Using spray foam insulation is a tried-and-true approach to insulating a newly constructed home or other building, since the material can be inserted between studs in wall cavities and easily covered over with drywall and other finishing materials. But what about existing structures – can they benefit from this approach as well and reap all the same benefits?
So check out this handy guide from the team at team at SprayWorks Equipment to learn everything you need to know when tackling this kind of project for a homeowner or business.
Your Guide to Applying Spray Foam in Existing Walls
As most contractors are aware, spray foam is an ideal material for insulation — its liquid form can be easily sprayed into a space, where it will expand, fill air pockets, and harden, creating an effective barrier from the elements.
New constructions often utilize the material as part of the project, but older homes and businesses might have other forms of insulation present, or simply none at all. So what’s the approach in that case? Let’s review.
The process at a glance:
| Step | What you’ll do |
|---|---|
| 1 | Check for old insulation |
| 2 | Assess how much spray foam you’ll need |
| 3 | Drill holes in the existing wall |
| 4 | Spray the foam into the holes |
1. Check for Old Insulation
Old insulation in buildings can be “sprayed over” with spray foam in the method we’ll describe below, as the new foam will simply fill in any gaps present between the current insulation and the wall cavity.
However, buildings with old insulation actually make the process a little more complicated than those with none at all.
- Moldy or damp insulation must be thoroughly removed before applying spray foam in the existing wall.
- Fiberglass insulation poses a problem when combined with spray foam, as the materials do not adhere well to each other and air pockets and moisture may form over time.
In these cases, some sections of the wall may need to be cut open to access the existing insulation for removal. Should no mold or dampness be present, and no fiberglass, then contractors can follow the steps outlined below.
2. Assess the Amount of Spray Foam You Will Need
Whether insulation is already present or the cavity is completely empty, you will need to determine how much spray foam material will be required for each segment of the job.
You will do this by measuring the square footage of your space and determining the R-value of your spray foam material, as well as that of any current insulation. An ideal R-value for a project of this kind would be R-38 at a depth of approximately 12 inches. Calculators are available online to help you in determining values.
One thing to note is that R-value differs depending on the type of spray foam you are using, namely closed-cell foam or open-cell foam.
| Spray Foam Type | R-Value per Inch |
|---|---|
| Closed-cell foam | 6.5 – 7 |
| Open-cell foam | 3.5 – 3.6 |
3. Drill Holes in the Existing Wall
Once your material needs are determined, you will then have to drill a few small holes (1 inch or less in diameter) in any walls the spray foam will be occupying. These holes will be used to insert your spray foam applicator’s nozzle so you can easily install the spray foam in the existing walls.
After the spray foam process is complete, these holes can be patched — returning the wall to its previous appearance and avoiding the costs and hassle associated with wall removal and reconstruction.
4. Spray the Foam into the Holes
Using your applicator nozzle, apply your spray foam insulation within the existing wall, directly into the wall cavity. As it is sprayed, the foam will expand and fill all spaces within the wall, and then harden — creating effective insulation.
Once you have completed the process for one wall cavity, you can move on to the next and repeat the process until finished.
FAQs About Applying Spray Foam Insulation in Existing Walls
What are some of the benefits of using spray foam insulation?
Since spray foam insulation creates such an effective seal within walls and other spaces, it supplies a variety of advantages, such as:
- Better energy efficiency and lower energy costs
- Reduced airflow throughout walls and from wall outlets
- Decreased noise pollution entering the building
- Greater comfort during colder and warmer months
- Greater temperature control
- Protection against moisture
Do occupants need to temporarily stay out of a building that has had spray foam applied in existing walls?
Homeowners are encouraged to vacate temporarily, while businesses may wish to close down operations for a short time, schedule the job for a weekend, or — depending on their size — close off certain areas to employees or customers.
Does spray foam need to be installed by a professional or can homeowners and businesses take a DIY approach?
Need Help Applying Spray Foam in Existing Walls? We’ve Got You Covered!
SprayWorks Equipment is comprised of a team of industry experts ready to assist you on your project. We can provide diverse options when it comes to materials, spray rigs, and other forms of equipment, as well as service and repair work and spray foam application training.
Contact our team today to inquire about any of our services so that you can successfully complete your next project. We’re ready to help!
