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Tamko Underlayment & Deck Repair: The San Antonio Owner’s Guide
If your Tamko roof underlayment has torn, wrinkled, or started peeling back from the deck, we stock the replacement materials and can usually complete the repair in a single visit. Most Tamko underlayment and deck repairs in San Antonio run $450 – $1,200 depending on how many squares need attention and whether the deck itself has rot or water damage. The way most homeowners find out is unglamorous: a leak stain on the ceiling after a hard Hill Country storm, or a roofer (sometimes us) lifting a shingle during an unrelated repair and finding the synthetic underlayment has degraded underneath.
This page covers what fails, what it costs, and whether you should climb up there yourself. Short version on that last one: probably not, and we’ll explain why without lecturing you about it.
Which Tamko Models This Applies To
Tamko makes two underlayment lines you’ll find on San Antonio roofs: TW Metal and Tile Underlayment and the newer TW-60 Synthetic Underlayment. The TW-60 is the one we see most often on residential steep-slope shingle roofs installed in the last 8 to 10 years. It’s a 60-mil woven synthetic that replaced the old #15 felt in Tamko’s recommended system. The Metal and Tile version is thinner, 40-mil, and designed for use under standing seam metal and concrete tile, where it sees different temperature and puncture conditions.
Here’s the compatibility gotcha most owners miss: Tamko’s warranty documentation only covers the underlayment when it’s installed as part of a full Tamko system with Tamko shingles and Tamko fasteners. If your roof was installed by a contractor who used Tamko underlayment with a different shingle brand, the product itself is still fine to repair with Tamko material, but the manufacturer warranty may not apply to the original installation. We work with this every week, and we’ll tell you plainly what’s covered and what’s not before we touch anything. We’re an independent service provider, not affiliated with Tamko, so our interest is in fixing your roof correctly, not defending a warranty claim.
If you’re unsure which underlayment is on your roof, the easiest check is to look for the printed Tamko logo on the material surface. It repeats every few feet on TW-60. If the underlayment is too degraded to read, we can identify it by thickness and weave pattern once we expose a section. We also stock GAF, Owens Corning, and CertainTeed underlayment equivalents, but for a Tamko roof we default to Tamko material unless you specifically ask for something else.
Styles & brands we work with





Signs Your Tamko Underlayment & Deck Repair Is Failing
- Leak stains on ceilings or exterior walls after moderate rain. Underlayment is the roof’s second line of defense after shingles. When it fails, water that gets past a lifted or damaged shingle has a direct path to the deck. In San Antonio, we see this most often after the first big storm following a dry stretch, because shingles contract and lift slightly, exposing whatever is underneath.
- Visible wrinkles, rips, or flapping material at the eaves or rakes. TW-60 is a wrinkle-resistant product, but it’s not wrinkle-proof. Improper installation, extreme heat cycling, or roof movement can cause it to bunch and separate at the edges. If you can see it from the ground, it’s already compromised.
- Soft or spongy spots on the deck when walking the roof. Water that sits against plywood or OSB decking for months rots it. By the time the deck feels soft, the underlayment above it has been failing for a long time. This is a bigger repair than just swapping underlayment.
- Granule buildup in gutters alongside dark staining on the deck. This points to shingle breakdown above the underlayment. The underlayment may still be holding, but once the shingles go, it’s only a matter of time. We address both layers in one visit to avoid a second trip.
- Musty odor in the attic after rain. This is a slow leak, not a gusher. Water is getting through both the shingle layer and the underlayment, saturating the deck, and the deck is holding moisture. San Antonio’s heat makes this worse: trapped moisture plus 100-degree attic temperatures accelerates deck rot fast.
See the difference
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After
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AfterReplacement Cost & What’s Included
In San Antonio, a localized Tamko underlayment repair with deck spot-replacement typically runs $450 – $800 for a small area under 2 squares (200 square feet). A full neighborhood-wide underlayment and deck evaluation with repairs across multiple problem areas runs $800 – $1,200. If the deck itself has significant rot requiring whole-sheet replacement, that adds material and labor and can push the job to $1,500 – $2,500 depending on sheet count and accessibility.
Every quote we give is a written, line-item price before any work starts. The number on the estimate is the number on the invoice. No change orders, no “we found additional damage” surprises unless you approve it in writing first. That’s the Relay Visibility Guarantee, and it applies to every repair we do, including Tamko underlayment and deck work. The repair itself is covered for 365 days under our Done Right Promise. If it fails within a year, we come back and fix it at no charge.
DIY or Call Us?
You can safely check your attic for water staining, daylight coming through the deck, or damp insulation after a storm. What you shouldn’t do is remove shingles to inspect underlayment on a two-story San Antonio roof without a fall-protection setup. Roof work is dangerous in ideal conditions, and San Antonio roofs get slick with dew and algae. We’ve also seen DIY repairs where homeowners used roofing cement to “patch” torn underlayment, which just traps water against the deck and rots it faster.
If you’re comfortable on a ladder and just want to inspect the eaves and rake edges visually, that’s reasonable. Anything beyond that, call us. We’ll send a background-checked, uniformed technician with a documented arrival time, and you’ll get photos of what we found before we quote anything.
Call (361) 209-8857 to schedule a free estimate. Dylan Pace and our team will walk you through exactly what’s on your roof and what it costs to make it right.
FAQs
TW-60 synthetic underlayment is rated for long-term exposure and should last 25 to 30 years under proper installation conditions. In San Antonio’s heat and UV cycles, the practical lifespan on a steep-slope roof is closer to 15 to 20 years before we’d want to evaluate whether it’s still doing its job. Factors like attic ventilation and whether the original installer used the full Tamko system play a role. If your roof is over 15 years old and the underlayment has never been inspected, call (361) 209-8857 and we’ll take a look.
Small tears at the edges can sometimes be repaired by re-securing and sealing the affected area, but torn field underlayment under the shingles almost always requires replacement of the damaged section. Patching tears from above without lifting shingles doesn’t address the underlying issue and traps water. We’ll give you an honest recommendation after we see the actual damage, and every repair includes a written price before we start.
Most localized underlayment repairs with minor deck work take one full day, sometimes two if we’re replacing multiple deck sheets and waiting for the surface to dry. We’ll give you a clear timeline on the estimate and stick to it. Call (361) 209-8857 for a free estimate and we can usually get out within a few days, depending on weather and schedule.
Yes, we keep TW-60 and the TW Metal and Tile underlayment in stock on our trucks, along with the fasteners and sealants Tamko recommends for their systems. That means most repairs start on the first visit without waiting on a material order. If you have a rarer Tamko product on your roof, we’ll source it and give you a written timeline before any work begins.
Every promise we make goes in writing, because a handshake doesn’t keep water out.
Written by Dylan Pace, Owner, Crestview Roofing Co San Antonio at Crestview Roofing Co San Antonio, serving San Antonio and nearby areas.