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Tamko Home Additions & ADU: The San Francisco Owner’s Guide
Tamko home additions and ADU projects in San Francisco typically run $53,100 to $153,400 for a permitted, code-compliant build, and a full ADU construction starts at $106,200 and can reach $259,600 depending on site conditions. We carry and install Tamko roofing underlayments, weather barriers, and flashing systems on every addition and ADU we frame, and we can match an existing Tamko roof system on your primary home so the new structure ties in without a visible seam at the ridge or eave line. Most homeowners discover a Tamko-related failure the same way: a soft spot in the ceiling under a new addition, water staining at the transition where the addition roof meets the original structure, or underlayment that tore during rough-in and was never corrected before the finish roofing went down.
If you’re reading this because a Tamko roofing or underlayment product failed on a recent addition or ADU, you want two things: a straight answer about whether it’s a product defect or an installation problem, and a written price to make it right. We give both, in writing, before any work starts. That’s The Garrison Standard, and it’s been how Bradford Remodeling Co San Francisco has operated since day one.
Key Takeaways:
- Installed Tamko-related addition and ADU work in San Francisco ranges from $53,100 to $153,400, with full ADU construction starting at $106,200.
- We stock Tamko-compatible underlayment, flashing, and ventilation components on our trucks for most common San Francisco roof profiles.
- Every job gets a written price before work begins, and every completed project carries our 365-Day Done Right Promise in writing.
- Call (831) 610-5598 and a live person answers. Not a voicemail, not a callback queue.
Which Tamko Models This Applies To
Tamko makes a range of roofing products, but for home additions and ADUs in San Francisco, the ones we see most are the Tamko® TW™ Series underlayments, Tamko Awaplan™ self-adhered base and cap sheets for flat-roof sections, and their Heritage® shingle line for pitched roofs. If you have a flat-roof ADU, which is common in the Sunset and Richmond districts because of the marine layer and coastal wind, the critical material is usually the self-adhered base sheet and the flashing at the parapet wall. If you have a pitched addition, it’s the synthetic underlayment and the ice-and-water shield at the eave line and valleys.
Here’s the compatibility detail that catches people: Tamko’s Awaplan self-adhered sheets are not interchangeable with their TW synthetic underlayments. One is a peel-and-stick membrane for low-slope and flat roof sections, the other is a mechanically fastened synthetic underlayment for steep-slope roofs. We’ve seen additions in Noe Valley and Glen Park where a previous contractor used the wrong product because both come in similar rolls, and the failure shows up within the first two wet seasons. If you’re not sure what’s on your roof, we can pull a sample from the eave line and identify it in about ten minutes.
For homeowners deciding between OEM Tamko and a quality aftermarket equivalent: we install OEM Tamko products whenever the rest of your roof system is Tamko, because the manufacturer’s warranty on the roof assembly only stays intact when the components match. If your existing roof is another brand, we’ll spec a compatible underlayment or flashing from a manufacturer whose warranty doesn’t conflict. We don’t guess at this, and we won’t mix products that leave you holding a voided warranty, which is a real risk on additions that tie into an existing roof.
Styles & brands we work with
Signs Your Tamko Home Additions & ADU Is Failing
- Water staining at the transition between the addition roof and the original house. This is almost always a flashing failure where the new roof meets the old, not a shingle problem. In San Francisco, the fog-driven moisture in the Outer Sunset and Richmond makes this the first place water will find a gap.
- Bubbling or blisters in the underlayment on a flat-roof ADU. Trapped moisture between the deck and the self-adhered membrane expands when the sun hits it. Over time, the blisters crack, and water gets to the plywood deck underneath.
- Granule loss from Tamko Heritage shingles within the first five years. Some granule shed is normal, but heavy loss concentrated at the eaves or in valleys signals a ventilation or drainage problem, not just aging. In San Francisco’s damp microclimates, a poorly ventilated addition roof can shed granules at twice the normal rate.
- Soft spots or sagging in the ceiling below the addition roof. By the time you feel a soft spot, the plywood deck or the framing below it has been wet for a while. This is the symptom that usually pushes a repair from a few hundred dollars into the $4,000 to $12,000 range, depending on how much framing needs to come out.
- Peeling tape or looseness at the underlayment seams in the attic. If you can get into the attic space of the addition and the Tamko underlayment seams are lifting, the fastener schedule was wrong or the overlap was too short. Seam failure is the most common installation error we correct on additions that are less than five years old.
See the difference
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AfterReplacement Cost & What’s Included
If the issue is isolated to flashing, underlayment repair, or a section of failed Tamko roofing membrane on a small flat-roof ADU, you can expect a repair in the $4,720 to $15,340 range depending on how much framing needs replacement. If the failure is extensive and the roof deck has been compromised, or if the addition itself was improperly framed and waterproofed, you’re looking at a partial or full re-roof of the addition in the $9,440 to $23,600 range, and a worst-case rebuild of a failed addition runs from $53,100 on up.
Every quote we write in San Francisco includes the parts, the labor, the dump fees, and the written guarantee in one number. No line items that appear later, no “unforeseen conditions” surprises unless something is genuinely hidden inside the wall or deck, and if we find it, we photograph it, show you, and give you a written change order before we spend another dollar. Our 365-Day Done Right Promise means if the repair fails within the first year, we come back and fix it at no charge. We don’t send a different crew and we don’t re-quote it. It’s in writing, signed, in your hand at close-out.
Straight number, real scope, no surprises at close-out. That’s the whole job.
DIY or Call Us?
There are exactly two things a homeowner can safely check on a Tamko addition or ADU roof: visible flashing separation at the transition to the main house, and granule accumulation in the gutters. Both are diagnostic, not repairs, and neither requires you to leave the ground. The moment the fix involves a ladder, a roof surface, a knife, or a torch-down application, you should call a licensed contractor. Flat-roof membrane work on a San Francisco ADU is not a weekend project, and a bad torch application on a self-adhered system is how you get a roof fire, not a fixed roof.
If you’ve spotted a problem or you’re planning an addition or ADU and want a Tamko roof system spec’d correctly from the start, call (831) 610-5598. Ask for a written estimate. Curtis Lane and the crew at Bradford Remodeling Co San Francisco will schedule a site visit, measure the roof, check the existing Tamko system, and give you a line-item price you can take to the bank. Free estimate, no pressure, no countdown clock.
FAQs
A correctly installed Tamko Heritage shingle roof on a properly ventilated San Francisco addition typically lasts 20 to 30 years, while a flat-roof Awaplan system on an ADU in the fog belt realistically lasts 15 to 20 years before the membrane needs replacement. The marine layer in the Sunset and Richmond accelerates wear at the seams and flashing, so annual inspection of those areas matters more here than it does inland. Call (831) 610-5598 if you want us to check the condition of your existing Tamko roof before you plan a repair or an addition tie-in.
Yes, if the failure is caught early and limited to a seam or a single penetration point, we can repair the affected section with compatible Tamko materials and restore the waterproofing. If the underlayment has widespread seam lifting or the deck below is damaged, a section replacement is the honest fix, and we’ll show you the evidence before we write the change order. Call (831) 610-5598 for a written assessment.
A flashing repair or localized membrane repair on a flat-roof ADU in San Francisco is usually a one to two day job once we have the materials on site, and we stock common Tamko flashing and membrane products on our trucks. A full re-roof of a larger addition can take three to five days depending on weather and the condition of the deck. We’ll put the timeline in writing when we give you the price.
We stock Tamko TW synthetic underlayment, Awaplan self-adhered base and cap sheet material, and common flashing profiles in our San Francisco yard, so most repairs can start within a few days of your written approval. If your job requires a specific Tamko shingle color or a less common membrane specification, we order it direct from our supplier and confirm the lead time before we schedule the work. Call (831) 610-5598 and tell us what you need, and we’ll tell you if it’s on the truck or on order.
If your Tamko home addition or ADU roof is failing, or you’re planning a new build and want the roof system done right the first time, call Bradford Remodeling Co San Francisco at (831) 610-5598. We’ll give you a written price for the repair or the full project, a timeline in writing, and a signed 365-Day Done Right Promise before we pick up a tool. We’re an independent contractor in San Francisco, not affiliated with Tamko, and we’ve built our reputation on written scopes, straight numbers, and work that holds up through the foggiest winters this city can throw at it.
Written by Curtis Lane, Owner, Bradford Remodeling Co – San Francisco, CA at Bradford Remodeling Co San Francisco, serving San Francisco and nearby areas.
