How to Insulate Between Your Floors: A Full Guide

insulation between floor

Believe it or not; your floors actually play a significant role in how comfortable you feel inside your house. Floors aren’t only there to hold your weight; they do have a say in how warm your house is and even how noisy it can get.

If the temperature in your house is unstable and disruptive noises are getting louder by the day, it may be the right time to consider insulating between your floors. An insulated floor will prevent heat loss, keeping your house warm in the winter, and it will minimise unwanted noises from the space below and serve as a moisture barrier.

Here’s everything you need to know about how to insulate between your floors, how important it is, and what materials to use.

Should You Insulate Between Floors?

If you’ve been living without insulation between your floors for this long without any real issues, why should you start considering it now?

Well, first, to answer your question, you absolutely should insulate between floors. Contrary to popular belief, it’s no less important than insulating the walls and ceiling of your house. It’s recommended to keep your floor insulated, especially for floors above crawl spaces and unheated garages.

The reasons are simple: insulating between floors accounts for a more comfortable house. It prevents heat loss between rooms divided by floors, resulting in lower heating bills in the long run. On top of that, it reduces noise and soundproofs your rooms.

What Type of Floor Do You Have?

Before you decide to insulate between your floors, you have to first identify the type of floor you have. It’d be easy to do so by going into the cellar or basement under your house. If the wooden joists are visible under the floorboards, then you have a suspended wooden floor.

Since not all people have access to the areas beneath their houses, you can try a different approach. If applicable, you can raise one corner of your carpeting or underlay and take a look below.

Generally, most houses nowadays either have solid concrete floors or suspended wooden floors. If your house is new, it’ll likely have a solid concrete floor. In this case, you can only insulate between floors when you need to replace them or at the time of construction. Alternatively, you can insulate your floor by installing rigid foam insulation on top of it.

On the other hand, if you have a suspended wooden floor, you can easily insulate it by removing the floorboards and installing the insulation materials between the joists. 

Insulation Between Floors: Advantages and Disadvantages

For some house owners, insulating between floors is necessary. For example, when a house has an unfinished attic space and slab floors built directly on the ground, it becomes essential to install insulation to seal the area underneath the house.

If your case is different and you’re still not sure whether to insulate between your floors, here’s a rundown of both advantages and disadvantages:

Advantages

  • Insulating between your floors helps stabilise the temperature in your rooms because it prevents heat loss and gain. Since heat typically travels from areas of high heat to areas of low heat, the rooms above your kitchen, for example, are prone to temperature irregularities. If you install insulation, the room above your kitchen won’t suffer from sharp temperature rises.
  • For the same reason as above, insulating your floors will keep your energy bills low. Preventing heat loss means that your cooling and heating devices will work more effectively because the temperatures will be stable. As a result, they’ll use less electricity to work, accounting for lower bills at the end of the month.
  • One of the most prominent benefits of floor insulation is noise reduction. Two-story houses are no strangers to background noise like footsteps, loud voices, and the whirring of electrical appliances. Insulating your floors will stop the sound transfer, soundproofing your rooms.
  • If you live in an area with icy weather, floor insulation prevents your pipes from freezing because it prevents airflow. That’s especially true for under-floor pipes.
  • Insulation between your floors serves as a moisture barrier, protecting the floors from water damage and mould growth, which are both common when moisture is plenty.

Disadvantages

  • If a water leak occurs, it could end up causing mould growth in your floor insulation. As a result, it’ll cause air drafts with an unpleasant smell, and it’ll serve as a health hazard for the people living in the house. Regular exposure to mould is dangerous and could lead to respiratory problems.
  • If your floors are subject to constant water exposure, the insulation could eventually get wet, which can be dangerous because it makes it heavier and more prone to growing mould and mildew. Plus, wet insulation has a life expectancy, and will eventually break or fall apart, so you’ll have to replace it. 
  • If you haven’t installed insulation between your floors during the construction phase, it’ll be a bit challenging to do it later on. It’ll consume time and require skills and patience, so it’s generally better to hand it off to a professional.

The Best Materials for Insulation Between Floors

Good insulation materials are known to be fibreglass, rigid foam, plus others, but which insulation type is suitable between floors? 

Here’s a rundown of the best materials for insulation between floors:

Spray Foam

Spray foam is one of the most popular insulation materials because of its convenience and ease of use. If you have enough DIY skills and know your way around floors, you can apply it yourself. You’d only have to wait until it expands and fills the space. 

Aside from its ease of use, spray foam is also moisture resistant and excellent for preventing air flow between walls or floors.

Because it’s easy to apply, spray foam is a popular insulation material for challenging areas, like crawl spaces, floor joists, and between floors. However, it’s not that common because it’s relatively more expensive than other materials.

Fibreglass

Like spray foam, fibreglass is one of the most popular insulation materials. Fibreglass batts and rolls are especially common in both residential structures and commercial structures because they’re fire-resistant, so they comply with building codes in most areas.

Batts and rolls are also known for their acoustic insulation, which is why they’re often used for soundproofing purposes.

Thankfully, fibreglass is generally easy to install and doesn’t require much expertise. It’s also the most cost-efficient insulation material for floors. However, it’s worth noting that fibreglass has a short lifespan because it’s prone to mould and mildew, and it may warp due to water damage and require replacement.

How to Insulate Between Floors

Before starting, you should know that insulating between floors isn’t a walk in the park. It’s an awkward place to insulate, so it requires some patience and skills. If you don’t regularly handle DIY projects around the house, it may be a good idea to leave it to a professional to do it for you (We can help with that!)

On the other hand, if you think you’ve got what it takes, here’s how to insulate between floors using batts:

  1. When the ceiling cavity is exposed, station yourself at the bottom and prepare your tools.
  2. The first thing you should do is seal all holes using an acoustic sealant, so you can achieve soundproofing. Make sure to cover all holes, including those for electrical wires.
  3. Start grabbing your batts and inserting them between the joists. The most important part of this step is making sure there are no gaps. Make sure that the batts are snugly fit to prevent unnecessary holes.
  4. Apply the plaster, then start returning everything to its place. If you want to make sure your insulation is ironclad, you can also install resilient channels before the plaster. It’ll reduce the number of vibrations passing through the floor, further reducing noise.

Should You Do the Insulation Yourself or Hire a Professional?

In most cases, it’s cheaper to do the work yourself than to hire a professional, but not all tasks are easy enough for this. Insulating between floors is an intricate job that requires basic knowledge of insulation. If you’re not a DIYer, it’ll probably take you some guesswork to do the job, and it won’t be smooth sailing.

Insulating between floors requires skirting boards, sealing gaps, and ensuring the floor is entirely dry. Not to mention, you’d have to cut the insulation material in accurate measurements and fit it correctly between the floorboards. 

If you don’t feel confident about doing that yourself, hiring a professional is the easy way out. The cost will depend on the size of your house and the type of floor. Naturally, it’s more costly to do so, but it’ll take your mind off the hassle of it, and you’ll make sure that the process is done safely by experts.

If you want to find the best insulation contractor in your area, we can help with that.

Final Thoughts

If you want to insulate between your floors, you must first identify the type of floor you have. Then, you’d have to choose the best insulation material and cut it according to the size of your floorboards. After that comes the hard part, which is installing the insulation. 

If the process seems too much for you, it doesn’t hurt to ask for a professional opinion and explore your options. Doing it yourself is cheaper, but you don’t want to risk doing it incorrectly for the sake of saving money.

Frequently Asked Questions

Should you insulate floor joists?

It’s not necessary to insulate floor joists, but it’s generally recommended, especially if you have unconditioned areas beneath the floor, like a crawl space, an unfinished basement, or an unheated garage.

In this case, it’s better to insulate floor joists to minimise airflow and maintain the temperatures inside your house. Insulation prevents cracks and gaps, which, in turn, prevents air drafts from passing from one level to another.

Does insulation between floors prevent heat loss?

Yes, insulation between floors prevents heat loss because it covers all cracks and gaps, which usually lets air through. Excessive air flow inside your house can cause irregular temperatures, which cause your cooling and heating appliances to work overtime.

Should I insulate the floor above my garage?

If the rooms above your garage are high-traffic or main, like a living room or a bedroom, you should insulate the floor between them. A garage is generally an unconditioned area, especially if it’s not insulated itself. It’s a source of noise from cars, maintenance, etc.

Insulating the floor will keep the noise and heat from reaching the rooms above.

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