Serving Northern IL & Chicago Suburbs

Rim Joist Insulation In Northern IL, Rockford, Chicago Suburbs & Southern WI

What Is A Rim Joist?

Joists are the main elements that create the frame of a home’s ceiling and floor. Generally, ceiling and floor joists are built out of engineered or 2x lumber. The joists are placed about 16 inches on center apart. The wood that wraps around the edge of the floor framing is called the rim joist or band joist. Looking at the outside of a home as it is being framed, the rim joist is the solid band of lumber spanning along the side of the floor frame.

The main purpose of a rim joist is to give stability and strength to the other floor joists. Floor joists are held into the rim joists by nails which prevent the boards from falling over to the side and tie the flooring system together. The rim joists keep the floor joists upright and level.

Rim Joists

Why Are Rim Joists Important To Insulate?

Many homes are improperly insulated on the rim joists, allowing cold air around the foundation to easily enter the home. Insulating rim joists prevents drafts, cold temperatures, moisture, mold, pests and structural damages.

When a home has uninsulated rim joists, the only layer between the interior and exterior of the home is the housewrap, sheathing (which is only about 1/2 in – 3/4 in thick) and the siding. Rim joists are considered above grade and should be insulated to a minimum of R-20 in climate zones 5-8 and a minimum of R-13 in climate zones 1-4. Rim joist insulation is now required by most current building codes.

What Is The Best Product For Rim Joist Insulation?

The most common products used for rim joist insulation are foam board and spray foam. Each product has unique benefits and differs in cost. Read below to learn more and decide which product is best for your home. Also, feel free to contact our certified technicians for a free quote and assessment for your rim joist insulation. Call: (833) 244 -7283.  

Why Choose Our Team?

1. Professional Service

All Comfort 1st Insulation technicians are certified, insured, knowledgeable of current building codes, fully trained and punctual. 

2. Warranty

All services performed by Comfort 1st Insulation are warrantied as a promise to our customers that the job is always done right the first time.

3. Customer Satisfaction

Comfort 1st Insulation is devoted to improving our customer’s energy efficiency and comfort through insulation services. The work is never completed until the customer is satisfied!



1. Call Us

Consult with a Home Performance & Insulation Contractor for your free estimate and consultation.

2. Free Quote

Once you reach out, we’ll work with your schedule to plan an appointment for an expert to assess your home and provide an estimate.

3. Do the Work

After the assessment, you’ll be given a quote and we can proceed with performing work on your home.

4. Start Saving

Once the insulation work has been completed, you’ll notice decreasing utility bills, increased efficiency of the home, and greater comfort.

Certifications And Affiliations

Comfort 1st Insulation provides quality insulation services with expertise that can be clearly seen in our photo gallery. Review our work and if you would like any further information or have questions, please fill out our contact form and a member of our certified team can reach back out to you!

Who Can Help Me Install Rim Joist Insulation?

Curious about insulation installation for your home or place of work? Comfort 1st Insulation provides professional insulation services in Northern Illinois, the Chicago suburbs, the greater Rockford area, and southern Wisconsin. Give us a call at (833) 244-7283 to have one of our professionals inspect your attic. Have any inquiries for your Rockford area home or business? Please fill out our contact form to get ahold of the experts at Comfort 1st Insulation or email us at

Recieve A Free Insulation Consultation!