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How-To Guide

The Best Way to Seal around an Electrical Box!


Not sure how to use your Box Shell? This step-by-step photo guide will show you why the BOX SHELL is the perfect solution for insulating junction boxes. You'll be on your way to insulation perfection in no time.

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If you would prefer a video tutorial, check out our Videos page.


1. Make sure ALL electrical power is OFF.

2. Make sure the junction box has been properly installed and "rough-wired".

3. Fold/tear the BOX SHELL to fit the desired wall type. (This particular example is a 2x6 wall.)

4. Install the BOX SHELL over the junction box, making sure the wires are running through the wire cuts in the BOX SHELL.

5. Tape closed any gaps that may have been created in the installation process.

6. Staple or screw the tabs to the wall framing.

7. Install (fiberglass) wall insulation around the BOX SHELL. Install vapor barrier if desired.

8. Install wall board/finished wall material in the typical method. Paint if desired.

9. Install outlet/switch/trim device, but DON’T screw it to the junction box. Be sure the junction box can be seen.

10. Using low expansion latex spray foam, push the nozzle tube between the junction box and the BOX SHELL. Push tube all the way to the back along the box. Slowly fill up the void between the junction box and the BOX SHELL with foam. Look inside the junction box during this process. When foam starts to come through the wire holes in the back of the box, pull the spray tube almost all the way out. Continue to fill slowly until a small amount of foam can be seen all the way around the wall material and the junction box. NO foam will be seen on the framing side of the junction box.

11. Your junction box is now sealed! Wait and review foam expansion after 1 (one) hour. Clean up with soap and water as necessary.

12. Screw device into junction box. Wait for foam to completely cure, and make sure there is no foam inside the junction box before turning on the power.

You have now successfully installed your BOX SHELL!

You have insulated the void behind and around the junction box; you have a seal completely surrounding the wires; and you have completely sealed around the hole in the drywall.