How To Insulate Your Basement Walls To Prevent Moisture And Temperature Problems From Arising

7 March 2016
 Categories: Construction & Contractors, Articles


Basements can be notoriously damp and chilly, even in the summer months, if the walls aren't properly insulated. The easiest time to insulate a basement is before the studs are installed, so if your basement is still unfinished, you have a great opportunity to do the job right. Below is more information for homeowners or other do-it-yourselfers who want to insulate their basements the right way:

Tools and materials you will need

  • ¾-inch thick rigid foam insulation sheet (four-foot by eight-foot in size)

  • Mineral wool insulation (16-inch wide rolls)

  • Vapor barrier roll

  • Vapor barrier tape

  • 2-inch fluted masonry nails

  • ⅛-inch inside diameter fender washers

  • Claw hammer

  • Utility knife

  • Straight edge

  • Scissors

  • Serrated knife

  • Measuring tape

Installing the insulation

1. Measure and cut the rigid foam insulation - The first step is to attach the rigid foam insulation directly to the concrete walls. Though the foam board has a limited R-value, the measure of its insulating characteristics, it is important to place it before any studs are built. The reason is that studs directly adjacent to the concrete wall will transfer heat from your basement into the cooler walls, then into the surrounding earth. Thermal transfer can make keeping your basement comfortable more difficult and expensive.

When installing the rigid foam insulation, first measure the area of the wall you wish to cover, then trim the pieces of foam to size with a utility knife and straight edge. Be sure to make the cuts as clean, straight and accurate as possible; you don't want any gaps to remain between sections, as these can allow warmth to bleed away.

2. Install the rigid foam insulation sections - Once you have cut the pieces of rigid foam insulation to size, ask a helper to hold them in place where you wish to have them located. Next, locate the approximate middle of the section, then drive a 2-inch fluted masonry nail through a fender washer, through the foam insulation, and into the wall. Don't drive the nail too deeply, or you may crush the foam and lessens its insulating ability. Continue to nail the foam insulation to the wall using masonry nails and washers; space each nail/washer combination approximately 18 inches apart. Finish by driving a nail and washer into each intersection whenever four pieces of foam insulation meet, as this will help hold down the corners and keep the cold from penetrating.

3. Install mineral wool insulation - After the studs have been built, the next step is to line the gaps between studs with mineral wool insulation. Mineral wool, sometimes called stone wool or rock wool, consists of molten stone that is spun into thin, wispy strands, then compacted to form rolls. It is fire-resistant, and it also has excellent insulating characteristics.

To install the mineral wool, begin by unrolling the bundles and cut them using a serrated knife. Then, stuff each strip of mineral wool into the gaps between the studs. Be sure to push the mineral wool all the way into place to prevent it from falling out, and watch out for gaps between ends of strips.

4. Install a vapor barrier - The last insulating step is to install a vapor barrier to prevent moisture transfer between the damp, cold earth and your basement. The vapor barrier is simply a large sheet of thick plastic, but it will keep water out of your basement if installed properly.

To install the barrier, measure and cut the material using the same knife and straightedge as before. With a helper holding the barrier in place over the studs, use vapor barrier tape to attach each piece to the studs and overlap each seam with tape. If necessary, you may staple the vapor barrier to the studs, but you will need to cover each staple hole with the barrier tape.

If you have trouble installing the insulation, contact a professional from a company like Mincin Insulation Service Inc. for help.