Stop Cold Floors and Basement Drafts

Below grade insulation for basements and crawlspaces in Naperville, Illinois

If your floors feel cold in the morning or drafts move through your basement, you are losing conditioned air through uninsulated walls and rim joists. Many homes in Naperville have unfinished or partially finished basements that were never properly insulated, which means your heating system works harder than it should during the winter months.

Windy City Insulation installs below grade insulation designed to address cold floors, drafts, and moisture-related problems common in below-ground spaces. We focus on rim joists, foundation walls, and crawlspace perimeters where heat loss happens most often. This service is frequently paired with air sealing to close gaps along sill plates and utility penetrations, which prevents humid air from entering in summer and cold air from infiltrating in winter.

Contact us today to discuss your basement or crawlspace insulation needs in Naperville.

Where the insulation goes and why it matters

We apply closed-cell spray foam or rigid foam board to foundation walls and rim joist cavities in your Naperville home, creating a continuous thermal barrier between the conditioned space and the surrounding soil or exterior air. The material fills gaps and seals off areas where moisture and cold air typically enter.

After the work is finished, your floors above the basement will feel warmer, drafts along the perimeter will stop, and you may notice your furnace runs for shorter cycles. Basements that were previously damp or musty often feel drier because the insulation helps control condensation on cold surfaces.

We can also insulate crawlspaces that are vented or open to outside air, sealing them off from the ground and exterior walls. This service does not include foundation repair or drainage work, but it does prepare the space for better long-term comfort and reduced energy use once the thermal envelope is sealed.

Questions homeowners ask before scheduling

Homeowners often ask how below grade insulation affects moisture, how long the work takes, and what preparation is needed before the crew arrives. Below are answers to the most common questions we hear during consultations.

What areas get insulated during below grade work?
We insulate rim joists, foundation walls, and crawlspace perimeters where heat loss occurs most often. The exact areas depend on whether your space is finished, unfinished, or only partially enclosed.
How does insulation help with moisture problems?
Insulating cold surfaces reduces condensation that forms when warm indoor air contacts cool foundation walls or rim joists. This keeps the space drier and prevents mold growth on wood framing and floor joists.
How long does basement insulation take to install?
Most basement insulation projects in Naperville take one to two days depending on square footage and access. Crawlspace work is often faster if the area is clear and the ceiling height allows for equipment.
What should I do to prepare the basement or crawlspace?
You should remove any items stored along the perimeter walls and clear access to the rim joist area. If your crawlspace has standing water or drainage issues, those need to be resolved before insulation can be installed.
Why is rim joist insulation important in Northern Illinois?
Rim joists sit at the transition between your foundation and floor framing, and they are one of the biggest sources of air leakage in older homes. Sealing and insulating this area stops cold air from entering and reduces drafts along interior floors.

Windy City Insulation is a fully insured contractor serving Naperville and the surrounding area, and we focus on long-term performance in below-grade spaces where moisture and temperature control matter most. Get in touch to schedule a consultation and review your insulation options.