If you are planning on installing some drywall to make your walls look nice, but you have concrete walls and floors, then there are some important things to be aware of. You might be tempted to put that drywall right on the concrete, but is this really a good idea? Can these two materials touch or should there be a gap?
Let’s figure out how to properly install that drywall over concrete.
Can Drywall Touch Concrete?
Although you can install drywall over concrete, you should be mindful of the fact that they should not directly touch. If you have concrete floors and are looking to hang drywall, there should be some kind of layer in between the concrete floor and the drywall being hung vertically.
If you have concrete walls and are looking to hang drywall overtop, you do need to have a material barrier between the two, which could be a number of things, as we will discuss further below. However, the bottom line here is that no, drywall should never be in direct contact with concrete, because you may run into problems.
How Large of a Gap Should There Be Between Drywall and Concrete?
As we have established, there should be no direct contact between the drywall and the concrete, which means that you do need to leave a bit of a gap. Now, exactly how large this gap is will depend on exactly how you will be creating it.
Generally speaking, you want to leave between 1/2” and 5/8” of a gap between the concrete and the drywall, as this will help save you from many different problems later on down the road.
Sure, creating that gap is going to take a bit of extra work during the installation process, but this slightly more difficult installation is going to lead to benefits in the long run, particularly when it comes to that drywall staying in one piece.
That said, how are you going to create this gap, and what kind of material should be used to fill it?
What Should You Put Between Drywall and Concrete?
Ok, so if you can’t put drywall directly onto concrete, then what should you use to create that gap, and what should be inside of that gap, if anything at all? Let’s take a quick look at all of the different options at your disposal here.
Studs and Insulation
If you are hanging drywall, then one of the easiest ways to go about it is to attach studs to the wall. Now, this method is usually something that you would use for houses that have wooden frames. However, if you have a concrete house, you can always install a wooden frame using regular boards.
Create a frame that is of the ideal size for attaching drywall. Then, to prevent moisture and air from leaking through, using foam insulation combined with a plastic vapor barrier should do the trick. This way, your drywall stays off the concrete and you end up insulating your house at the same time.
Foam or Kerdi Board
Another method at your disposal here, something that you would usually do when installing tiles in high-traffic and high-moisture areas, although also works as a drywall underlayment, is using foam boards or specialized Kerdi boards as a moisture barrier.
Here, you would use Thinset to attach the board to the concrete, and then use specialized mounting hardware to attach the drywall to the foam board. These foam or Kerdi boards are specially designed to prevent moisture and air from leaking through, and they also provide you with a surface that you can easily attach the drywall to.
Plywood
Another option here is to put a layer of plywood in between the concrete and the drywall. Plywood will help to absorb and control moisture, thus preventing it from getting to the drywall. This material is relatively easy to install over concrete, and drywall is easy to install onto plywood.
However, do keep in mind that both drywall and plywood are relatively heavy, so you’ll definitely need a helping hand. Moreover, although this is a good option to consider, you should still think about using a moisture or vapor barrier for some added protection.
Moisture Barrier
No matter the case, you should always use a moisture or vapor barrier, which is more or less just a sheet of plastic. This plastic is airtight and waterproof, so it will stop moisture from getting to the drywall.
3 Problems You Could Face If Your Drywall Touches Concrete
There are three specific issues that you will usually face if you try to install drywall directly onto concrete, and not only will they make life harder, but more expensive as well.
Moisture Issues
The biggest issue you will be faced with if you put drywall right onto concrete is that moisture will slowly seep in. That drywall is going to absorb any and all moisture that is present on that concrete, whether it was already there or if it gets in due to imperfections. Your drywall is going to start to crumble into pieces, and mold may even start to form. If your drywall gets crumbly and moldy, then you have some serious issues.
Installation Issues
Another thing to consider here is that concrete floors are rarely totally level and even. This means that installing drywall right overtop of concrete can be very difficult, almost impossible, especially if you want the drywall to be straight, level, and plumb. The worst case here is that you actually snap the drywall when trying to form it to an uneven concrete surface.
Movement Issues
The other issue here is that drywall and concrete expand and contract at different rates depending on the temperature. This means that when temperatures change, the two materials may put pressure on each other, and because drywall is much weaker than concrete, it’s the drywall that will start bending, crumbling, and breaking.
Summary
As you can see, there are many ways to create a good gap between concrete and drywall, and yes, you do need to choose one of them, as drywall should never directly touch concrete.