Demilec Attic Insulation Nationwide

Demilec Attic Insulation: The San Antonio Owner’s Guide

If you have Demilec spray foam in your San Antonio attic and it’s peeling, cracking, or pulling away from the roof deck, we stock Demilec-compatible insulation and can typically repair or re-insulate the affected area within 48 hours. Installed pricing for Demilec open-cell or closed-cell attic work in San Antonio runs $1,800 to $6,400 depending on square footage, existing foam condition, and whether we’re spot-repairing or doing a full re-spray. Most homeowners discover the failure the same way: a bedroom ceiling that feels hot to the touch in July, an AC unit that won’t cycle off, or a musty smell drifting down from the attic hatch. We’ll tell you exactly what’s going on up there.

Call (903) 437-9164

Which Demilec Models This Applies To

We work with the two Demilec product lines most common in San Antonio attics: Sealection 500 (open-cell, half-pound foam) and Heatlok HFO Pro (closed-cell, two-pound foam). If your home was built or re-insulated in the last 10 to 15 years, it’s almost certainly one of these two. Look for a Demilec label on the foam itself, or check any paperwork left behind from the original install. No label? We can identify the foam type on site by density and cell structure, which matters more than the label anyway.

Here’s the compatibility gotcha most San Antonio homeowners don’t know: you cannot patch open-cell foam with closed-cell foam, or vice versa. The two expand differently, cure differently, and trap moisture differently. If a previous contractor “topped off” your Sealection 500 with a closed-cell product, that’s often the exact reason it’s failing now. We match the foam family first, then the specific Demilec product. As an independent San Antonio insulation company, we’re not affiliated with Demilec, but we install their products regularly and know how they behave in Texas attic conditions.

OEM vs. Aftermarket: What We Actually Recommend

For Demilec spray foam, there is no meaningful “aftermarket” equivalent. The two-part foam chemistry is proprietary, and generic substitutes don’t bond the same way. We stock genuine Demilec product on our trucks for both Sealection and Heatlok lines. For the ancillary parts that wear out around your attic insulation (baffles, sealing tape, can foam around penetrations), we carry quality equivalents where they match or exceed spec. The foam itself stays Demilec.

Signs Your Demilec Attic Insulation Is Failing

Here’s what San Antonio homeowners call us about most often:

• Foam pulling away from the roof deck. Demilec open-cell foam can detach over time, especially in attics that hit 130°F+ in summer. The foam loses adhesion and gaps open between the foam and the sheathing, creating direct thermal bridges.
• Cell structure breakdown at the top layer. Older Sealection installs sometimes show a crusty, oxidized surface layer that crumbles when touched. The foam below may be fine, but the damaged layer reduces R-value and should be scraped and re-sprayed.
• Discoloration or dark staining. This usually indicates moisture trapped against or inside the foam. Closed-cell Heatlok is a vapor barrier; if it was applied over damp decking, water gets locked in and mold follows.
• Hot ceilings in specific rooms. In San Antonio’s older neighborhoods, like the bungalows off McCullough Avenue, we see attic geometry that makes complete foam coverage difficult. If one bedroom ceiling consistently runs hotter, the foam in that bay likely has a gap or was never fully applied.
• Shrinkage around recessed fixtures or pipes. Foam shrinks slightly as it cures. Around unsealed penetrations, that shrinkage opens air channels. You’ll feel warm air entering the house in summer and smell whatever’s in the attic.

If more than one of these sounds familiar, you should have the attic inspected before the next San Antonio heat wave. The earlier we catch delamination, the less we have to remove and re-spray.

Replacement Cost & What’s Included

For San Antonio Demilec attic work, here’s what we tell people before they spend a dime with us:

What’s included in every quote: removal of failed foam where needed, surface prep, re-spray, and a second visit to confirm the foam cured correctly and reached its target R-value. What’s not included: surprises. We write your price down before any work starts, so you’ll know exactly what the job costs before we open the attic hatch. Every job falls under our 365-Day Done Right Promise. If the foam doesn’t perform, we make it right, no debate, no fine print.

DIY or Call Us?

You can safely check a few things yourself. From the attic hatch, take a look at the foam near the roofline. If you see gaps wide enough to slip a finger between foam and decking, or if the foam surface looks cracked like old paint, you’ve found the problem. That’s where safe self-inspection ends.

Spray foam remediation is not a DIY project. Removing failed Demilec foam requires cutting tools and creates dust you don’t want in your lungs. Re-spraying requires a two-part heated proportioner running at specific temperature and pressure; a $35,000 rig that trained crews operate wearing full PPE. We wear shoe covers from the front door to the attic hatch, lay drop cloths across your hallway, and use quiet equipment when children are sleeping. Call (903) 437-9164 and we’ll inspect the attic and give you the written number before anything gets touched.

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