Insulating a home makes it cooler in the summer, and warmer in the winter, both of which reduce the cost to heat and cool a home. It also has the added benefit of making a home quieter and more comfortable. Drywall is one of the most common wall materials, and in this article I will explain if you can drywall over insulation such as spray foam, rigid foam, foam board, and blanket insulation (batts).
Overall, you can put drywall over spray foam, foam board, and blanket (batts) insulation. If the studs are not accessible, then you need to install furring strips to have a place to attach the drywall. A vapor barrier may also be needed but depends on a range of factors explained below.
For a regular wall where the studs are visible it’s very straightforward to install drywall over insulation. However, if you have a concrete or block wall you will need to install furring strips first.
Below, I will explain if it’s a good idea to put drywall over insulation and if there are any drawbacks to doing so, what tools you will need to do it, and finally by step by step instructions for exactly how to put drywall over insulation.
Should You Put Drywall over Spray Foam/Foam Board/Insulation?
There are a few different types of materials that can be used for walls, although drywall is the most common, there are a few other options such as plywood. Here’s a rundown of whether there are any issues with installing drywall over insulation, as well as, if it’s a good idea.
Overall, you should put drywall over spray foam, foam board, and other types of insulation. It’s a common practice in the building industry. The main consideration is having a place to attach the drywall. You may need to install furring strips, if the studs are not visible.
Concrete and block walls are reasonably common. However, insulation has a recommended thickness depending on the climate where you live to make it effective. This means it’s not possible to attach the drywall to the concrete or block underneath.
Therefore, a frame made out of furring strips needs to be installed before installing the insulation. The other consideration is if you will need to put a vapor barrier over the insulation. This is a sheet of plastic that stops moisture getting into the insulation which can cause mold.
Whether or not you need a vapor barrier depends on a few factors. This is explained at the very end of this article with the step by step instructions for how to put drywall over insulation. Refer to step 3 which is ‘install a vapor barrier’.
What Tools Do You Need to Put Drywall over Spray Foam/Foam Board/Insulation?
Installing drywall over insulation is simple to do, but it does require a few tools. Most of the tools you need you likely will already have but here’s a full list and what each of them are used for.
In general, you need a power drill, drywall saw – also called a keyhole saw, tape measure, pencil, straight edge, utility knife, ladder, putty knife, and carpenters level. These are used to measure and cut the drywall, to attach it to the studs or furring strips, and to finish the drywall.
Below, is a table that shows what each tool is used for:
What it’s used for
Attaching the drywall panels to the studs or furring strips
Drywall saw – also called a keyhole saw
Making interior cuts in the drywall to fit it around fixtures
Measuring out drywall cuts, and the dimensions of the wall or ceiling
Marking out measurements
Marking out cuts on drywall panels
Scoring the drywall to cut it to measure
Installing drywall panels on ceilings, and attaching the top drywall panels on a wall.
Filling in dents in the drywall panels using spackle made by drywall screws
To be aware of any imperfections in the dimensions of a wall or ceiling
If the underlying surface is a block or ceiling and you need to install furring strips, then you will also need a masonry drill bit to drill into the block or ceiling.
What Preparations Do You Need to Put Drywall over Spray Foam/Foam Board/Insulation?
Before attaching your first drywall panel there can be a few preparation steps. While not always required here’s a full rundown of all the steps that can be required before putting drywall over insulation.
In general, install furring strips into the underlying surface if you are installing drywall over block or concrete. Next install a vapor barrier over the insulation – only required in certain cases such as in humid regions, certain wall locations, and particular cladding types.
Whether or not you need to install a vapor barrier, or if it’s recommended is dependent on your climate, where the wall is located in your home, such as in a basement, and what type of cladding your home has. I explain how to know if you need to install a vapor barrier at the end of this article where it has the step by step instructions. Refer to step 3, which is to install the vapor barrier.
How to Put Drywall over Spray Foam/Foam Board/Insulation
Putting drywall over insulation virtually identical to putting drywall over an uninsulated wall or ceiling. While it’s fairly straightforward, there are guidelines and ways of doing it that you should be aware of. Also, if you have never hung drywall before, or haven’t done so in a long time below are full step by step instructions.
Overall, first install furring strips if the studs are not accessible, then install the foam insulation, and a vapor barrier. A vapor barrier is not always required. Next measure the wall to plan out the best orientation for your drywall panels, then do the steps below.
Copyright protected content owner: ReadyToDIY.com and was initially posted on February 13, 2023.
Cut the drywall panels to measure based on the plan you’ve made. If you are hanging drywall on the ceiling, start with the ceiling first, then do the walls. Here’s each step explained in detail:
1. Installing furring strips if the studs are not accessible
Drywall should ideally be attached to the studs. However, in some cases you may want to install insulation over concrete or a block wall. In that case you will need to install furring strips that are thick enough that you can fit the insulation you are using in between.
Furring strips are also required to have a place to attach the drywall to using your drywall screws. Drywall needs to be attached to the wall every 16 inches (40.6 cm) laterally. Therefore, the furring strips should be a minimum of 16 inches apart.
There are various very good videos available on Youtube that show how to attach furring strips to a wall. The main consideration is the furring strips need to stick out enough to accommodate the drywall screws. The drywall screws need to be a particular thickness.
To calculate this use the following calculation:
Length of drywall screws = (Thickness of drywall) + (Thickness of drywall * 1.5 )
Use this to know how far the furring strips should stick out from the wall.
2. Install the foam insulation if it hasn’t already been installed
Next install the foam insulation. Refer to the instructions on the insulation packaging or on the manufacturers website.
3. Install the vapor barrier
A vapor barrier is required in some cases. This goes over the insulation and stops as much moisture from getting onto the insulation, which can promote mold growth.
Refer to this article from CertainTeed, which shows a map of the USA, and shows if you need to install a vapor barrier or not. Also, it’s best to contact your State building codes office and ask them what the building codes are for your jurisdiction when installing drywall over insulation.
Copyright article owner is ReadyToDiy.com for this article. This post was first published on February 13, 2023.
4. Measure out the wall and plan out the orientation of the drywall panels
Drywall panels should be installed in a way that it minimizes the number of joins. Drywall panels can be oriented either longways or lengthways. The dimensions of your wall or ceiling will determine how to layout the drywall panels to have the least number of joins possible.
Also, above door frames and window frames, a join should not be at the corners of a door frame or window frame. If it is, the drywall will be more susceptible to cracking.
In addition, you should attach drywall to the ceiling before the wall. Doing so will hide the joins when you look up at the corners of the ceiling from below.
5. Cut the drywall panels to fit as you need them
Next cut your first drywall panel using a utility knife. To cut them only cut deep enough to cut the paper, then snap off the free end on a table or bench.
The underside will still be attached with paper. Once you’ve snapped it, cut it free by cutting the paper on the underside.
6. Attach them to the wall using drywall screws
Next attach the panel to the wall using drywall screws. Screw them in place one panel at a time. Below, is a very good video that shows an overview and instructions for each step in the process.
ReadyToDIY is the owner of this article. This post was published on February 13, 2023.