Demilec Attic Cleaning & Rodent Proofing in San Antonio: What to Know First
We provide independent Demilec attic cleaning and rodent proofing in San Antonio, and most jobs wrap up within one to two days depending on how much damage rodents have done to your spray foam. You’re looking at roughly $1,200 to $3,800 for a full cleanout, sanitizing, and exclusion job on a typical San Antonio home, though smaller spot treatments run less. This page is for homeowners who had Demilec spray foam installed in their attic and are now dealing with rodent activity, odors, or just years of dust and debris sitting on top of that foam. If you’ve got critters in your Demilec insulation, call (866) 751-4428 and a real person will answer.
How Demilec Products Fail, and How We Fix Them
Demilec makes solid spray foam, but San Antonio attics punish insulation in ways the product data sheets don’t prepare you for. Here’s what we actually see on Demilec jobs across the city, from Stone Oak to Alamo Heights, and what we do about it.
- Heatseal OC and rodents don’t mix. Demilec’s open-cell Heatseal OC is soft and porous. Rodents tunnel through it like it’s cotton candy. We regularly find rat runs carved straight through 6 inches of Heatseal OC in North San Antonio homes, especially where the foam meets roof decking gaps. The fix starts with full exclusion, then we remove the damaged sections and re-foam or re-insulate so your thermal envelope stays intact.
- Sealection 500 absorbs odor and holds it. The open-cell structure of Sealection 500 means when rodents nest in it, urine and droppings soak deep into the foam. You can’t just spray a sanitizer on the surface. We cut out affected sections, treat the decking underneath, and reapply compatible material. Surface-only cleaning on Sealection 500 just leaves the smell locked inside.
- APEX and Heatlok HFO failures at the roofline. Demilec’s closed-cell products, including APEX and Heatlok HFO, can separate from the roof deck when the installer didn’t account for San Antonio’s thermal swings. Rodents exploit these gaps and build nests right in the void. We find this a lot in older Alamo Heights and Terrell Hills roofs where decking flexes. We seal the gap, then address the rodent entry point that let them in.
- Attic exhaust fans buried in foam. San Antonio homes with Demilec foam often had the installer spray right around roof vents and exhaust fans. When those fans fail, the fix requires cutting away foam, and if rodents found the same opening, you’ve got double trouble. We clear the foam, repair or replace the fan, and rodent-proof the penetration before re-foaming.
- Over-spray on trusses hides rodent damage. Demilec installs sometimes leave foam overspray on trusses and rafters. That overspray masks gnaw marks and structural damage from rodents. During every Demilec attic cleaning, we strip back that overspray in key load paths so we can see what the rodents actually chewed. Better to find a weakened rafter in May than in October when you’re putting up Christmas lights.
Our Demilec Attic Cleaning & Rodent Proofing Process
This is how a Demilec job goes at Walt’s Insulation, start to finish. No vague promises, just what we do when we’re in your attic.
- 1
Call and talk to a person. You call (866) 751-4428. A live person answers, asks about your attic, and schedules a visit. We don’t route you to a call center in another state.
- 2
Attic inspection and Demilec assessment. Our technician walks your attic, identifies which Demilec line you have, checks for rodent entry points, nesting areas, and foam damage. We look at the roof deck, eaves, vents, and pipe penetrations.
- 3
Straightforward quote. You get one number for the work we discussed. We don’t pad it with surprise line items after we start.
- 4
Cleanout and sanitizing. We remove rodent-contaminated insulation, droppings, nesting material, and dead pests. We treat affected surfaces with an antimicrobial cleaner and deodorizer so your attic doesn’t smell like a barn in August. Where Demilec foam is damaged beyond saving, we remove those sections.
- 5
Rodent proofing and exclusion. We seal every entry point we found, from quarter-sized soffit gaps to chewed corners at roof junctions. We’re not setting traps and hoping for the best; we’re closing the doors so they can’t get back in.
- 6
Restore and verify. We re-insulate where needed, re-foam if you want that Demilec performance restored, and walk you through what we did. Then our Done Right Promise kicks in: if it’s not done right, we make it right. That’s not a sales line. That’s the deal.
What Demilec Attic Cleaning & Rodent Proofing Costs in San Antonio
Here are the numbers we quote on real Demilec jobs in San Antonio. Prices move based on attic size, how much foam has to come out, and how many entry points need sealing.
| Job Scope | Typical Range |
|---|---|
| Basic Demilec attic cleanout, no major rodent damage | $1,200 – $1,800 |
| Cleanout + full sanitizing + deodorizing | $1,800 – $2,600 |
| Full restoration: cleanout, sanitizing, exclusion, damaged foam removal | $2,600 – $3,800 |
| Rodent entry point sealing only (minor gaps) | $400 – $800 |
The biggest cost driver is how much Demilec foam the rodents destroyed. Open-cell lines like Heatseal OC and Sealection 500 absorb contamination faster than closed-cell APEX or Heatlok HFO, which means more removal and more replacement material. Every quote starts with a free estimate, and if another company gave you a written estimate, bring it. We’ll give you a free second opinion on it.
Why San Antonio Homeowners Call Walt’s Insulation for Demilec Work
Walt Brenner started this business in 2000 after watching too many homeowners get sold insulation that wasn’t right for South Texas. He grew up on the north side of San Antonio, learned the trade at San Antonio College, and has spent 25 years crawling through attics that hit 140 degrees in July. We’re not a franchise and we don’t have a call center. We’re the one down the road, with a published address and a license number you can actually look up.
Every job gets a background-checked, uniformed technician who knows Demilec foam and also works with Owens Corning, Rockwool, Icynene, Johns Manville, CertainTeed, Knauf, GreenFiber, and Reflectix. That means we recommend what actually works for your house, not what we’re incentivized to sell this quarter. And every job is backed by the Done Right Promise: if it’s not done right, we make it right. No runaround.
FAQs
Yes, if the foam is intact and contamination is surface-level. We vacuum, treat, and deodorize the foam in place. If rodents nested inside open-cell Demilec lines like Sealection 500 or Heatseal OC, those sections usually have to come out because the contamination soaks through the foam. Call (866) 751-4428 and we’ll tell you which situation you have.
As an independent Demilec service provider, we can’t speak for Demilec’s warranty department. But we’ve been doing this long enough to know that rodent damage is typically excluded from manufacturer warranties anyway. What we do is document everything, take photos, and leave your attic cleaner than we found it. If you’re worried about warranty specifics, call Demilec directly and ask. Then call us for the actual work.
Same week in most cases. If you’ve got active rodents, we prioritize you because every day they’re in there means more foam destroyed and more droppings piling up. Call (866) 751-4428 and a live person will get you on the schedule.
Usually not. Full re-foam on a San Antonio attic runs $5,000 to $12,000 depending on square footage. Cleaning, sanitizing, and rodent proofing typically costs a third to half of that when most of your Demilec foam is still good. We’ll tell you straight if your foam is worth saving or if you’re throwing good money after bad.
Yes. Seniors and veterans get 10% off, always. We also take $40 off any repair over $200, and there’s no trip charge inside our service county. Call (866) 751-4428 for a free estimate and we’ll apply every discount you qualify for.
We answer the phone live, talk to a real person, get a straight answer.
Written by Walt Brenner, Owner, Walt’s Insulation at Walt’s Insulation, serving San Antonio and nearby areas.