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Tamko Home Additions & ADU: The San Francisco Owner’s Guide
Tamko home addition and ADU roofing, waterproofing, and underlayment materials fail differently in San Francisco than they do almost anywhere else in the country. Fog-driven moisture, salt air in the Sunset and Richmond, and decades of deferred maintenance on older homes mean a Tamko system that should last 30 years can show real trouble in 15. We regularly match failed Tamko shingles, underlayment, and flashing to the right replacement before the damage spreads into framing. Installed Tamko home addition and ADU work in San Francisco typically runs $53,100 – $153,400 depending on scope, roofline complexity, and whether we’re repairing the existing system or rebuilding it from the deck up.
Most homeowners discover the problem the way the weather reveals it: a water stain blooms on the ceiling of a new ADU, or the addition’s shingles start lifting at the eaves after a winter of repeated wet-dry cycles. Sometimes it’s quieter than that – a musty smell in the upstairs closet, or granules collecting in the gutter after every rain. By the time you see the stain, the part has usually been failing for a season or two.
Here’s what our crews see in San Francisco week after week, what to check before you call, and what honest Tamko replacement work should cost.
Which Tamko Models This Applies To
Tamko builds roofing and waterproofing products across several lines, and the part that fits one San Francisco addition won’t necessarily fit another. The main lines we work with are Tamko Heritage shingles (a dimensional asphalt shingle with a 30-year limited warranty), Tamko Titan XT (a heavier, high-wind shingle rated for coastal exposure), and Tamko’s MetalWorks steel roofing. For ADUs and additions specifically, the underlayment matters as much as the surface – Tamko’s TW and Moisture Guard lines are what keep San Francisco fog from turning a small roof into a big repair.
The fastest way to identify what you have is to check the roof permit paperwork from when the addition was built. No paperwork? Look for the shingle bundle label if any spares are left in a garage or crawl space. If there’s nothing, measure the shingle exposure – Heritage runs a standard 5-inch exposure, while Titan XT runs a 5-5/8-inch exposure. That measurement alone tells us most of what we need to know before we climb a ladder.
One compatibility gotcha we run into constantly: Tamko changed its shingle adhesive strip formulation about eight years ago. Older Tamko shingles and newer Tamko shingles don’t always seal to each other reliably in San Francisco’s temperature swings. That means a patch job on a 2012-era addition can look fine in August and leak by February. We tell homeowners this before they spend money, not after.
As for OEM versus aftermarket: for Tamko specifically, we recommend OEM shingles and underlayment because the manufacturer warranty only holds when the whole system is Tamko. Mixing brands works mechanically in some cases, but you lose the warranty chain. Given that San Francisco sees two or three severe wind events a year along the west slope, keeping the warranty intact is worth the slight premium.
We also stock and install compatible materials from KraftMaid, Cambria, and Silestone when the ADU project includes cabinetry or countertop work alongside the roof. The roof gets the attention first – everything below it depends on that.
Styles & brands we work with
Signs Your Tamko Home Additions & ADU Is Failing
- Water staining at the ceiling-to-wall corner of the addition or ADU. This is the classic sign of failed step flashing where the addition roof meets the main house wall. In older San Francisco homes, the flashing was often nailed into the siding rather than stepped correctly, and decades of thermal movement eventually open a seam.
- Shingle granules filling gutters after every rain. Some granule loss is normal for asphalt shingles after year ten. But if the gutter fills with granules every season and the shingle surface looks bald or shiny, the fiberglass mat is exposed to UV and the shingle is losing its waterproofing faster than it can shed water.
- Buckling or lifting at shingle edges after a wet winter. San Francisco’s dry summers and wet winters put asphalt shingles through an aggressive expansion-and-contraction cycle. When the decking underneath was installed with a gap (common in additions built before current code), the shingles can’t move freely and they start to lift at the seams.
- Stains or mold in the attic or crawl space directly under the ADU roof. This signals underlayment failure rather than shingle failure. Tamko’s underlayment is tough, but it doesn’t last forever under San Francisco’s fog belt. When the underlayment goes, moisture moves through the sheathing even when the shingles look fine from the street.
- Daylight visible through the ridge vent or gaps at the roof-wall junction. If you can see light from inside the attic, water has a path in. We see this often on San Francisco additions where the original roof cut was made too aggressively, or the ridge cap was reused instead of replaced during a past repair.
See the difference
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After
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AfterReplacement Cost & What’s Included
Tamko home addition and ADU work in San Francisco runs from $53,100 for a straightforward repair-and-reseal job on a smaller addition to $153,400 for a full rebuild with structural correction, new Tamko shingles, new underlayment, and new flashing details. That range covers everything from a single failed plane on a 400-square-foot addition to a complete re-roof on a 1,200-square-foot two-story ADU with dormer work.
What drives the price up in San Francisco specifically: roof access. A Sunset District ADU with a flat-back roofline and easy ladder access costs less than a Noe Valley addition where the roof is steep, three stories up, and the neighbor’s fence sits four feet from the drip edge. We factor scaffolding, debris removal (which includes our shoe covers and drop cloths through the house), permit fees, and the written line-item quote you’ll see before anything starts.
Every Tamko replacement job includes the full Cedarwell Care Promise: a written price before any work starts, drop cloths and shoe covers on every trip through the house, quiet tools during nap and school hours where possible, and a photo of the clean-up before the crew leaves. And the 365-Day Done Right Promise stands behind the whole thing – if it’s not done right, we make it right.
DIY or Call Us?
You can safely do the detective work from the ground: check your gutters for granules, look up at the eaves for lifting shingles, and check the ceiling inside the ADU for stains. That information helps us quote the job accurately before we arrive. What we recommend against is walking an addition roof in San Francisco without fall protection and the right equipment. A steep pitch over a wet shingle roof is how experienced roofers get hurt. We train for it, we harness for it, and we carry the insurance for it.
Roof and waterproofing work on an addition is not a weekend project. Getting the flashing details wrong means the next leak shows up somewhere worse and more expensive. Graham Stein has been doing this long enough to write out every cost before a single tool touches the floor, and the quote you get is the price you’ll pay. Call (831) 480-4497 when you’re ready to know what the repair or replacement will actually cost.
FAQs
A Tamko Heritage system installed correctly on a San Francisco addition should last 20 to 25 years, and Titan XT can push toward 30. The fog belt and salt air in outer Richmond and Sunset shorten that somewhat compared to interior neighborhoods. The biggest variable is the quality of the original installation – San Francisco additions built before 2008 often have underlayment and flashing issues that cut lifespan in half. Call (831) 480-4497 and we’ll look at the original build signs before recommending a repair versus a new system.
Yes, if the failure is isolated to one plane or one penetration, we can replace the damaged shingles, correct the flashing, and reseal the transition. The caveat is the Tamko adhesive formulation change: shingles from different years don’t always seal properly to each other. If the repair involves mixing old and new Tamko product, we’ll tell you honestly whether a patch will hold or whether you’re buying a temporary fix. Estimates are free.
Most addition and ADU roof replacements in San Francisco take three to six working days, depending on roof complexity, weather holds, and whether we find structural repair work underneath. We keep you posted on schedule daily and we set quiet hours so the work doesn’t chase your family out of the house. We’ll give you a written schedule before the job starts.
We keep standard Tamko underlayment, flashing, and sealants on the trucks, and common Heritage and Titan XT shingle bundles in our usual rotation. Custom colors or MetalWorks steel panels usually need a supplier order that takes three to five business days. When we order Tamko materials for your job, we order by the original bundle code where possible so the color match is as close as the product allows.
Written by Graham Stein, Owner, Elmstead Remodeling San Francisco at Elmstead Remodeling San Francisco, serving San Francisco and nearby areas.
