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CertainTeed Home Additions & ADU: The San Antonio Owner’s Guide
A home addition or ADU built with CertainTeed materials in San Antonio typically runs $45,000 to $130,000 for a full project, depending on square footage, foundation work, and how much of the existing roofline changes. We install and service CertainTeed-compatible additions and ADUs throughout San Antonio, and most material assessments can be scheduled within a few business days. The failed part is rarely the framing or the sheathing itself: it’s usually the integration point where CertainTeed roofing, siding, or insulation meets the existing house, and that’s where a San Antonio summer shows its teeth first.
Most owners discover the failure through a ceiling stain that won’t dry, a utility bill that climbs for no obvious reason, or a door that suddenly sticks in a room that was square six months ago. These aren’t coincidence. They’re the house telling you where the connection failed.
Which CertainTeed Models This Applies To
CertainTeed doesn’t make “home addition kits” the way they make shingle lines. What they do make is a system of envelope products: Landmark and Grand Manor shingles, Cedar Impressions and Monogram siding, MemBrain vapor retarder, and CertaWrap weather-resistant barrier. A San Antonio addition built to last uses those materials in a specific sequence, and the compatibility gotcha is almost always at the transition: the flashing detail where new CertainTeed roofing ties into old roof deck, or the siding-to-foundation joint where CertaWrap gets terminated incorrectly.
On the OEM-versus-aftermarket question for CertainTeed specifically: we use CertainTeed’s own flashing, starter strips, and sealants on warranty-covered envelope work, because mixing aftermarket components at the transition points voids the CertainTeed material warranty and, more importantly, creates the exact seam where water gets in. For interior framing, insulation, and drywall, quality aftermarket equivalents are fine and often a smarter spend. The right part is the one that matches the system it’s joining. We check product labels, fastener patterns, and existing penetrations before we quote anything.
Styles & brands we work with
Signs Your CertainTeed Home Additions & ADU Is Failing
- Ceiling stains or bubbling paint at the old-house-to-new-house seam. This is the classic San Antonio failure: the roof tie-in wasn’t flashed for our rain bursts, and water is traveling along the truss line. It’ll show up months after the last big storm, not during it.
- Utility bills that climb 20% or more year-over-year with no change in usage. A failed CertaWrap or compressed CertainTeed insulation at the addition’s exterior walls lets conditioned air escape, and in a San Antonio August, that’s money leaving through the wall cavity every hour.
- Doors or windows in the new space that stick seasonally. CertainTeed systems tolerate moisture, but they don’t tolerate standing moisture. If the vapor barrier was installed backward or sealed poorly, the framing swells and shrinks with every humidity swing. San Antonio’s humidity swings are constant.
- Visible daylight or drafts at the eave where the addition roof meets the original roofline. That’s a failed drip edge or missing closure strip. It’s also an open invitation for squirrels, bats, and every lizard in Bexar County.
- Efflorescence or white chalky residue on the slab at the addition’s perimeter. That’s moisture wicking up through the foundation, which means the CertaWrap termination at the sill was done backward or left exposed. Over time, that same pathway rots the bottom plate.
See the difference
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After
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AfterReplacement Cost & What’s Included
In San Antonio, a full CertainTeed-based home addition with proper envelope integration runs $45,000 to $130,000. Attached ADUs with separate entrances, kitchenettes, and dedicated utilities land at the higher end: $90,000 to $220,000. Garage conversions fall between $30,000 and $80,000 depending on whether you’re adding a bathroom and how much of the slab needs plumbing.
What drives the range is square footage, foundation type (pier-and-beam runs less than slab-on-grade in most San Antonio lots), and how much of the existing roofline has to be reframed to tie in cleanly. Every quote includes the CertainTeed envelope materials, framing lumber, insulation, drywall, paint, and the labor to make the transition details right, not just pretty. We put the price in writing before any work starts, on every project, every time. Isaac Pruett got tired of watching homeowners discover “allowances” on invoices twenty years ago. Our written price is the price. And the work is covered by our 365-Day Done Right Promise: if it’s not right within a year of completion, we make it right at no cost to you.
DIY or Call Us?
You can safely check the obvious: walk the addition perimeter after a rain, look up at the eave transitions, run your hand along interior drywall seams for softness. What you shouldn’t do is pull shingles, cut into CertaWrap, or reframe a roof-to-wall connection yourself. The danger isn’t just water damage; it’s structural. A bad tie-in can put lateral load on a wall that wasn’t engineered for it, and a roof that starts moving in a San Antonio wind event is a hazard to everyone inside.
The DIY attempt that goes wrong is always more expensive than the professional fix done once. If you suspect your CertainTeed addition or ADU envelope has failed, call (254) 269-5071 and we’ll send someone who knows exactly what to look for. Know who’s coming, know what it costs, know it’s covered – that’s the whole job before the job starts.
FAQs
A properly built CertainTeed-enveloped addition in San Antonio should last 30 to 50 years on the exterior, with interior finishes lasting 20 to 30 years before significant refreshing. The wildcard in our climate is the transition details: a poorly flashed roof tie-in can fail in as little as three seasons. Call (254) 269-5071 if your addition is under ten years old and showing water or draft symptoms – that’s a workmanship failure, not age.
Yes, in most cases. If the framing is sound and the problem is localized to flashing, sealant, or weather barrier at the transition points, we repair rather than rebuild. That typically runs a few thousand dollars, not tens of thousands. The key is catching it before the bottom plate rots or the trusses show water damage. Call (254) 269-5071 for an assessment – estimates are free.
A standard addition takes 8 to 16 weeks from permit to final walkthrough. An attached ADU with plumbing and a kitchenette runs 16 to 24 weeks. Permitting through the City of San Antonio and any historic district overlays adds time, but we pull the permits and schedule inspections as part of the written price. Call (254) 269-5071 for an exact timeline on your specific lot.
We stock common CertainTeed flashing, sealants, starter strips, and CertaWrap on our trucks for repair work. Full shingle or siding orders for a new addition are sourced from our San Antonio supplier partners to match your existing color and product line exactly. We also work with KraftMaid, Cambria, and Silestone for the interior finishes that complete an addition. Call (254) 269-5071 and we’ll confirm material availability before you commit to a start date.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Antonio at Mason Remodeling Co San Antonio, serving San Antonio and nearby areas.
