After applying spray foam insulation, you might want to screw into it to hang a picture or mirror or to secure drywall to the studs. But is it really that easy? Can you just grab a screw and start twisting away?
Spray foam hardens significantly once it cures. So, screwing a few days after the application is usually fine. But if you wait too long, the foam will be too hard to penetrate without first drilling a pilot hole.
Here’s a detailed overview of this.
Can You Screw Into Spray Foam?
Technically, yes. You can screw into spray foam insulation after it has cured. However, there are a few things you should know before doing so.
First, it is important to understand that spray foam expands. When it is first applied, it is in a liquid form. But as it dries, it expands and hardens.
The expansion is what helps to seal cracks and gaps in your home. But it also means that you need to be careful when screwing into the foam.
The foam will be too hard to penetrate if you wait too long. In that case, you’ll have to drill a pilot hole first. Also, closed-cell foam is more rigid than open-cell foam, so it will be harder to penetrate.
How Long To Wait Before Screwing Into Spray Foam?
Ideally, you should wait 24 hours before screwing into spray foam. This gives the foam time to expand and harden.
However, if you can’t wait that long, you can usually get away with screwing into the foam a few hours after it has been applied. Just be careful not to apply too much pressure, or you might damage the foam.
If you take this approach, the foam will harden around the screw. Do note that removing this screw will be a pain later.
What Screws Will Hold Into/Work Well With Spray Foam?
You can use any type of screw, but we recommend using screws specifically designed for foam board. These have a sharp point that helps penetrate the foam.
You can find these screws at most hardware stores. Just make sure to get the right size for the thickness of your foam board.
Some examples of these screws are:
- Foam Board Screws
- Tapcon Concrete Screws
- Deck Screws
Can Spray Foam Support Weight?
Yes, spray foam can support weight since it’s high-density insulation with significant structural integrity. Per square inch of spray foam can hold around 50 pounds of weight.
Closed-cell spray foam is better at supporting weight than open-cell foam. That’s because it’s denser than open-cell foam and has a higher R-value.
Moreover, the density of spray foam determines how much weight it can support. The rule of thumb is that the denser the foam, the more weight it can hold.
Just remember that the foam will compress and expand depending on the temperature. So, if you’re hanging something heavy from the foam, ensure it’s not in an area that gets too hot or cold.
Otherwise, the foam might expand or contract too much and cause the object to fall.
