How to Protect Your Foam Insulation with a Fire Barrier

What You'll Need
Fire board
Utility knife
Measuring tape
Drywall mud (joint compound)
Drywall tape
Drywall saw
Screw gun
Drywall screws
Mud pan
4-inch mud knife
8 or 10-inch mud knife
Drywall sander

A fire barrier is a general term that is used to describe any building material that is approved by building codes to slow the spread of a fire from one area, or fire zone, of a home or building to another. In many cases, particularly that of the interior of a home, this is typically in the form of gypsum board (otherwise known as drywall or sheet rock) with a thickness of at least 1/2 an inch. There is a particular type of drywall that is referred to as fire board. This special type of drywall has a has a higher moisture content in the gypsum composite. As this material is heated, the moisture is drawn out to retard the spread of the fire. This simple technique will retard a fire for fifteen minutes or more. Installing this drywall is the same technique as installing general drywall. Here is what you will need.

Step 1 - Determine Amount Needed

First, you will want to measure the area to be covered to determine the amount of fire board that is needed to cover the space. To get the area, measure the height and width of the area and multiply it. Convert this measurement to square feet by dividing any measurements in inches by 12. A standard sheet of fire board is 24 square feet (8 by 4 feet). Divide your area by 24 to determine how many sheets of fire board you will need.

Step 2 - Cut Board

Cut the drywall to the specific sizes that you will need. Install sheets whole where ever it is possible. It is easiest to install drywall with at least two people, but three is best. Two people can hold the sheets in place while the third secures the sheet with screws. Drive the screws through the drywall and into the wood studs behind the sheet rock, sinking the heads slightly below the level of the drywall. Joints in between pieces of sheet rock should only occur over studs, and the joints should be made as tight as possible. 

Step 3 - Tape Joints

Put some of the mud into a mud pan. If needed, mix the mud with a little bit of water so that it has the consistency of pudding. Spread a layer of mud about an 1/8- inch thick over a joint. Press joint tape into the mud, and then layer another coat of mud over the tape. If you are inclined, there is a tool referred to as a banjo that will dispense mud coated tape that makes this process easier, but this way works too. Smooth out the joint with the larger knife, scraping away excess mud. Get it as clean as possible, but do not overwork it. Work quickly so that the mud doesn't get overly dry. Coat all screw heads with a thin coat of mud as well. 

Step 4 - Finishing

Sand all mudded areas and reapply any areas that have depressions or gaps. Prime and Paint as desired.