BASEMENT AND CRAWLSPACE PROJECT GUIDE

DETERMINE YOUR GOALS

The first step in any successful project is making sure you know what you are setting out to accomplish. If you are looking to finish a basement into a living space, we’d recommend 2” of closed-cell foam. If you are simply air sealing and stopping moisture in a damp or musty crawlspace or basement, then 1” will do the trick. Rim joist bays, or the areas where the house sits on top of the foundation, are notorious for air leakage making them prime targets for the draft-stopping power of closed cell spray foam. They should be included in your plans whether finishing the space or just buttoning it up.

DO THE MATH

Your total required number of spray foam kits is determined by your total board feet need. A board-foot is one squared foot at one inch thick. Measure the length and height of your walls, and multiply those two numbers to determine the surface area square footage. From there, multiply that number by the number of inches thick you would like to spray, which will give you your total board feet. If finishing a basement, you do not have to fill the entire wall cavity full depth with foam; 2” will give you a tight air seal, stop moisture and deliver high R value. If you like, you can install batt insulation over the top of the foam before closing up the wall with drywall or similar. Divide your total board-feet need by 600 (the board-feet a Foam it Green 602 kit can cover), round it up to the next whole kit, and place your order!

PREPARE FOR SUCCESS

It’s difficult if not impossible to get foam off of surfaces it hits. So, be sure to take the time to cover anything you do not want foam stuck to including floors, windows, equipment in the area, and even you once you start spraying! Along with the recommended PPE, the sprayer should have no exposed skin or hair during application. How do you get foam out of a beard? In a word, scissors. Overspray can land many feet away from a wall you are spraying, and mistakes happen, like stepping on the gun or pulling off a hose, so cover everything! We do offer additional nozzles for purchase, as they will clog if you stop the flow of foam for 30 seconds. As always, make sure your target spray surfaces measure between 65F- 85F.

TECHNIQUE TIPS

Target a wet foam application thickness of 1/3” as that will expand to one inch cured. When spraying overhead, it’s recommended to leave off the fan spray tip and simply use the mixing nozzle alone. Get your hand a bit closer when pointing up, and use a lighter trigger pull so you don’t “bounce” the foam off the surface.

SPECIAL NOTES ABOUT BASEMENTS AND CRAWLSPACES

Setting your basement wall studs a bit away from the foundation will allow the foam to provide a thermal break between the cold foundation and the wall itself. So, it’s usually best to construct your walls first before spraying so you don’t have to spend time cutting back foam, which is wasteful. Expanding foam will not move your studs out of position and instead just “wrap” itself around the back edges. If you are putting in your outlet and switch boxes before spraying, tape off the insides to prevent foam from expanding into them. You do not need a plastic vapor barrier over the foam before installing a wall covering for the foam’s sake, but some local building codes don’t differentiate between foam and fiberglass so check first before closing up. For basement home theaters, you may want to consider 2” of open cell foam sprayed up to the ceiling to help with sound deadening before you sheetrock it. For extra sound deadening power, add a layer of rock wool batt insulation to absorb even more sound waves and vibrations.

For projects where it is difficult to move and reposition, make sure you are set up well before spraying. Pulling the hoses to move a tank can cause it to break, and tipping a tank during spray can cause a quick loss of pressure.

Recommended product for basement and crawlspace projects