Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Tamko Home Additions & ADU: The Los Angeles Owner’s Guide
A Tamko home addition or ADU project in Los Angeles typically runs $53,100 – $153,400 installed, and the parts that fail first are rarely the roofing or siding materials themselves. More often, it’s the connection points: flashing, transition strips, underlayment seams, and the places where a Tamko surface meets a wall, window, or door. Homeowners usually discover the problem after a heavy rain season, when a stain creeps across the ceiling or a musty smell settles into a converted garage.
If you’re standing in a room that was added or converted and something isn’t right, the part that failed usually has a Tamko-specific profile or installation requirement. We keep compatibility parts on hand for the Tamko systems commonly installed across Los Angeles, and we write the price down before any work starts. Call (213) 277-6578 and you’ll get a real person, not a voicemail tree.
Which Tamko Models This Applies To
Tamko makes a broad line of building products, but for home additions and ADUs in Los Angeles, the relevant systems are their roofing shingles, waterproofing membranes, and deck/underlayment products. The most common compatibility issue we see is between Tamko’s self-adhered underlayments and non-Tamko flashing. Tamko’s membrane products are engineered to bond with their own flashing accessories, and when a previous contractor cut corners with generic off-the-shelf flashing, the seam fails at the transition. That’s the part we end up replacing most often.
To identify what you need, look for the Tamko product label on any leftover material or the original permit paperwork from your addition. The label will show a product name and lot number. If the label is gone, the profile and texture of the shingle or membrane will tell us what we’re working with. We install Tamko-compatible parts and materials, and we’ll tell you plainly when an aftermarket equivalent will hold up just as well and when it won’t. Penhallow Remodeling Los Angeles is an independent contractor, not affiliated with Tamko, so our recommendation is based on what performs in this climate, not what a brand catalog pushes.
Styles & brands we work with
Signs Your Tamko Home Addition or ADU Is Failing
- Water staining at ceiling corners or around windows. This usually means flashing at the transition point has separated or was never installed correctly against the Tamko membrane. The stain is where water has already traveled; the actual failure point is usually a few feet away.
- Bubbling or peeling paint on interior walls of the addition. Moisture is trapped behind the surface, which often traces back to a failed underlayment seam or an unsealed penetration where the Tamko material meets a pipe vent or exhaust flue.
- Shingle granules collecting in gutters or at the base of downspouts. Los Angeles sun degrades asphalt shingle surfaces differently than wetter climates. Granule loss means the protective layer is thinning, and the exposed asphalt will start cracking within a season or two.
- A recurring musty smell in the ADU after rain. That odor is mold activity, and it needs a failed water barrier to sustain it. The source is almost always a transition point rather than the center of a roof or wall field.
- Visible waviness or sagging at the roofline where the addition meets the original structure. This is a structural connection issue, not just a surface problem, and it means the framing, flashing, and underlayment are all likely involved. Don’t wait on this one.
Replacement Cost & What’s Included
For Tamko-related repair and replacement work on home additions and ADUs in Los Angeles, the job usually falls between $470 and $2,125 when it’s a repair, and $53,100 to $153,400 when the addition itself needs replacement or rebuilding. Repair work covers flashing replacement, membrane patching, seam resealing, and localized shingle replacement. Full additions or ADU rebuilds include framing, roofing, waterproofing, interior finishes, and all required permits and inspections.
What drives the price up or down depends on access (is the failure point reachable from a ladder or do we need scaffolding?), the extent of water damage hidden behind the surface, and whether your addition requires matching Tamko materials that cost more than generic equivalents. Every quote is written, itemized, and fixed before work starts. The number we hand you on day one is the number on the invoice, covered by our 365-Day Done Right Promise, which means if it fails inside the guarantee period, we come back and fix it at no charge.
See the difference
Before
After
Before
After
Before
AfterDIY or Call Us?
There are a couple of things you can safely check: look for missing shingles from the ground with a pair of binoculars, check that downspouts are clear and directing water away from the addition, and look for daylight coming through any roof penetrations from inside the attic space. Those observations help us diagnose faster.
What you shouldn’t do is climb onto a roof with a tube of sealant and start patching. Roof work on any structure is dangerous, and a failed patch on a Tamko system can create a bigger water problem than the original leak. The membrane may have a small visible breach but a much larger adhesion failure you can’t see. If you’re not sure what you’re looking at, call (213) 277-6578 and describe what you see. We’ll tell you over the phone whether it needs a visit, and the estimate is free.
Key Takeaways
- A Tamko home addition or ADU repair in Los Angeles typically runs $470 – $2,125; full additions run $53,100 – $153,400.
- Most failures happen at transition points, not in the middle of a field.
- We write the price first, and the 365-Day Done Right Promise is in writing on every job.
- A live person answers at (213) 277-6578 around the clock.
FAQs
In Los Angeles’s UV-heavy, low-rain climate, a well-installed Tamko shingle roof typically lasts 15 to 25 years, while membranes and underlayments perform for 10 to 20 years depending on sun exposure and how well the transitions were flashed. Sun damage, not rain, is the bigger aging factor here. Call (213) 277-6578 and we’ll give you an assessment based on what’s actually on your addition.
Yes, if the failure is localized, which covers most flashing, seam, and small-area membrane breaches. Full replacement is only called for when water has compromised the underlying structure or the material has aged past its useful life. We’ll show you the difference and give you a written price either way before any tools come out.
Most transition-point repairs and flashing replacements take a single day. Larger membrane or roofing repairs can run two to three days. We’ll give you a defined arrival window and a written schedule before we start, not after.
Our technicians carry common flashing profiles, sealants, compatible underlayment materials, and fasteners on every truck. For specialized Tamko products with specific lot-matching requirements, we source them direct from a Los Angeles distributor, usually within one to two business days.
If your Tamko home addition or ADU is showing a leak, granule loss, or a transition failure, call (213) 277-6578 today. Trevor and the team at Penhallow Remodeling Los Angeles will give you a number first, then pick up the tools.
Written by Trevor Nash, Owner, Penhallow Remodeling Los Angeles at Penhallow Remodeling Los Angeles, serving Los Angeles and nearby areas.
