filling space for spraying... | Ask Mason Knowles - SPF Consultant | Spray Foam Technical Questions and Answers | SprayFoam Magazine Q&A Forums

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armorfoam Posted: Jan 15, 2018 03:34 AM	filling space for spraying... Is there anything you would suggest to close small spaces so that you could spray foam. I have a 6 inche space above some rafters I need to foam and I need something for backing to install and foam.
mason Posted: Jan 15, 2018 01:40 PM	Use a stiff construction board that is easy to cut but will stay in place (closed cell insulation foam boards work well too). It doesn't have to fit perfectly. The rising foam will fill in the cracks.
Mister Posted: Jan 18, 2018 03:08 AM	armorfoam For eaves and cavity fills, typically a 1/2" foam board works great to easily cut with a utility knife, shape, and install as blocking for a foam application. Occasionally other products work. Many commodity contractors will try to just stuff it with fiberglass because it's easy and cheap. But then your foam applicator , spraying out of a gun at 1100 PSI, will blow the fiberglass away and then its a shitshow. We cut think rigid foam to fit, and then utilize our window and door foam gun to seal around it to lock it in. It works perfectly. However, it takes time to do this process so you need to charge for it.

Author

Comments

armorfoam

Posted: Jan 15, 2018 03:34 AM

filling space for spraying...

Is there anything you would suggest to close small spaces so that you could spray foam. I have a 6 inche space above some rafters I need to foam and I need something for backing to install and foam.

mason

Posted: Jan 15, 2018 01:40 PM

Use a stiff construction board that is easy to cut but will stay in place (closed cell insulation foam boards work well too). It doesn't have to fit perfectly. The rising foam will fill in the cracks.

Mister

Posted: Jan 18, 2018 03:08 AM

armorfoam

For eaves and cavity fills, typically a 1/2" foam board works great to easily cut with a utility knife, shape, and install as blocking for a foam application. Occasionally other products work. Many commodity contractors will try to just stuff it with fiberglass because it's easy and cheap. But then your foam applicator , spraying out of a gun at 1100 PSI, will blow the fiberglass away and then its a shitshow.

We cut think rigid foam to fit, and then utilize our window and door foam gun to seal around it to lock it in. It works perfectly. However, it takes time to do this process so you need to charge for it.

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