A Step-by-Step Guide to Finishing a Basement

The tools needed to complete your project largely depend on the materials you choose to install, but you can count on likely needing the following: a circular saw, a caulk gun, a hammer, a nail gun, nails, a tape measure, a masonry drill, insulation adhesive, and utility knives. You should also have the proper safety gear, like gloves and goggles, on hand to protect yourself throughout the renovation. 

Things to Consider Before Starting Your Basement Renovation 

Before starting your renovation, you’ll need to apply for building permits and check your local building code. If your basement doesn’t meet code for ceiling height or exits, you’ll likely have to bring in professional reinforcements to help you complete your project.  

Your local building code will also outline rules and special considerations concerning vapor barriers, fire performance, and more, which may affect the materials you buy and the steps you need to take to finish your basement. When in doubt, consult a professional contractor for guidance. 

While planning your renovation, you should also test your basement for moisture, humidity, and dampness. If the levels are high, you’ll likely need to take steps to waterproof the area and also choose materials that are water and moisture resistant. 

Steps to Finish Basement Walls

Your basement walls will require the most work to finish, as you’ll need to insulate and frame them before installing wall panels or drywall. 

How to Insulate Your Basement Walls 

If you’re handling your basement reno without any outside help, rigid foam insulation is a great, DIY-friendly, and moisture-resistant option to insulate your basement. Several companies sell rigid foam insulation, but you’ll find their installation processes are very similar and commonly include the following steps: 

• Caulk all the seams between ceiling and rim joists with silicone caulk. 
• Measure the wall from the floor to the ceiling and mark the measured height on the rigid foam panel. Using a utility knife, score the panel and snap the board along the scored line.  
• Apply a spray foam adhesive to the back of the rigid foam insulation panel, especially in the corners and along the edges.  
• Place the panel against the wall and push firmly. Cut the next panel and place it securely next to the first one.  
• Continue to install the panels along the walls following steps one through four, making sure to mark and cut out areas for electrical outlet boxes before installing. 
• Cover seams with tape and fill in large holes or cracks with low-expanding spray foam. 

If your wall studs have already been installed, you’ll likely want to opt for fiberglass insulation or spray foam insulation instead: 

• Fiberglass insulation is sold in batts or rolls that are designed to fit standard walls and ceilings with framing spaced 16 or 24 inches apart on-center. It’s easy to install yourself, however, fiberglass insulation can trap moisture and lead to mold or mildew growth. 
• Spray foam insulation is a polyurethane foam that’s sprayed in the space between basement wall studs with a hose and gun and then expands. While we recommend hiring a certified contractor or technician to install spray foam, you can buy do-it-yourself kits online or at your local hardware store. During installation, be sure to follow the instructions provided with your kit from the manufacturer. 

How to Frame Your Basement Walls 

Once you’ve installed the insulation, it’s time to frame your walls. This is an important step that must be completed before installing wall panels or drywall: 

• Draw a chalk line on the floor four inches from the wall. 
• Measure the length of your wall and cut two 2x4s to size — these will be your top and bottom plates. 
• Subtract 3 inches from the previous measurement and cut your studs to size. This accommodates the thickness of the two 2x4 plates, which are 1 ½” each. 
• Set the top and bottom plates side by side on the floor to mark spacing for the studs. The first stud will be offset by ¾”. Mark every 16” to indicate the centers of the studs.  
• Place your bottom plate along the bottom of the wall, aligning it with the chalk line drawn in the first step. Secure the bottom plate using a masonry drill and nails, adding a supporting nail at each 16” mark. 
• Using a nail gun instead of a masonry drill, install the top plate by following the same instructions for the bottom plate. If your ceiling joists run parallel to the top plate, add a blocking board between the nearest joists every 16 inches to attach the top plate to. 
• Align the studs with the 16-inch marks made earlier and insert nails on each side of the stud at a 45-degree angle. 
• Repeat steps one through seven until all your basement walls have been framed. 

Before installing wall panels or drywall, you’ll want to complete any electric, plumbing, or air duct work that will run inside the walls. This part of your project should not be DIYed. Hire a certified professional to complete it for you.