Tamko Underlayment & Deck Repair Nationwide

Tamko Underlayment & Deck Repair: The Los Angeles Owner’s Guide

Tamko underlayment and deck repair in Los Angeles typically runs $450 – $1,400 installed, depending on how much decking has rotted and what underlayment your roof needs. We stock Tamko-compatible underlayment on our trucks and can usually complete the repair the same day we diagnose it. You’ll usually discover the problem after a leak shows up on your ceiling, or when a roofer doing a shingle replacement pulls back the old layer and finds the plywood underneath has turned to sponge.

Call (743) 200-8347

In Los Angeles, what we see most often is not storm damage. It’s the slow, quiet damage from years of sun baking the underlayment until it gets brittle, paired with moisture that found its way in through a cracked tile or a lifted shingle. The underlayment is the waterproof layer between your decking and your shingles or tile. The decking is the structural wood underneath. When one fails, the other follows. Tamko makes the underlayment we install most often on re-decks across the San Fernando Valley, the Westside, and down through South LA.

Here’s what every Los Angeles homeowner with a Tamko roof should know about underlayment and deck repair before they call anyone.

Which Tamko Models This Applies To

Tamko currently manufactures underlayment products that go under their Heritage and Elite shingle lines, plus their TW-60 and TW-100 synthetic underlayments that work across multiple roof types. If your home has Tamko shingles, you likely have either Tamko’s felt-based underlayment (older installations) or their synthetic line (newer work, roughly the last 8 to 10 years). The quickest way to identify what you have: check any leftover rolls in your garage or attic, or look for the Tamko brand stamp on the exposed underlayment in your attic rafters.

The OEM decision matters here. Tamko’s synthetic underlayment has a slip-resistant coating that their felt does not. If you’re doing a partial re-deck, matching the remaining underlayment type matters for seam integrity. Generic aftermarket synthetic underlayment can work, but on Los Angeles roofs with low slope sections, the Tamko spec calls for a specific overlap and fastener pattern tied to their warranty. We carry both the OEM Tamko products and quality equivalents like Owens Corning and CertainTeed underlayments for when a full match is not necessary or the homeowner wants to compare options. We’re an independent service provider, not affiliated with Tamko, so we can give you a straight answer about whether the OEM premium is worth it for your specific roof.

Signs Your Tamko Underlayment & Deck Repair Is Failing

• Water staining on ceilings or walls, especially after rain. This is the most common first sign. It means water has breached the shingles and the underlayment is no longer stopping it. By the time you see the stain, the decking underneath is almost always involved.
• Soft spots or sagging visible from the attic. If you can safely get into your attic, look up at the underside of the decking. Dark streaks, white powdery residue, or wood that gives when you press it means the decking has absorbed water and is losing structural integrity.
• Granules from shingles collecting in gutters. Tamko shingles shed granules as they age. When that protective layer thins, the mat underneath degrades faster, which in turn exposes the underlayment to more UV and moisture than it was designed to handle.
• Peeling paint on exterior walls below the roof line. This often gets blamed on house paint, but what it actually means is water is running down the roof, getting under the underlayment at the eaves, and wicking into the fascia and wall sheathing.
• Curling or lifting shingles at the edges. Los Angeles heat causes Tamko shingles to expand and contract daily. Over years, this breaks the seal strip. Once shingles lift, the underlayment gets direct sun exposure and degrades faster than it would under a properly sealed shingle.

Replacement Cost & What’s Included

For a Los Angeles home with a typical roof section, here’s what installed repair pricing looks like right now:

• Underlayment replacement only (no deck damage): $450 – $900 for a standard roof section, including tear-off of the old felt or synthetic, new Tamko underlayment, and re-fastening of existing shingles or tiles where possible.
• Deck repair (partial, 1 – 3 sheets of plywood): $350 – $700 added on top of underlayment work. The range depends on whether we’re replacing 4×8 sheets of OSB or plywood, and how much structural framing needs attention underneath.
• Full re-deck and underlayment (entire roof): $1,800 – $4,200 for a typical Los Angeles single-story home, labor and materials included. This is the scenario where the decking has failed in more than half the roof area and piecemeal patching would be throwing money away.

Every quote we give includes the tear-off, disposal, materials, labor, and a written guarantee on the repair for 365 days. The written price you approve is the price you pay. No change orders, no “we found more damage and it’ll cost extra” surprises. If the repair fails within a year, we come back and fix it at no charge. That’s the 365-Day Done Right Promise, and it’s written on every invoice.

DIY or Call Us?

There are two things a homeowner can safely do here. One: inspect your attic with a flashlight and look at the underside of your decking. Two: clear your gutters so you can see if granules are accumulating. That’s where it should stop. Working on a roof in Los Angeles involves heights, sun-slicked surfaces, and the real possibility of stepping through a section of decking that looks fine from above but has rotted from underneath. We’ve seen homeowners put a foot through their ceiling because the decking was holding up shingles but not body weight.

The underlayment itself is not a high-tension danger like a garage spring, but the work environment is. Climbing a ladder with a 40-pound roll of synthetic underlayment, walking on a slope, and properly fastening seams so water never finds a gap is not weekend work. If you’ve spotted the signs and want a real diagnosis, call us at (743) 200-8347. We’ll send you the name and photo of your technician before they arrive, and they’ll show a photo ID badge at your door. You’ll know exactly who’s walking up your driveway.

FAQs

Get a Straight Answer About Your Tamko Roof

If you suspect your underlayment or decking is failing, don’t wait for the next rain to confirm it. Call Mercer Roofing at (743) 200-8347. We’ll send a technician to your Los Angeles home who arrives in uniform, shows a photo ID at the door, and gives you a written price before any work starts. No pressure, no fear-selling, just an honest assessment of what’s happening above your head. Grant Whitlock started this company because Los Angeles homeowners deserve a roofer they can feel safe opening the door to. That’s still the standard on every job we run.

Written by Grant Whitlock, Owner, Mercer Roofing at Mercer Roofing, serving Los Angeles and nearby areas.