Tamko Home Additions & ADU Nationwide | Barrett & Sons Construction

Tamko Home Additions & ADU: The Los Angeles Owner’s Guide

We install and build Tamko-compatible home additions and ADU structures across Los Angeles, with full permitted builds typically running $53,100 to $153,400 depending on size, foundation work, and finish level. If your Tamko branded roof system, underlayment, or flashing is failing on an existing addition, we can usually get a crew out within a few days to assess it. Most Los Angeles homeowners discover the problem the way you probably did: a water stain on the ceiling after a heavy rain, a shingle in the yard after a Santa Ana wind event, or visible sagging where the addition ties into the main house.

Call (877) 610-1318

Tamko makes roofing and waterproofing products, not the actual framing or drywall. But when you’re adding square footage or building an ADU in Los Angeles, the Tamko materials you spec at the roof and underlayment stage matter more than most people realize. The wrong underlayment or a sloppy tie-in at the existing roofline fails inside of two seasons here. We’ve torn open enough old additions in Van Nuys and Reseda to know exactly where those failures start.

Which Tamko Models This Applies To

Tamko’s product line splits into a few families that show up on Los Angeles home additions and ADUs. The Heritage series is the most common we see on pitched addition roofs. The Titan XT and StormShield lines show up where owners wanted impact-rated material, which matters if you’re in a Santa Ana corridor. For low-slope sections on ADUs, Tamko’s APP and SBS modified bitumen rolls are the usual call, and the compatibility gotcha there is torch-down versus peel-and-stick: they don’t mix on the same roof plane without a proper transition detail.

Here’s what you need to match the part correctly. Walk the addition and look at a shingle edge. Tamko stamps the back of most architectural shingles with a production code that includes a plant identifier and date. If the roof is under ten years old, the original packaging or the permit file for the addition will list the shingle model and color. For underlayment, peel back a small section at an eave or check the roof deck from inside the attic if it’s visible. If you’re not sure, one of our crew leads can identify the material in about ten minutes. We stock Tamko Heritage in several Los Angeles-common colorways on our trucks, and we can order the less common shades and the full Titan XT line for next-day delivery in most of the county.

On the OEM versus aftermarket question: for roofing and waterproofing, we recommend staying with Tamko material if the surrounding roof is Tamko. Mixing manufacturers on one roof plane voids most material warranties and creates visible color and granule mismatch. That’s not us being picky. It’s what the manufacturer requires, and we put it in writing so there’s no surprise later.

Signs Your Tamko Home Additions & ADU Is Failing

• Water stains on the addition ceiling, especially within 18 inches of where the addition meets the main house. This is the most common failure point on Los Angeles additions. The original builder often under-flashed that tie-in, and the Tamko underlayment and step flashing never got the chance to do their job. We open these up and replace the flashing detail before we touch the shingles.
• Granules washing into your gutters or collecting at the downspout. Tamko architectural shingles shed a little granule in the first year, but consistent granule loss after five or more years in Los Angeles sun means the asphalt is oxidizing. UV here is relentless, and a south-facing addition roof ages faster than the north side of the same house.
• Curling or lifting shingle edges on the sun-exposed slope. On a Tamko roof, curling typically starts at the eaves or on slopes that take direct afternoon sun. Once the mat saturates and dries repeatedly, the shingle loses its ability to lay flat. At that point the roof still keeps water out for a while, but the clock is running.
• Peeling or bubbling underlayment visible in the attic or at eaves. Tamko’s synthetic underlayments perform well, but a bad install leaves wrinkles that trap heat and eventually crack. If you can see wrinkled or split underlayment from the attic side, water is working its way in through the shingle layer during heavy rain.
• Sagging or soft decking when you walk the addition roofline. This is the serious one. Soft decking means water has been getting past the Tamko material for some time and the plywood or OSB under it is compromised. We don’t patch soft decking on a Los Angeles addition. We cut it out and replace the section, then layer the new Tamko material over solid substrate.

Replacement Cost & What’s Included

For a Tamko roof system on a Los Angeles home addition, a full tear-off and reroof on a 400 to 800 square foot addition runs roughly $9,440 to $23,600, which lines up with our roof replacement range. If you’re building new square footage or an ADU from the ground up, the full project range of $53,100 to $153,400 for a home addition and $106,200 to $259,600 for an ADU includes the Tamko roof system, underlayment, flashing, and the structural work under it.

What moves the price most on the roofing side is access. A second-story addition in a Los Angeles hillside neighborhood with poor ladder placement costs more than a single-story addition on a flat lot with a driveway right alongside. Decking replacement adds to the tab when we find soft spots, and we price that per sheet in writing before we order material. What’s always included: tear-off and disposal, new Tamko underlayment, ice and water shield at the tie-in and eaves, new flashing at every penetration, the Tamko shingles or membrane, and a written workmanship warranty. We pull permits on every eligible reroof, and the inspector signs off before we call it done.

DIY or Call Us?

If you’re comfortable on a ladder, you can check a few things safely. Look at the tie-in where the addition meets the main house from the ground with binoculars. Check your gutters after a rain for granules. Walk the attic and look for daylight through the decking. Those are all safe checks, and they’ll tell you whether you need to call us at (877) 610-1318.

The actual replacement work is where DIY goes wrong. Walking a steep Los Angeles addition roof without fall protection is how people end up in the ER, and that’s the honest truth. Peel-and-stick underlayment installed wrong creates a water trap instead of a water barrier. Torch-down Tamko material carries an open flame over your roofline, and we’ve seen DIYers catch fascia and eaves on fire. You don’t save money by doing this yourself. You trade contractor cost for hospital cost, and the roof still leaks. Call us for a free estimate instead.

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