Best Insulation for Shop Walls

Working from a shop that isn’t insulated can make things uncomfortable, especially during extreme weather changes. The temperatures may even damage products in your shop, especially if moisture is present. The best methods of insulating shop walls are using spray foam or mineral wool insulation. In this guide, we’ve got you covered with how to go about each of the insulation for your shop.

Let’s dive right in!

Spray Foam Insulation

Spray foam is made from mixing isocyanate and polyol resin. Depending on the manufacturer, the two chemicals may also be referred to as components A and B, but basically, it’s the same compounds. Component A and B are mixed on-site and therefore come in two separate cans.

If you’re looking at just regulating temperatures within your shop, then spray foam is your best bet. Differences in temperature on the outside and the inside lead to condensation problems on the walls. Spray foam helps to minimize condensation problems on the walls of your shop. Here is the process of installing it on the walls.

How to install Spray Foam on the Shop Walls

The first thing you need to do before you start insulating your shop is to wear protective gear because spray foam emits dangerous fumes. When you want to insulate your walls, first remove any existing insulation. If you had none, then this step doesn’t apply in your case.

The next step involves preparing your insulation area so that you don’t damage other items with the foam. For this step, use plastic papers to cover items in the shop. You can use tapes to cover electric sockets on the walls. In this step, you also need to cover the windows and doors’ frames so that they don’t get insulated in the process.

Pick your gun, nozzle, and have several tips with you just in case you need to change. Ideally, if you stop using the nozzle for several minutes, it clogs such that you cannot use it again. Remember, spray foam dries really fast, becoming rigid on the nozzle. Also, make sure to have some lube to apply on the gun’s tip when changing the tips.

Spraying on shop walls is quick and fast, and you can do it yourself without hiring a professional. Spray uniformly to your desired thickness on the walls moving from one to the next. Once the foam cures, scrape off the excess foam using a serrated blade knife. Finally, clean the shop and remove the plastics used to cover your items. Also, remember to remove the tapes on your wall sockets.

What is the R-value of Spray Foam?

Spray foam is either a closed cell or open cell, and each has a different R-value. R-value is used to measure the thermal resistance of any insulation. Spray foam has the highest thermal resistance compared to other forms of insulation.

Closed cell spray foam has an R-value of between 6.5– 7 per inch, while open cell spray foam has an R-value of 3.2 – 3.8. Closed cell foam has more thermal resistance and air sealing properties compared to the open cell foam. However, the closed cell spray foam is pricier than the open cell.

Drawbacks of Spray Foam Insulation

Spray foam insulation is the best if you want insulation that offers thermal resistance, air seal, noise reduction, and energy efficiency. However, there are some drawbacks associated with this form of insulation as detailed here.

  1. More expensive

Undoubtedly, spray foam is more expensive than other insulation types, such as fiberglass and mineral wool. However, using the insulation gives you better results, especially if you’re looking at regulating temperatures.

  1. Confusing on the amount of use

One thing about spray foam is that you really don’t know how much is too much. Installers tend to use more than they actually should, which leads to wastage. Using more than you need will make you spend more to buy the insulation. As a general rule of thumb, you should only use about 2 inches of closed cell spray foam on walls as anything beyond that is wastage.

  1. Doesn’t come off easily

Spray foam works perfectly when put in place, but if you decide you don’t want it anymore, it can be hard to remove. Spray foam isn’t the same as mineral wool or fiberglass batts that you can quickly remove when you don’t want insulation anymore. 

Mineral Wool Insulation for Shop Walls

The other alternative insulation for your shop walls is mineral wool, which is made of molten glass, industrial waste, and stone. The materials are taken through spinning, resulting in fibrous structures. Mineral wool is an excellent form of insulation if your shop is located in a noisy area near the road because it reduces noise.

The soundproofing capabilities of mineral wool are the best if you compare it with other forms of insulation. Placing the batts between the wall studs can prevent sounds from leaving the shop or noise from outside affecting your work.

How to Install Mineral Wool on the Shop Walls

Before you start using mineral wool insulation, make sure your walls don’t have any cavities on them. To seal the gaps on walls, you can use closed cell spray foam. Otherwise, air infiltration and moisture penetration will still take place. 

Mineral wool batts are easy to work with because they fit snugly on wall studs. You only need to have a serrated knife, which can help you cut the batts to precision. As you fit the batts in place, avoid placing double layers or compressing the fibers too much. By doing so, you prevent any interference with the quality of your insulation. Besides, if you have some wires and plumbing works, pressing down the fibers can interfere with their functionality.

When you start installing the mineral wool batts, the first step is to wear gloves, glasses, and a dust mask because the materials can make you itchy. The dust can also give you respiratory irritations. Using your bread knife, cut the batts according to the size of the interior walls studs. Fit the batts in the studs perfectly. Pay special attention to studs carrying some wires and other plumbing works. It would be best if you cut the batts to fit such places without interfering with the wiring.

Drawbacks to Mineral Wool Insulation

Mineral wool is great for noise reduction, prevention of moisture and air infiltration, and it’s also fire resistant. Mineral wool also keeps small insects and rodents away from your building. However, it has one main drawback.

Mineral wool is exceptionally hazardous, mostly when handled by non-professionals. The materials contain small particles that are highly itchy if they get into contact with the skin. Besides, the small particles, if inhaled, can cause severe respiratory complications. If you’ve never installed mineral wool before, it’s best to hire professionals.  

Air Sealing the Shop Walls 

If you’re going to insulate your shop walls with anything other than spray foam you will want to highly consider also getting them air sealed. Other types of insulation such as fiberglass and mineral wool lack air sealing properties thus creating the need to combine closed cell spray foam in the insulation. 

What is air sealing? 

A house that lacks an air seal allows in too much air, drafts, and dust through the cavities on the walls, roofing, or floors. Air sealing is the process of filling the gaps on the walls of your shop with an insulation that prevents air infiltration. Air sealed spaces are more energy efficient and comfortable for the occupants. 


Shops are at times located in busy cities or near roads where noise is rampant. Shops just like other buildings are also affected by extreme temperatures that can even lead to condensation on the walls. The best forms of insulation for shop walls is either spray foam or mineral wool insulation. Spray foam is the best if you’re looking at regulating the temperatures while mineral wool is ideal if you want to reduce noise.