Tamko Home Additions & ADU Nationwide

Tamko Home Additions & ADU: The Cupertino Owner’s Guide

We stock and install Tamko-compatible components for home additions and ADU projects throughout Cupertino, with typical installed pricing from $45,000 to $130,000 for additions and $90,000 to $220,000 for standalone ADUs. Most homeowners first discover an issue when a permit inspection flags a roofing or flashing detail that doesn’t match the approved Tamko spec, or when water intrusion appears at the addition-to-existing wall junction after the first winter rains in the Santa Clara Valley. We carry the full Tamko Heritage series, Titan XT, and StormFighter IR lines, and we can match sheathing, underlayment, and ventilation components to your original build documents.

Call (669) 202-9618

Which Tamko Models This Applies To

Tamko’s residential roofing and waterproofing systems appear in Cupertino additions and ADUs across three main product families. The Heritage series, including Heritage Vintage and Heritage Woodgate, is the most common on additions built between 2010 and 2020. Titan XT, with its reinforced nailing zone, shows up frequently on ADUs completed after 2018 when Santa Clara County adopted stricter wind-uplift requirements. StormFighter IR is specified less often but required in certain Monta Vista and Rancho Rinconada neighborhoods with elevated fire-risk designations.

To identify your system, check the edge of any loose shingle for the Tamko stamp, or look for the original permit packet - Cupertino Building Division requires roofing manufacturer documentation on file for all additions and ADUs permitted after 2015. The model number matters because Heritage and Titan XT use different underlayment weights: Heritage calls for a standard synthetic underlayment, while Titan XT pairs with a heavier 30-pound felt or synthetic equivalent to maintain the enhanced warranty. We source OEM Tamko components and have verified equivalents from GAF and Owens Corning when the original spec is discontinued, which happened with the Heritage 30-year laminate in 2019. Using a non-matching underlayment with a Titan XT shingle voids the wind warranty - that’s the compatibility gotcha we catch in pre-construction review.

Signs Your Tamko Home Additions & ADU Is Failing

• Granule loss visible in gutters or at downspout exits. Tamko shingles shed granules normally for the first two years, but accelerated loss after year five usually indicates the thermal cycling common in Cupertino’s south-facing exposures has degraded the asphalt binder. We check granule depth with a simple gauge; below 2mm, the shingle’s UV protection is compromised.
• Lifted or cupped shingle edges along the addition’s rake or eave. This points to inadequate attic ventilation, a frequent issue in ADUs with converted garage footprints where the original venting was never recalculated. Tamko’s warranty requires 1 square foot of net free vent area per 150 square feet of attic floor; many Cupertino ADUs fall short.
• Water staining on interior drywall at the marriage wall - the junction between existing structure and new addition. The step flashing detail here is where Tamko’s rolled waterproofing membrane should integrate with the existing wall’s weather barrier. Separation at this joint is the most common leak source we find in Cupertino inspections, often because the membrane was cut too short during original construction.
• Brittle shingles that crack when walked for satellite dish or solar panel maintenance. After eight to ten years in Santa Clara Valley sun, Tamko’s organic mat shingles lose flexibility faster than fiberglass-core alternatives. We see this most on west-facing ADU roofs in the Monta Vista area where afternoon exposure peaks above 180 degrees surface temperature.
• Moss or algae streaking concentrated on the north slope. Cupertino’s marine-influenced microclimate keeps north-facing surfaces damp for months. Tamko’s algae-resistant granules wear off predictably; the staining is cosmetic but signals that the protective layer is thinning and the substrate is holding moisture longer than designed.

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Replacement Cost & What’s Included

What drives the range: roof pitch (steeper means more labor per square), access for tear-off equipment, whether the original deck needs replacement, and whether we’re matching a discontinued Tamko color to the existing home. Under Clause 1 of The Haven Standard, your written quote itemizes each of these - no aggregate lump sum. The price you sign is the price you pay; no change order moves forward without your signature, which is the discipline that has kept our projects within a few percent of estimate across 4,000-plus jobs. Our 365-Day Done Right Promise covers the workmanship; Tamko’s material warranty runs 30 to 50 years depending on series, and we register it in your name at completion.

DIY or Call Us?

There’s a safe middle ground for homeowners. You can walk the roof with binoculars from a ladder to spot obvious damage, check the attic for daylight through the deck, and verify your venting math with a tape measure. What you should not do: remove shingles to inspect the underlayment, attempt to reseal the marriage wall membrane, or replace step flashing - these require proper ladder tie-off, knowledge of where the existing electrical and plumbing penetrates the wall, and the ability to integrate new waterproofing with old without creating a dam. Falls from single-story ADU roofs account for a significant share of residential construction injuries in Santa Clara County. We carry Tamko-compatible membrane, flashing, and ventilation components on our trucks, and we document every repair with a photo record you receive before we leave. Call (669) 202-9618 to schedule your free estimate - we’ll inspect, itemize, and quote in writing.

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