Attic Spray Foam Insulation Wentzville, MO 63385 | St Louis Spray Foam Insulation

Wentzville is growing fast along Interstate 70, and that growth is bringing new homes, new subdivisions, and new insulation challenges across ZIP 63385. Whether you live in one of the newer two-story homes with vaulted great rooms and bonus rooms over garages, or you own acreage west of town with a pole barn or metal building, spray foam insulation and air sealing are the most effective tools we have to keep your home comfortable year-round and your utility bills under control.

St. Louis Spray Foam Insulation has been serving Wentzville and the surrounding St. Louis area since 2012. We understand the mixed-humid climate that drives moisture into your walls in summer and out through your attic in winter, and we know how to seal and insulate the spaces that matter most: attics that bake at 130 degrees in July and freeze in January, crawl spaces and rim joists where cold air sneaks in, closed walls with no cavity insulation, and the metal buildings and barndominiums that sweat in spring and frost in winter.

Spray Foam Insulation in Wentzville (63385)

Wentzville's newer subdivisions sit on basements and crawl spaces with rim joists and band joists that leak cold air and heat in equal measure. The two-story homes with walkout basements and bonus rooms over garages create ductwork routed through unconditioned attics, and those attics are where most of the comfort and energy problems start. In summer, outdoor humidity drives moisture inward through any gap in the thermal envelope. In winter, warm indoor air escapes upward and condenses on cold attic surfaces. Closed walls in the 1980s-2000s construction that dominates Wentzville were never insulated, and they stay that way unless you inject foam into them. Beyond town, the pole barns, metal shops, and barndominiums that dot the acreage west of Wentzville face their own challenges: metal buildings conduct heat and cold directly, and without proper air sealing and insulation, they become expensive to condition and prone to condensation on the interior when the seasons change.

Our team has spray-foamed attics, crawl spaces, rim joists, and metal buildings across Wentzville and the St. Louis area for over a decade. We know the access challenges of tight attics and low crawl spaces, the importance of proper ventilation during cure, and how to specify the right R-value and thickness for your climate and building code. We show up with a written estimate that names the R-value, the thickness, the square footage or board footage, and the cost. No surprises.

Our services in Wentzville

Attic Spray Foam Insulation in Wentzville · Open-cell roof-deck foam turns an attic that bakes at 140°F in July and freezes…
Closed Cell Spray Foam Insulation in Wentzville · Two-pound closed-cell foam delivers R-6.5 per inch with its own vapor retarder…
Open Cell Spray Foam Insulation in Wentzville · Half-pound open-cell foam air-seals attics and walls at a friendlier price per…
Wall & Injection Foam Insulation in Wentzville · Injection foam fills closed frame walls through small drilled ports…
Crawl Space Spray Foam Insulation in Wentzville · Closed-cell foam on crawl space walls and subfloors ends the cold floors of…
Rim Joist & Band Joist Spray Foam in Wentzville · Basement rim joists leak more cold air than almost anything in a St. Louis…
Garage Spray Foam Insulation in Wentzville · Garage ceilings under bonus rooms and walls shared with the house are…
Metal Building & Barndominium Spray Foam in Wentzville · Closed-cell foam stops a Missouri metal building from sweating in spring and…
Commercial & New Construction Spray Foam in Wentzville · Warehouses; offices; churches and production builders served on schedule.
Insulation Removal in Wentzville · Old blown-in and batts vacuumed out before any new foam goes in, never buried.
Insulation Replacement & Re-Insulation in Wentzville · The full reset: old material removed; gaps air-sealed…
Air Sealing in Wentzville · Top plates; can lights; chimney chases and attic hatches leak more heated and…

How a Job Works in Wentzville

We start with a free on-site assessment. You call us at (314) 912-1801 or request an estimate online, and we visit your property in Wentzville to see what we are working with: the attic access, the crawl space clearance, the walls we can reach, any existing insulation that has to come out, and any moisture or damage we have to address before any foam goes in. We walk the space with you, ask questions about comfort, moisture, and utility costs, and then we give you a written estimate with R-value and thickness specs so you know exactly what you are paying for and what you will get.

On the day of the work, our crew sets up mechanical ventilation, masks off areas that need protection, and sprays the foam in controlled passes to the thickness and density the estimate calls for. For attics in occupied homes, we observe a twenty-four to forty-eight hour re-entry window after cure is complete. If your home is empty, we can accelerate the timeline. If we are removing old insulation first, we coordinate that work carefully to keep dust and debris contained, and we haul it away. If we are sealing rim joists or crawl spaces, we work from inside the basement or crawl space to minimize disruption to your yard and landscaping.

When we are done, we clean up, do a final walkthrough with you, and leave your property ready to use. No mess, no lingering odor if the work was done right, and a property that is measurably more comfortable and efficient.

Pricing for spray foam insulation in Wentzville depends on the scope of work. Attic foam typically runs from $1.50 per square foot for open cell to $1.20 per board foot for closed cell, depending on the R-value and thickness your attic needs. Wall injection foam for closed cavities starts around $2 per square foot. A crawl space job with rim joist sealing and floor foam usually runs $2,500 and up, depending on the square footage and whether we are removing old insulation first. If you have contaminated or failed insulation that has to come out, add $950 to $1,200 for removal, or more if the space is large or access is tight. The big variables are always the area to cover, the R-value you want to achieve, whether you choose open cell or closed cell foam, and what has to be removed or repaired before we spray. We give you a written estimate with all of those numbers spelled out. Call us at (314) 912-1801 for a free estimate, and we will walk you through the cost factors specific to your job.

✅ Written Estimates with R-Value & Thickness Specs, fully insured for work in Wentzville and nearby areas.

I have a bonus room over my garage in Wentzville, and it is always cold in winter and hot in summer. What is the problem?

The garage ceiling is almost never insulated properly, and the walls around the bonus room are often open to the attic or have gaps in the thermal envelope. Cold air from the unheated garage below rises into the bonus room, and in summer, heat radiates down from a hot attic above. Spray foam on the garage ceiling, the rim joists where the room sits, and any exterior walls in the bonus room will seal those air leaks and add R-value where you need it most. We can also seal and insulate the attic above the room if that is where the heat is coming from. A written estimate will show you exactly where the heat loss is happening and what it will cost to fix it.

I see condensation on the rim joist in my Wentzville basement in spring and summer. Is that normal, and what do I do before spray foam goes in?

Condensation on a rim joist or band joist in spring and summer is a sign that humid outdoor air is leaking into the basement and hitting a cold surface. That moisture has to stop before any foam goes on the rim joist, or the foam will trap water against the wood and cause rot. We inspect the rim joist and the band joist carefully, check for any active water intrusion or seepage, and if we see moisture, we do not spray until the source is fixed. That might mean grading away from the foundation, sealing a crack, or improving drainage around the perimeter. Once the rim joist is dry, we seal and insulate it with spray foam, and the condensation problem goes away. Call us at (314) 912-1801 if you are seeing moisture, and we will tell you what has to happen first.

How much does it cost to remove old insulation from an attic in Wentzville and replace it with spray foam?

Insulation removal typically runs $950 to $1,200 for a standard attic, depending on how much insulation is there and how easy it is to access and haul out. Once the attic is clean, spray foam usually costs $1.50 per square foot for open cell or $1.20 per board foot for closed cell, depending on the R-value you want. A 1,500 square foot attic with removal and closed cell foam to R-38 or R-49 will typically run $3,500 to $5,000, but every job is different. We give you a written estimate with the removal cost and the foam cost spelled out separately, so you know exactly what you are paying for. Call (314) 912-1801 for a free estimate.

What R-value and thickness do I need in my Wentzville attic, and who decides that?

The energy code in force at your address in Wentzville (63385) sets a minimum R-value for attic insulation, and that code is adopted and enforced by the City of Wentzville building department. The thermal barrier and ignition barrier requirements are also set by code and vary depending on the foam type and thickness. We do not set those rules, the building code does, and the building inspector enforces them. When we give you a written estimate, we specify the R-value and thickness that will meet the code at your address, and we can help you navigate what applies at your property. Check the City of Wentzville website at https://www.wentzvillemo.gov for permit requirements and contact information for the building department if you have specific questions about what the code requires.

Can I live in my Wentzville home while the spray foam work is happening, and how long before I can use the attic or crawl space again?

Yes, you can stay in your home during the work. We use mechanical ventilation during the spray process to manage off-gassing, and we observe a re-entry window of twenty-four to forty-eight hours after cure is complete before the space is safe to occupy or store items in. That means you can use your home normally, but you should stay out of the attic or crawl space until we give you the all-clear. If your home is empty, we can work without the re-entry restriction. For commercial properties or metal buildings in master-planned areas, we coordinate with any HOA architectural rules that might apply to exterior work. Call us at (314) 912-1801 to discuss the timeline for your job.

Are you insured for spray foam insulation work in Wentzville?

Yes, we are fully insured with general liability and workers' compensation coverage for all spray foam insulation and air sealing work. You can verify our insurance at the time of your estimate. We also recommend that you verify the insurance of any contractor you hire, including us, before work begins. Ask for a certificate of insurance and confirm that the coverage is active and sufficient for the scope of work.

Is summer or winter the best time to schedule spray foam insulation in Wentzville?

We work year-round in Wentzville, but the timing depends on what you are trying to fix. If your air conditioning bills are out of control in summer, the problem is usually heat leaking into your attic or a bonus room, and you will feel the benefit immediately once that is sealed. If you are cold in winter, rim joist and crawl space sealing will make the biggest difference. The mixed-humid climate in Wentzville means moisture is always a concern, so spring and fall are good times to address crawl space and basement rim joist work before the humid season hits or the cold season begins. We can schedule you quickly, so call (314) 912-1801 and let us know what is bothering you, and we will fit you in.