Does plasterboard provide any insulation?

Plasterboard is the most common modern creation for building walls. This modern use is no accident because it’s cheap and offers many advantages. Its gypsum base offers little insulation though.

Plasterboard does not provide any insulation. It has an R-value of about 0.5 meaning that it does not retain heat well. There are variants of plasterboard that have higher values and that are better insulators.

Using Plasterboard To Insulate

Plasterboard (also known as drywall) is basically crushed gypsum covered in paper. It alone provides little insulation because of this. It is a big help when compared to nothing, but offers little more protection than a wind barrier.

Nature likes to be balanced. So heat moves to cold areas to make this happen. Insulation’s job is to slow this down as much as possible. The usual plasterboard is about half an inch thick.

So by using just plasterboard to insulate, you will still slow the transfer down but hardly at all.

This means that you will need to heat the area greatly to negate the effects of heat loss. Or vice versa. Rock just simply does not hold heat very well. It’s considered more of a thermal mass.

It absorbs heat easily, then radiates it out when it gets cold. Think of it like a rechargeable battery that doesn’t get much of a charge anymore. Using drywall as an insulator is just no good.

Depending on the frame of the house and how it was constructed can change how good thermal mass plasterboard will act.

Overall, plain plasterboard is not very good at insulating a home. To really help insulate your home you will need to understand R-values, use proper insulation, and know how to improve the value.

Understanding R Values

R-values represent how good of an insulator something is.

R-values are described as heat flow rate. The larger the value, the more resistant it is to heat flow. It is also described as thermal resistance R-values are based on the thickness and the type of material in question. They are also affected by the climate and temperature. They increase when materials are placed together and decreased when removed.

R-values for a wall are calculated by simply adding up each individual r-value and totaling them. This will give a good idea of how well your wall insulates.

As a general rule of thumb, an energy-efficient home has walls with an r-value around 20.

Plasterboard has a low r-value for a couple of reasons. It is thin, not very dense, and collects heat without giving it off like a black hole. You should not use plasterboard by itself to insulate.

Why do R-values matter? Building codes. Buildings have to have an overall R-value that exceeds a certain requirement. If they do not, they will fail any home inspection and you will need to make the proper changes.

Variants Of Plasterboard

Plasterboard has several variants, each with differing properties. Most of them have similar insulating properties. These include:

  • Mold resistant
  • Sound resistant
  • Moisture resistant
  • Fire resistant
  • Insulated

These are all pretty self-explanatory. So we’re only going to talk about the last one.

Insulated plasterboard is most often just normal plasterboard with insulation glued to it. You can however find it mixed with the other types of plasterboard.

The insulation comes in varying types and thicknesses. So prices vary quite a bit. It is far more expensive than buying the plasterboard and insulation separately though.

Installation of these boards is pretty straightforward. All you do is screw them into the wall like regular plasterboard. You may need to remove parts of the insulation to get the plasterboard part to fit snuggly against the frame of the house.

Insulating Options

With these things in mind, there are plenty of better options for insulating your house. Plasterboard just simply isn’t a good option to keep you warm.

These options range from fiberglass to foam. Each with advantages and disadvantages that we will cover.

Fiberglass insulation has been around for 80 years. It is moisture-resistant and fire-resistant. Making it a great option for fast fixes. It is easy to install, but be careful because the fibers are prone to get on everything. Dress in long sleeves and cover your eyes.

It is also recyclable. About 50% of all fiberglass insulation is recycled into more fiberglass insulation.

The downsides are that it isn’t as good as other insulations. It also costs more to produce than other options. Though, with that said it is still the most common option because it’s easy to produce and handle.

To install the fiberglass, you hang it up between the outer wall and the inside plasterboard.

Foam comes in two options. Spray and board.

Boards have a very high R-value and are easy to install. They often come with Foil on one side for better insulation and are often water-resistant.

Spray eliminates a lot of other homeowner problems such as drafts and air leaks. It allows for another insulator to be installed. It is however very expensive.

Natural and Denim are recycled materials that provide a decent R-value. They are often not water-resistant though and require proper water shielding.

Mineral Wool has a higher R-value than fiberglass does, is much more recyclable, and is fire-resistant. It is far more expensive though and much heavier.

All of these however have to be held in place by plasterboard. They all go in between the walls of your house.

Final Thoughts

The original question, “Does plaster provide any insulation?” has the answer of no. It really doesn’t. Its rocky nature prevents it from protecting the heat it needs to. It does however provide a great barrier for real insulators.

Real insulators come in many varieties and require an individualized touch before you go out and start your project.

If you’re looking to cut corners when insulating a room or house, do not put up just drywall. It will cost you more in the end than just putting the insulation now when your walls are already torn apart.

So don’t plan on using plasterboard for insulation. It doesn’t do a good job at it.

Ricky Kesler

With all of the projects I've done over the years, you'd think that I work on my house full-time. But I actually enjoy other things like spending time outdoors and time with my family.

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