Tamko Home Additions & ADU Nationwide

Tamko Home Additions & ADU: The Palo Alto Owner’s Guide

We stock and install Tamko-compatible components for home additions and ADU projects across Palo Alto, with typical installed pricing running $45,000-$130,000 for additions and $90,000-$220,000 for standalone ADU construction. Most Palo Alto homeowners discover a Tamko product issue during the permitting phase or mid-project, when a roofing membrane, underlayment, or flashing detail specified in the original plans turns out to be discontinued, back-ordered, or mismatched to the coastal climate. We carry current-series Tamko replacements and cross-compatible alternatives on our active jobs, and we can usually source same-day from our Peninsula supplier network.

Call (650) 446-9092

Which Tamko Models This Applies To

Tamko’s residential construction line breaks into three categories relevant to Palo Alto additions and ADUs: the Heritage series shingles (Heritage, Heritage Vintage, Heritage IR), the Titan XT impact-rated line, and the MetalWorks steel shingles. For waterproofing layers common to addition roof tie-ins, we see Tamko’s TW Metal Underlayment and the TAMKO Aromatic Polymer (TAP) self-adhered membranes specified on older plans.

Here’s how to identify what you’ve got. Check the shingle bundle wrap for a 10-digit code starting with “TAM” - the third letter tells you the series (H for Heritage, X for Titan). Membranes are trickier: TAP products have a black-and-gold roll label with a lot number; TW underlayment is gray with a white stripe every 36 inches. If you’re matching an existing roof on a Barron Park or Old Palo Alto addition, the color granule blend matters - Tamko’s “Weathered Wood” from 2018-2021 runs slightly redder than current stock, and we’ve learned to flag this before the delivery truck arrives.

OEM Tamko vs. quality aftermarket: for shingles, we specify Tamko direct to keep the warranty chain intact - a 30-year Heritage shingle warranty requires certified installation with Tamko-branded accessories. For underlayment and ice-and-water shield, we often substitute Grace Ice & Water Shield or Polyguard when the TAP line is back-ordered, with full documentation so your permit inspector sees an equal-or-better spec. Measure twice, write it down, then we talk.

Signs Your Tamko Home Additions & ADU Is Failing

• Granule loss exposing black asphalt. On Tamko Heritage shingles, this means the UV protective layer has worn through - common on south-facing addition roofs in Palo Alto where the marine layer burns off by noon and sun exposure runs 6-8 hours daily. The shingle is no longer protecting the waterproofing layer beneath.
• Curling or clawing at shingle edges. This happens when the fiberglass mat separates from the asphalt core, usually from thermal cycling - Palo Alto’s 40-degree winter lows to 85-degree summer peaks stress the lamination. On Titan XT shingles, this voids the impact-resistance rating.
• Water staining at addition-to-existing wall junctions. The step flashing or counter-flashing detail has failed, often because the Tamko membrane beneath was installed without proper overlap at the tie-in point. We see this most on 1980s-2000s additions where the original contractor used felt instead of self-adhered membrane.
• Soft spots in the roof deck when walked. Moisture has penetrated past the shingle and underlayment layers, compromising the OSB or plywood sheathing. On ADU roofs with low slope (below 4:12), this frequently traces to using standard Heritage shingles where a low-slope membrane system was required.
• Interior humidity spikes or mold odor in new space. The Tamko underlayment or vapor barrier detail is breached, allowing conditioned air to meet unconditioned cavity space. In Palo Alto’s crawl-space additions, this often means the TAP membrane was punctured during HVAC rough-in and never sealed.

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Replacement Cost & What’s Included

The spread reflects three variables: square footage, structural complexity (foundation work vs. above-grade build), and finishes. A 400-square-foot Palo Alto ADU with a simple gable roof, IKEA-grade kitchen, and vinyl windows lands near the bottom. A 1,200-square-foot two-story addition with custom board-and-batten siding, engineered hardwood, and a full kitchen with KraftMaid cabinets pushes the top.

Every Rowan quote is a flat written price with line-item breakdown - materials named by brand and spec, labor separated, permits and inspections listed separately. Under Clause 1 of the Haven Standard, that price is locked before any work starts; no change proceeds without a signed change order. Our 365-Day Done Right Promise covers the installation, and manufacturer warranties run direct to you. We also stock parts for KraftMaid, Cambria, and Silestone when your addition or ADU interior package needs matching.

DIY or Call Us?

There’s a clear line between what a Palo Alto homeowner can safely assess and where professional work becomes non-negotiable.

You can check: shingle granule loss from the ground with binoculars; attic moisture stains during daylight; and permit records at Palo Alto City Hall to confirm what underlayment was originally specified. These cost nothing and tell you whether you’re looking at cosmetic wear or systemic failure.

Don’t attempt: walking a pitched addition roof (steep grades above 6:12 are common in College Terrace and Professorville); removing shingles to inspect membrane; or disturbing flashing at a wall junction. The fall risk is obvious, but the less obvious danger is creating a leak path that wasn’t there - lifting a shingle tab breaks the sealant strip, and without proper replacement technique, you’ve introduced a failure point that won’t show until the next hard rain.

Structural work on additions and ADUs requires permits in Palo Alto regardless of who does it, and the city inspects for code compliance on shear walls, egress windows, and utility tie-ins. We pull permits as standard, not as an upsell. Call (650) 446-9092 to schedule your free estimate - we’ll inspect, document with photos, and deliver a written price before any work starts.

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