How to Install Basement Floor Insulation

Finished basement with carpet
  • 10-20 hours
  • Intermediate
  • 500-2,000
What You'll Need
2x4 pressure treated studs
2-inch galvanized wood screws
3-inch masonry screws
1-1/2-inch rigid foam insulation
3/4 inch tongue and groove sub-flooring

Today, basements are often used as living space, so basement floor insulation requires as much attention as other parts of the house. Unlike yesteryears when it was used as storage space for grains and other food supplies, basements are now wall to wall carpeted corner bars where friends and family gather for conversations over a few drinks, or a TV room where a game of baseball, basketball, or soccer is thoroughly enjoyed on the big LCD screen. Whichever purpose it may serve, basement floor insulation is essential to keep homes cozy and comfortable in every season. The process involves the creation of an insulation layer between the ground and concrete floor. The insulation barrier traps warm air and keeps moisture at bay. Subsequently, the space gets rid of dampness and moldy smell. For a budget friendly insulated basement floor we walk you through the following process:

Step1 - Check for Water Infiltration

Insulating a basement that allows water to stand during winters is a pure waste of time, effort and money. The water will ruin the insulation and wood framing around it. Resolve the water infiltration challenge before moving ahead. Look both outside and inside the basement for drainage solutions.

Step 2 - Purchase Concrete Sealer

spreading finish on concrete flooring

The concrete floor slab must be sealed before the insulation process. Visit any home improvement store and purchase a top quality concrete sealer. Invest wisely because this is the last chance to secure the slab effectively, else the insulation process will render null & void after sometime.

Step 3 - Clean Concrete Slab Prior to Sealing

It is essential to thoroughly clean the concrete slab of dust and debris prior to applying the concrete sealer. The process involves a roll-on application and requires 24 hours wait between the coats.

Step 4 - Frame the Floor

Pressure treated lumber is the best option for extending the life of the floor framing.

Install 2x4 pressure treated sleepers with flat side down atop the concrete. Fasten them with three-inch masonry screws at every couple of feet. Next run these sleepers every 16-inch on center; spanning from wall to wall. The finished product will resemble a grid. Nail the ends of the sleepers into the previously installed rim pieces.

Step 5 - Install Foam Insulation

rigid foam in a stack

Install rigid foam insulation in the bays between the sleepers. Rigid foam insulation is resistant against the natural dampness present in concrete. Rigid foam insulation is available in 15 and 23-inch wide boards. Purchase 15-inch foam board for use on 16-inch floor framing. Employ a utility knife to cut the boards to desired lengths.

Step 6 - Install and Screw the Plywood

Install ¾ inch tongue and groove plywood atop sleepers. Secure the sleepers with galvanized or stainless steel two-inch wooden screws every eight-inches on center. It is important to use only wooden or galvanized screws; regular screws will dissolve in chemically treated wood.