Tamko Home Additions & ADU Nationwide

Tamko Home Additions & ADU: The Redwood City Owner’s Guide

Tamko-compatible roofing and exterior components for home additions and ADUs in Redwood City typically run $45,000-$130,000 for full addition builds and $90,000-$220,000 for detached ADU construction, with Tamko Heritage and Titan XT shingles being the most commonly specified lines we see on Peninsula permits. We stock Tamko shingles and matching ridge caps on our Redwood City trucks, and most homeowners who call us have already noticed the problem: a new addition or ADU roof that doesn’t match the main house, or a Tamko roof on an older structure that’s failing before the addition’s framing is even complete. In Redwood City’s climate, with marine layer moisture rolling off the bay and baking afternoon sun in neighborhoods like Stambaugh-Heller, mismatched or incorrectly specified Tamko products show stress faster than almost any other call we get.

Call (650) 560-7228

Which Tamko Models This Applies To

The Tamko lines we specify and replace most often on Redwood City additions and ADUs are the Heritage series (Heritage, Heritage Premium, Heritage Woodgate), the Titan XT impact-rated line, and the discontinued Lamarite slate composite, which we still encounter on 2010-2018 builds in the Emerald Hills area. The Heritage series uses a 130-mph wind rating and a 30-year limited warranty for standard Heritage, 50-year for Premium; Titan XT bumps that to 160 mph with a Class 4 impact rating, which matters because Redwood City’s 2023 building code update requires impact-resistant roofing on all new detached ADUs over 400 square feet.

To identify your Tamko product, check the shingle back for the printed date code and series name, or look for the Tamko-specified ridge vent if the shingles themselves aren’t accessible. The OEM part question for Tamko is straightforward: we source factory-direct Heritage and Titan XT shingles through Tamko’s West Coast distribution in Stockton, but for ridge caps, starter strips, and underlayment, we often specify Atlas or Owens Corning equivalents that meet the same ASTM D3462 standard at lower per-square cost. The compatibility gotcha in Redwood City is the color match: Tamko’s “Weathered Wood” from 2019 production runs noticeably cooler in tone than 2024 stock due to a granule supplier change, and we’ve learned to pull a physical sample before ordering for any addition tie-in.

Signs Your Tamko Home Additions & ADU Is Failing

• Granule loss exposing black asphalt substrate. Redwood City’s combination of fog-laden mornings and 90-degree summer afternoons accelerates thermal cycling, and we’ve found Heritage shingles on south-facing ADU roofs in Farm Hills losing granules at year 12 instead of the expected 18-22. The underlying cause is UV degradation of the asphalt mat once the ceramic granule shield thins.
• Curling or clawing at shingle edges. This happens when the addition’s roof ventilation was spec’d for the main house volume but not the smaller ADU cavity, trapping moisture and heat. We see this most on garage conversions in Mount Carmel where the original Tamko roof was retained and the space was enclosed without adding soffit vents.
• Water staining on new interior drywall below the addition roofline. The leak point is rarely the field shingles; it’s the step flashing where the addition meets the existing structure, or the Tamko ridge cap that was hand-cut instead of using the factory-matched preformed unit. Redwood City’s driving winter rains find these gaps in November through February.
• Shingle tabs cracking in a diagonal pattern. This is thermal shock from inadequate attic insulation above the ADU, a common issue in Redwood City’s 1950s ranch additions where the original R-19 batts were never upgraded. The Tamko shingle flexes daily; without temperature moderation, it fatigues at the fastening point.
• Moss or algae streaking concentrated on the north slope. Redwood City’s marine layer provides ideal growing conditions. Tamko’s algae-resistant granules (the AR suffix on Heritage AR) have a 10-year effectiveness window; after that, the organic growth retains moisture against the shingle and accelerates decomposition of the asphalt binder.

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Replacement Cost & What’s Included

The range driver is always what’s underneath. We don’t know if your addition’s sheathing is 1x skip sheathing from a 1960s build or modern OSB until we open it, and we won’t guess in the quote. Under Clause 1 of the Haven Standard, the written price you receive before work starts includes a line item for sheathing replacement at $3.50-$5.00 per square foot if needed, with a photo of the actual condition attached to your estimate. No change proceeds without a signed change order, which is the discipline that has kept our projects within a few percent of the agreed number across 4,000-plus jobs.

Our 365-Day Done Right Promise covers the Tamko installation specifically: if a nail pops, a shingle lifts, or a valley leaks in that first year, we repair it at no charge and document the fix with the same photo record you received on day one.

DIY or Call Us?

There’s a safe middle ground for homeowners who want to understand the problem before calling. You can check your Tamko shingles for the date code and series name from a ladder at the eave, verify whether your addition has soffit and ridge vents by visual inspection, and photograph any interior staining for reference. What you should not do is walk a Tamko roof that’s steeper than 4:12 pitch, attempt to lift shingles to check fasteners, or replace ridge caps yourself. The fasteners on a Tamko Heritage shingle are hidden by the overlapping tab above; disturbing that seal breaks the self-adhesive strip and voids the wind warranty.

For ADU and addition work specifically, Redwood City requires a building permit for any roof replacement over 100 square feet, and the inspector will want to see the Tamko specification sheet on site. We’ve had homeowners call us after a DIY re-roof failed inspection because the starter strip was omitted or the valley was woven instead of cut, both of which are code violations under the 2022 California Residential Code adopted here. Call (650) 560-7228 and we’ll schedule a free estimate with a written price before any work starts. Measure twice, document once, build it so it doesn’t come back.

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