Around Chimney?

Trust Foam Experts Co. for Your Spray Foam Roofing Needs!

For over 40 years, Foam Experts Co. has been providing reliable spray foam roofing service in Redding. We know how to do the job quickly, efficiently, and in an affordable way. Plus, we have licensed and bonded experts who can provide expert roof repair services with professional care. 

Our roofing company in Redding is the best you can find in town! So, if you want to protect your property’s roof, add spray foam on an existing insulated layer or start fresh after removal, you can rely on our excellent service at all times! 

Call us now at (530) 275-4588.