Where not to put insulation?

Author: Prof. Derek Hill  |  Last update: Wednesday, December 10, 2025

Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.

Is it bad to be in a room with exposed insulation?

Yes, sleeping in a room with exposed insulation isn't ideal. It can release dust and fibers into the air, which might affect your health. Additionally, it can be less effective at insulating. It's best to cover or properly finish the insulation for safety and better performance. Hope this helps with your home setup!

What ruins insulation?

Moisture damage

This can occur due to leaks in the roof or foundation, inadequate ventilation, or high humidity levels inside a building. Moisture can cause the insulation material to become compressed and lose its effectiveness, leading to increased energy consumption and potential mold growth.

Where is the best place to store insulation?

Wherever possible, the contractor should store the insulation in a dry, protected area. All packages should be elevated above the ground or slab, preferably on a flat surface, to prevent contact with surface water accumulations.

Can you install insulation wrong?

Besides safety concerns, installation inexperience can result in insulation mistakes that can affect both the quality of your insulation and installation. Improper placement can leave gaps and cause energy loss, lessening the insulation's lifespan.

THIS is Why Your Heat Bill is So High

Where should you not put insulation?

Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.

Can you put too much insulation in a house?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

What is the downside of insulation?

Irritation to skin and respiratory system

Wall insulation solutions like Rockwool are made of ultra-fine fibres. While thermally efficient, they can cause skin and respiratory irritation.

Is it okay to put plywood over insulation in an attic?

Can I put plywood over insulation in the attic? Yes you can install plywood subflooring directly over the floor joists and insulation on your floor. You need to install rigid insulation boards on top of the attic flooring joists and then install plywood over the top.

What areas of the home should be insulated?

Insulate all exterior walls, including (3A) walls between living spaces and unheated garages, shed roofs, or storage areas; (3B) foundation walls above ground level; (3C) foundation walls in heated basements. 4. Apply insulation to floors above unconditioned spaces, such as vented crawl spaces and unheated garages.

What are the problems with home insulation?

Look for damp patches, mould growth, cold spots, increased bills, or condensation. These signs could signal potential insulation problems. It's important to ask for professional inspection and advice without delay.

Where should you not use spray foam?

Directly against electrical wiring or fixtures: Spray foam insulation should not be applied directly against electrical wiring, fixtures, or recessed lighting unless they are rated for contact with insulation. Contact with insulation can cause overheating and pose a fire hazard.

Does mold grow on insulation?

Just about every type of home insulation, from cellulose to fiberglass, will act like a sponge wherever there is moisture. Even a small amount of condensation or leakage can cause big problems with mold if you don't notice it in time.

What is the biggest problem with fiberglass insulation?

Air Leakage

Fiberglass insulation is less dense than other types of insulation and does not create an airtight seal, which means air can travel freely through the insulation. This is called air leakage and it's one of the most common sources of energy loss in a house.

Is it bad to sleep in a room with insulation?

It's not safe to sleep in your house right after spray foam insulation is installed. The insulation needs time to cure, which can take hours or days. This curing process means off-gassing and health risks might be present.

Is yellow or pink insulation better?

In general, the color of insulation doesn't equal better performance over another color. Whether it's pink, white, brown, or yellow—color doesn't influence dependability, reliability, or the products effectiveness.

Where should you not put insulation in the attic?

Also, when laying down additional insulation, work from the perimeter toward the attic opening. Never lay insulation over recessed light fixtures or soffit vents. Keep all insulation at least 3 inches away from recessed "can" lights, unless they are rated IC (Insulated Ceiling).

Can you put flooring on top of insulation?

Yes. Installing loft flooring over insulation is a great way to reduce heat loss, noise, and your carbon footprint, among various other benefits.

Is drywall or plywood better insulation?

When deciding on drywall vs plywood for insulation, plywood offers better thermal insulation. Thus, it is suitable for use in regions prone to harsh weather. A drywall is better at sound reduction rather than thermal insulation. Thus, you can use drywalls to reduce a room's sound.

Does insulation increase house value?

A well-insulated home can also significantly impact its resale value. When it comes to buying a house, potential buyers look for features that will save them money in the long run. And insulation is one such feature that can positively affect the overall value of a home.

What should you not do when installing insulation?

Leaving Too Many Gaps

One of the biggest problems DIY homeowners face is leaving too many gaps in their insulation. Gaps or insulation that isn't secured correctly can leave the building structure open to air and moisture leaks. Spray foam insulation is best for reaching into small cracks and any areas left open.

What is a disadvantage of fiberglass insulation?

Fiberglass batt insulation does have some drawbacks. They can be itchy and irritating to handle, and inhaling the fibers can cause respiratory problems. It's important to wear protective clothing and a mask when handling and installing fiberglass batts.

How many inches of insulation in an attic?

If you live in the Southern part of the U.S., the recommended insulation level is a minimum of R-38 or about 13-14 inches of insulation. If you live in the Northern part of the U.S., the recommended insulation level is a minimum of R-49 or about 16-18 inches of insulation.

Can your R-value be too high?

The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space. While you might think that too much insulation can't be bad, there are some significant consequences to consider.

Can too much insulation cause mold?

Many of us know what causes mould; when moisture is trapped in the rooms of you home. Sometimes, there is insufficient insulation in the walls, so mould grows. However, not many people realise that additional insulation isn't always the answer. In fact, too much insulation can be the secret cause of mould.

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