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CertainTeed Home Additions & ADU: The San Antonio Owner’s Guide
If you’re planning a home addition or ADU in San Antonio with CertainTeed materials in the build, our crews at Sawyer Remodel San Antonio handle it end to end. The cost for a full home addition in San Antonio typically lands between $45,000 and $130,000, while an ADU construction runs $90,000 to $220,000 depending on square footage, foundation work, and finishes. Most owners find us when their existing addition or ADU starts showing real problems: cracked drywall at the seam where old meets new, a roof that leaks at the transition line, or a mini-split that can’t keep the added space comfortable in an August heat wave. Those symptoms usually point to the same root cause: the original build cut corners where the new structure ties into the house.
Key Takeaways
- Cost range for San Antonio home additions: $45,000 – $130,000 installed, including CertainTeed materials where specified.
- ADU construction: $90,000 – $220,000 depending on foundation type, plumbing runs, and finish level.
- We install and source CertainTeed roofing, siding, and insulation products as part of full addition and ADU builds, not as retrofit patches.
- The written price you approve is the price you pay. No change orders unless you ask for a change.
- SAFETY NOTE: If your existing addition has failing roof decking or structural tie-in issues, call us. Don’t stand on a ladder near a compromised transition point.
Styles & brands we work with
Which CertainTeed Models This Applies To
CertainTeed doesn’t manufacture “home additions” as a kit. What they make is the material layer that makes an addition or ADU in San Antonio last: Landmark and XT 30 shingles for the roof, CertaWrap or MemBrain for the weather barrier, and their full line of insulation batts and boards. When we build or repair an addition, the CertainTeed spec matters because the products are tied to specific performance ratings under Texas heat and hail conditions.
Here’s the compatibility gotcha most owners don’t know: CertainTeed Landmark shingles are rated for a specific slope and underlayment combo. If your addition’s roof runs at a pitch under 2:12, standard Landmark won’t perform to warranty spec, and you need a low-slope system instead. We check this before any material gets ordered. Same goes for CertaWrap: it’s not interchangeable with any housewrap if you’re matching an existing wall assembly. We pull the existing product data from the home’s records or identify it on site before we write the quote.
On the ADU side, CertainTeed’s Sustainable Insulation line shows up more often now because San Antonio’s updated energy code for accessory dwellings demands specific R-values in the wall and ceiling cavities. The product label matters: R-13 vs R-19 vs R-21 is not a preference, it’s a code requirement. We quote the right one the first time and note the spec on your written estimate.
Sawyer Remodel San Antonio is an independent contractor. We’re not affiliated with CertainTeed, which means we can install their products without a brand rep steering your material choices. We stock the most common CertainTeed items for addition and ADU jobs and order the rest direct from local supply houses, usually same week.
Signs Your CertainTeed Home Additions & ADU Is Failing
- Water stains at the seam where the addition roof meets the original house. This is the most common failure point on San Antonio additions, and it almost always traces to a bad flashing detail, not the shingles. The original builder flashed the transition wrong or used caulk instead of metal, and ten years of Texas rain found the gap.
- Cracks running vertically from the corner of a new doorway or window in the addition. That’s differential settling. The new foundation sinks at a different rate than the original slab, and the wall framing follows it. If the crack is wider than a dime, you need a structural look before it affects the roof line.
- The ADU’s interior walls get hot to the touch by 3 p.m. in July. That means the insulation was either installed with gaps or is the wrong R-value for a San Antonio summer. CertainTeed insulation performs fine when it’s spec’d and installed right. When it’s not, you feel it on the west-facing wall first.
- You hear wind whistling through the electrical outlets on an exterior wall of the addition. Air is getting past the weather barrier. CertaWrap only works if it’s lapped and taped correctly at every penetration. A whistling outlet means someone rushed that step or skipped it entirely.
- Drywall tape keeps separating at the ceiling line where the addition ties to the main house. This is expansion and contraction working on a joint that was never properly backed. It’s a cosmetic symptom until the crack opens wide enough to let conditioned air escape, then it’s an energy bill problem.
See the difference
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After
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AfterReplacement Cost & What’s Included
Let’s talk straight numbers for San Antonio. A full home addition runs $45,000 to $130,000 depending on whether you’re adding a single bedroom or a master suite with a bathroom and walk-in closet. An ADU from slab to finished space lands between $90,000 and $220,000. That’s the installed price range, not a materials-only figure.
What drives the spread: foundation type (slab-on-grade vs pier and beam), plumbing rough-in distance from the main line, electrical panel capacity, the CertainTeed product line you select, and interior finish level. A garage conversion runs lower, $30,000 to $80,000, because the shell already exists and you’re not pouring new foundation or framing exterior walls from nothing.
Every quote we write includes the materials, labor, permits, dump fees, and the written warranty on our work. The price on your invoice is the price you approved before we started. If a change does come up mid-project, it’s a written change order you sign off on. That’s the Relay Visibility Guarantee, and it applies to every addition and ADU we build in San Antonio.
DIY or Call Us?
For home additions and ADUs, DIY is not the play. This is framing, foundation, roofing, electrical, and plumbing all at once, and the failure points on a San Antonio addition are structural, not cosmetic. Standing on a ladder near a failing roof transition with a caulk gun doesn’t fix the flashing detail underneath. It just delays the leak until the next storm and puts you in the ER if the ladder slips.
What you can safely do: document the symptoms. Take photos of the water stains, the cracks, the hot walls. Check your energy bills against the same month last year. That gives us a starting point before we even show up. But the repair itself, especially anything involving roof structure, load-bearing walls, or electrical tie-ins, is trained professional territory. Luca Romano has spent years working on San Antonio homes, from gut-and-rebuild kitchens in Alamo Heights to full ADU builds across the metro, and we still walk every job ourselves before we hand it back.
If your addition or ADU is failing, call us at (432) 547-6806. The estimate is free and the price is in writing before any work starts.
FAQs
CertainTeed Landmark shingles typically last 20 to 30 years in the San Antonio climate, but that lifespan drops fast if the original install used the wrong underlayment or skipped proper ventilation. Insulation products last indefinitely if they stay dry; a failed weather barrier shortens that to about a decade. Call (432) 547-6806 if you’re seeing the warning signs, and we’ll tell you what’s actually still good.
Most of the time, a failing addition can be repaired without tearing everything down. A bad flashing detail, a cracked seam, or under-spec insulation is fixable. Total rebuilds come into play when the foundation has moved significantly or the roof framing has rotted through at the tie-in. We’ll tell you honestly which one you have after the first walkthrough, before any money changes hands.
A single-room addition typically runs 8 to 14 weeks from permit to final walkthrough. An ADU from empty spot to finished living space runs 4 to 8 months depending on utility runs and weather. We give you a schedule with live arrival times and photo updates throughout, so you’re never wondering where the crew is. Call (432) 547-6806 for a project-specific timeline.
We stock the most common CertainTeed roofing and insulation products on our trucks and at our San Antonio supply accounts. Specialty CertainTeed items, like specific shingle colors or high-R-value board insulation, we order direct and usually have them in hand within a week. You never need to source materials yourself. We handle it and put every material on your written quote.
If you’re planning an addition or ADU in San Antonio, or you’ve got an existing one that’s showing problems, call us at (432) 547-6806 to schedule your free estimate. We’ll give you a written price before any work starts, and we’ll stand behind it.
Written by Luca Romano, Owner, Sawyer Remodel San Antonio at Sawyer Remodel San Antonio, serving San Antonio and nearby areas.
