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Flat & low-slopeFree roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Tamko Underlayment & Deck Repair: The Austin Owner’s Guide
Tamko underlayment and deck repair in Austin typically runs $400 – $1,800 installed, depending on how much decking has rotted and how many squares of underlayment need replacing. We stock Tamko-compatible underlayment on our trucks and can usually complete smaller repairs in a single visit. Most Austin homeowners discover the problem one of two ways: a leak shows up on the ceiling after a hard spring storm, or a roofer poking around for an unrelated issue points out soft decking and lifted felt. By the time you see water inside, the underlayment has usually been compromised for a while. Texas sun breaks down synthetic underlayment faster than people expect, and once the decking gets wet, rot spreads quick. We walk every inspection with you, show you photos of what we found, and hand you a written price before any work starts.

Which Tamko Models This Applies To
Tamko makes two underlayment families we work with most: the TW Metal and Tile series and the synthetic Apex line. The TW underlayments come in roll sizes of roughly 36″ × 144′ and are self-adhered, which matters because Austin’s heat softens the adhesive over time and can create bonding failures along laps. Apex comes in both 250 and 500 synthetic weights, and we see the 250 used most on steep residential pitches around Zilker, Tarrytown, and Mueller. Here’s the compatibility gotcha: Tamko warrants its shingles only when the underlayment meets their published specs, so swapping in a generic #15 felt on a Tamko roof can quietly void your shingle warranty. That’s the OEM-vs-aftermarket decision in a nutshell. We install Tamko-compatible underlayment when your roof carries Tamko shingles, and we’ll tell you plainly when a quality aftermarket synthetic like certain Owens Corning or GAF deck armor equivalents does the job for less. If you have the original shingle wrapper or an invoice, bring it out. We match by brand and series, not by guesswork.
Styles & brands we work with






Signs Your Tamko Underlayment & Deck Repair Is Failing
- Water stains on ceilings or walls after rain. This means water has already passed through the shingles, the underlayment, and the decking. By the time you see the stain, the deck in that spot is usually soft or actively rotting.
- Granules in gutters and downspouts. Austin’s summer heat cooks the adhesive that holds shingle granules. When Tamko shingles shed granules, the underlayment underneath gets direct UV and impact exposure it was never meant to take for long.
- Spongy or bouncing deck when walked on. If your roofer or inspector steps on a spot and it gives, that’s decking rot. Underlayment failure let water sit against the OSB or plywood, and now the structural layer is compromised.
- Visible lifting or wrinkling at underlayment seams. On exposed rakes and eaves you can sometimes see the underlayment curling. Austin’s freeze-thaw cycles in winter and 100-degree summers break the bond along laps faster than Tamko’s rated service life.
- Shingle distortion or ‘picture framing.’ When underlayment fails unevenly, shingles won’t lie flat. You’ll see outlines of the decking panels showing through the shingle lines. That’s moisture expansion underneath and it will not self-correct.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
For Austin homeowners, the installed price usually breaks like this:
- Spot deck repair (one or two sheets of OSB replaced): $400 – $800
- Full underlayment replacement on a standard 25 – 30 square roof: $1,200 – $1,800
- Combined deck and underlayment repair with shingle re-installation: $1,800 – $3,400
The range comes down to how much decking you’ve lost, whether we’re working around existing shingles or doing a full tear-off, and the pitch of your roof. A steep roof takes longer and costs more to work safely. Every price we give is written before we start, and it includes labor, materials, and haul-off. You will not get a change-order phone call from us. Every repair carries our written 365-Day Done Right Promise: if it’s not right within a year, we make it right. That includes a free second visit if the repair fails.
DIY or Call Us?
You can safely inspect from the ground: look for lifted shingles, exposed underlayment at the eaves, or granule streaks in your gutters after a storm. That’s worth doing once a year in Austin, especially after hail season. What you should not do is pull up shingles to peek at the decking. Walking a pitched roof without proper tie-off is genuinely dangerous, and lifting shingles without knowing how to reseal them creates the same water intrusion you were looking for. Underlayment and deck work also means handling utility knives, roofing nails, and sometimes a fall arrest harness. If you find soft decking, call us. We’ll send a background-checked, photo-badged technician whose name and photo you’ll have before they arrive. Grant Whitlock has spent years on Austin roofs, including a stretch in Zilker where summer hail kept him busier than he’d have liked, and he’ll tell you exactly what’s worth fixing now and what can wait. Your roof shouldn’t be something you worry about, that’s what we’re here for.
FAQs
Tamko synthetic underlayment is rated for the life of the shingle, but Austin’s heat, hail, and UV exposure realistically push most underlayment into the 15 – 20 year range before we start seeing seam failures and brittleness. A roof that’s vented poorly will shorten that. Our inspections include reading the underlayment’s condition, not just the shingles, because that’s what actually protects your decking.
Yes, if the failure is localized to a small section and the decking underneath is still solid. We can cut back the damaged underlayment, inspect the deck, install new Tamko-compatible underlayment with proper lap and seal, and re-install the shingles. If the damage is widespread or the underlayment has delaminated across large sections, patching becomes costlier than a full replacement. Call (361) 202-8874 and we’ll give you an honest answer based on what we actually see.
Most spot repairs take one working day. A full underlayment replacement on an average Austin home takes two to three days depending on roof pitch and how much decking needs replacing. We’ll give you a written timeline with the written price before work starts.
We stock Tamko-compatible underlayment and OSB decking on our trucks, along with compatible underlayment and deck products for GAF, Owens Corning, and CertainTeed roofs. For unusual Tamko series or older products, we source from local supply houses in Austin and can typically have them the same or next day. If your roof has a discontinued Tamko product on it, we’ll tell you that before quoting so there are no surprises.
If you’ve got a leaking roof, soft decking, or a Tamko roof that’s showing its age, call (361) 202-8874 for a free estimate. We answer live, 24/7, and we’ll set up a time to inspect your roof, show you exactly what we found, and hand you a written price with no obligation.
Written by Grant Whitlock, Owner, Mercer Roofing Co Austin at Mercer Roofing Co Austin, serving Austin and nearby areas.