Demilec Spray Foam Insulation in San Antonio: What to Know First
We provide independent Demilec spray foam insulation service across San Antonio, typically scheduling most jobs within 2 to 4 business days. Whether you have open-cell foam in your attic walls or closed-cell against the roofline, we will give you an honest assessment and upfront pricing before any work starts. If you own a home with Demilec foam and you suspect a problem or you just want a second set of eyes on it, call us at (866) 751-4428 and a live person answers, day or night.
This page is for San Antonio homeowners who already have Demilec spray foam or are considering it and want to know how it actually performs here after ten or fifteen years of Texas heat. We are not affiliated with Demilec or authorized by them, and we will tell you straight what that means for your warranty and your options.
How Demilec Products Fail, and How We Fix Them
Demilec makes solid foam products, but San Antonio’s climate exposes weaknesses that a brochure will not mention. Here is what we actually see, by product line:
- Sealection 500 (open-cell) shrinkage at the roofline. Sealection 500 is soft, forgiving foam, but when it is applied too thin in a hot attic it can pull away from the roof deck over several summers. Air sneaks through those gaps and the homeowner notices the upstairs bedrooms never cool down. Our fix is to cut out the pulled-away sections, prep the surface, and reapply a compatible open-cell foam, then verify coverage with a thermal camera.
- Heatlok HFO Pro (closed-cell) lift-off from metal surfaces. Heatlok HFO Pro is a closed-cell workhorse, but on metal framing or metal roof decks it sometimes lifts if the metal was not scuffed or if it was applied over light surface rust. The telltale sign is a hollow, drum-like sound when you tap the area. We grind the metal clean, remove the loose foam, and reapply a properly bonded layer.
- Sealection Agribalance odor retention in enclosed spaces. Agribalance is a bio-based open-cell product, and in tightly sealed San Antonio homes with no mechanical ventilation, it can hold a musty smell that never fully airs out. Most companies will tell you to just live with it. We will strip the affected area and replace it with a low-odor closed-cell or a different open-cell formulation, depending on your air sealing needs.
- Heatlok Soy poor adhesion to old blown-in residue. This one is common in retrofit jobs. If Demilec foam is sprayed over a dirty attic floor that still has blown-in fiberglass dust or rodent droppings, the foam will not grab, and within a year you get loose chunks and air leaks. We pull up the bad section, vacuum the substrate properly, and reapply. The prep work matters more than the spray.
- Sealection 500 delamination at the rim joist. In San Antonio crawl spaces and basements, rim joists deal with a lot of humidity swings. Sealection 500 can absorb moisture over time and start to crumble at the edges. We replace it with Heatlok HFO Pro or another closed-cell product that handles that damp environment better, and we recommend checking your crawl space ventilation while we are in there.
Our Demilec Spray Foam Insulation Process
Here is how a typical Demilec job goes when you call Walt’s Insulation:
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You call, a person answers. No menu tree, no call center. We ask what you are seeing, what product you have if you know it, and how long the problem has been going on.
- 2
We inspect the foam. A tech who works with Demilec products every week comes to your home, goes into the attic or crawl space, and checks adhesion, density, moisture, and coverage. We do not guess from the driveway.
- 3
We tell you what is actually wrong. If it is a manufacturer issue, we say so. If it is an installation issue from a previous contractor, we say that too. You get a straight answer, not a sales pitch.
- 4
We decide on the fix together. For Demilec work, we use the right foam for the job. Sometimes that means matching the existing product line, and sometimes it means recommending a different formulation that will hold up better in your specific attic. We quote parts and labor separately so you see exactly what you are paying for.
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We do the work and verify it. Once the foam is in place, we check it with a thermal camera and an adhesion test where it matters. We do not leave until we are satisfied it is right.
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The Done Right Promise. Every job we do, including Demilec repairs and installs, is covered by a lifetime workmanship guarantee. If it is not done right, we come back and make it right. No fine print, no runaround.
What Demilec Spray Foam Insulation Costs in San Antonio
Spray foam pricing in San Antonio depends on the product, the square footage, and the condition of the existing substrate. Here are realistic ranges for the Demilec work we do most often:
- Open-cell Sealection 500 attic walls or roofline: $1.80 to $2.60 per board foot
- Closed-cell Heatlok HFO Pro rim joist encapsulation: $2.80 to $3.80 per board foot
- Closed-cell Heatlok HFO Pro garage ceiling: $2.50 to $3.50 per board foot
- Small spot repair (under 200 board feet, any Demilec product): $400 to $900
- Full removal of failed Demilec foam and reinstall: $4 to $7 per square foot of affected area
What moves the price most is access. If your attic is tight or your crawl space requires working on your back, it takes longer and costs more. Prep work, like vacuuming old insulation or grinding rust off metal, adds labor and materials but it is the difference between foam that lasts and foam that fails in three years. We always quote the job before we start, and if you have a written estimate from another contractor, we will give you a free second opinion on it. Call (866) 751-4428 for an exact number.
Why San Antonio Homeowners Call Walt’s Insulation for Demilec Work
We have been doing insulation work here since 2000, and Demilec foam has been on enough of our trucks over the years that our techs know the product lines by feel. We are the one down the road, not a franchise with a rotating crew. Walt Brenner started this business after watching too many San Antonio homeowners get sold foam systems that were not right for a climate where attics hit 140 degrees in July, and we still run it the same way: tell the truth, use the right material, and stand behind the work.
If Demilec is not the right fit for a particular job, we say so and we offer alternatives. We also work with other brands including Owens Corning, Rockwool, Icynene, Johns Manville, CertainTeed, Knauf, and GreenFiber, plus Reflectix for radiant barrier applications. You get an honest recommendation, not whatever we happen to have in the warehouse. Every technician who walks into your home is background-checked and in uniform, so you know exactly who you are letting in. We answer the phone live, 24/7. Talk to a real person, get a straight answer.
FAQs
It can, and we will tell you that plainly before any work begins. Demilec warranties are handled through the manufacturer and typically cover product defects, not installation errors. As an independent Demilec service provider, we are not part of their warranty network, so any repair we do is not automatically covered by Demilec. What we do cover is our own workmanship, for life, through the Done Right Promise. If you want to pursue a Demilec warranty claim, we can help you document the issue. Call (866) 751-4428 and we will walk you through what we find.
Most Demilec inspections in San Antonio are scheduled within 2 to 4 business days, and we keep emergency slots open for situations where the foam is actively failing and air or moisture is getting into your home. If you need someone today, call (866) 751-4428 and ask. A live person answers, and they will tell you what is actually available, not what a call script says.
For isolated failures, like a rim joist section or a small roofline pull-away, repair is almost always cheaper than replacement and can run $400 to $900. If the foam is failing across a large area, you are often better off replacing the whole thing, because patching over widespread adhesion failure just delays the next problem. We will give you numbers for both options and let you decide.
In most cases, yes. Sealection 500, Heatlok HFO Pro, Sealection Agribalance, and Heatlok Soy are all products we have worked with, and we can source the same line if that is what the job calls for. In some cases, we will recommend a different product if your situation calls for it, and we will explain why in plain language before you spend a dollar.
Open-cell foam like Sealection 500 is vapor permeable, which means it can absorb moisture in high-humidity conditions and hold it if the space is not ventilated properly. In a San Antonio attic or crawl space that stays damp, that can lead to odor or gradual breakdown. We check moisture levels during every inspection and we will tell you if your specific space is a bad candidate for open-cell foam. If it is, we will recommend a closed-cell alternative like Heatlok HFO Pro and quote both options.
Written by Walt Brenner, Owner, Walt’s Insulation at Walt’s Insulation, serving San Antonio and nearby areas.