Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
IKO Home Additions & ADU: The Los Angeles Owner’s Guide
We stock and install IKO-compatible materials for home additions and ADU construction across Los Angeles, and a full addition or ADU build typically runs $53,100 to $153,400 depending on square footage, site prep, and finish level. Most owners realize they need professional help when their existing IKO roofing, waterproofing, or structural sheathing starts failing around the addition’s roofline, causing leaks, sagging, or visible delamination at the seams. We’re an independent contractor, not affiliated with IKO, which means we match the right material to your existing build rather than pushing one brand line.
What you’re likely dealing with: water intrusion at the transition point where an old roofline meets a newer addition, failed flashing around dormers or bump-outs, or sheathing that has absorbed moisture and lost its structural rating. Isaac Pruett has seen all of it during nearly two decades of Los Angeles remodels, and the fix usually starts with understanding exactly which IKO product line was used and how it was installed.
Key Takeaways
- Installed cost for a home addition or ADU in Los Angeles: $53,100 – $153,400
- We match IKO materials to your existing roofline, flashing, and sheathing before work begins
- Written price delivered before any work starts, on every project
- Every completed job carries a written guarantee with clearly stated terms
- Call (803) 680-2547 for a free estimate on your IKO-related addition or ADU project
Which IKO Models This Applies To
IKO manufactures a range of asphalt shingles, underlayment, and waterproofing membranes commonly used on Los Angeles home additions and ADUs. The most common lines we encounter on addition work are the IKO Cambridge architectural shingle series and the IKO Dynasty line, along with IKO’s StormShield and AquaBarrier underlayments used at transition points. Compatibility gets tricky because IKO changed some shingle dimensions and sealant strip configurations between production years, so a Cambridge shingle from 2018 will not always lock correctly against a Cambridge batch from 2024.
We identify the exact material by pulling a shingle sample and checking the manufacturing code on the back of the sheet, then measuring the exposure and sealant strip width. For additions where the original roof is older, we often find the original IKO line has been discontinued or reformulated, which is where a quality aftermarket equivalent from GAF, CertainTeed, or Owens Corning sometimes makes more sense than forcing a mismatched IKO product. That decision is made on the roof, with a written recommendation, not in a showroom. We also stock and install complementary systems from KraftMaid for cabinetry and Cambria or Silestone for countertops on ADU interior finishes.
Styles & brands we work with
Signs Your IKO Home Additions & ADU Is Failing
- Ceiling staining at the addition’s roofline. The most common first sign. Water is getting past the flashing or underlayment where the new roof ties into the original structure, and it follows the truss line until it shows up inside.
- Granule loss in gutters or downspouts. IKO shingles shed granules as they age, and in Los Angeles heat cycles the asphalt layer breaks down faster than in cooler climates. If you see heavy granule buildup, the shingle has entered the back half of its life.
- Wavy or lifting shingles along the ridge or transition lines. This usually means the sealant strip has failed and wind is getting underneath. On Los Angeles hillside lots, the afternoon wind off the canyons accelerates this once it starts.
- Damp or soft sheathing in the attic near the new framing. By the time you can feel it, the IKO underlayment has been compromised for months. The sheathing likely needs replacement, not just the surface layer.
- Cracking or peeling at interior seams where the addition meets original walls. Movement between the old foundation and the new addition can telegraph through drywall and trim. It’s not always a roof issue, but it often shows up at the same time and needs to be addressed before new materials go on.
See the difference
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AfterReplacement Cost & What’s Included
A full home addition in Los Angeles currently runs $53,100 to $153,400, and an ADU construction project spans $106,200 to $259,600 depending on whether you’re building detached, attached, or converting a garage. Lower-end numbers cover straightforward builds with standard IKO shingles, basic finishes, and a simple foundation. Upper-end pricing reflects site grading challenges, hillside engineering, custom cabinetry, and higher-spec materials like Cambria or Silestone countertops.
Every quote includes all material, labor, fasteners, flashing, underlayment, sheathing replacement where needed, and any haul-off of the old material. You get a written price before any work starts, and that price does not move unless you change the scope. Every job carries a written guarantee stating exactly what is covered and for how long, starting from the completion date. If a repair or installation fails, we return free of charge. No dispute process, no conditions.
What Drives the Price Range
- Structural scope: A simple bump-out costs less than a full second-story addition that requires engineered beams and foundation work.
- Site access: Hillside lots, narrow streets, or limited staging areas in neighborhoods like Silver Lake, Echo Park, or Mount Washington add labor hours and equipment needs.
- Finish level: Builder-grade fixtures versus specification-grade products from Kohler, Moen, Toto, and Grohe. The gap is real and it shows up in the final number.
- Roof integration: Matching IKO materials to an existing roofline, or replacing the entire roof if the old material is too far gone, moves the price meaningfully.
- Permit and plan costs: Los Angeles requires plans, structural calculations, and inspections for additions and ADUs. We pull permits and manage the inspection process as part of the scope.
DIY or Call Us?
If you want to understand the scope, you can safely check a few things yourself: look at the shingle edges along the addition’s roofline for curling or lifting, check gutters for granule buildup, and look for staining in the attic near the transition point. That’s a useful starting point before you call. But the actual repair or rebuild is not a weekend project. Roof work at height, structural framing, foundation ties, and IKO material matching all carry real risk, and a wrong step on a steep Los Angeles hillside roof turns expensive into dangerous.
If you’re dealing with a failed roofline transition, cracked framing, or water intrusion inside the addition, call us at (803) 680-2547. We’ll put eyes on the actual condition, give you a written price, and if work isn’t needed, we’ll tell you that too. Know who’s coming, know what it costs, know it’s backed up. Everything else is just noise.
FAQs
IKO architectural shingles generally last 20 to 30 years in Los Angeles, but the underlayment and flashing at the addition’s transition points wear faster due to heat cycling and repeated expansion and contraction. Expect to inspect and often replace transition flashing every 10 to 15 years even if the shingles look fine. Call (803) 680-2547 and we’ll look at what’s actually happening up there before you spend anything.
Yes, if the shingle surface is intact and the issue is localized to flashing, sealant strips, or a specific section of sheathing, a targeted repair is often the right call. If the IKO product line has been discontinued or the granule loss is widespread, replacement makes more economic sense than chasing leaks. We give you the repair option and the replacement option in writing, with prices for both.
A straightforward addition typically takes 10 to 16 weeks from first day of work to final inspection, and an ADU runs 16 to 24 weeks depending on site conditions and the city’s plan review schedule in Los Angeles. Permitting time before construction starts varies, and we handle that process for you. You’ll get a realistic schedule in writing with your quote.
We maintain relationships with IKO distribution partners across Los Angeles and pull materials as needed for each job, matched to the existing roofline by sample and manufacturing code. You don’t have to order anything yourself, and you’ll see the exact product and price on the written quote before work begins. Call (803) 680-2547 for a free estimate.
Written by Isaac Pruett, Owner, Mason Remodeling at Mason Remodeling, serving Los Angeles and nearby areas.
