Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterIKO Home Additions & ADU: The Los Angeles Owner’s Guide
IKO home additions and ADU construction in Los Angeles typically runs $53,100 to $153,400 for a full build, and that price includes framing, roofing, windows, electrical, plumbing, and finished interiors. We stock the IKO-compatible structural and roofing materials needed to tie a new addition into your existing roofline, and most material packages for these projects arrive at our Los Angeles yard in three to five business days.
How most people find us: They’ve got an IKO roof on the house and a contractor who either won’t pull permits, won’t put the scope in writing, or disappeared halfway through the job. The roof is fine. The problem is nobody wants to tie new framing into an IKO system without knowing how the flashing, underlayment, and shingle courses actually mate up. That’s where we come in.
Which IKO Models This Applies To
The home addition and ADU work we do applies to almost every IKO asphalt shingle line sold in California, including Cambridge, Dynasty, Nordic, and Royal Estate. For Los Angeles specifically, the Cambridge Cool Colors series and Dynasty performance lines are the two we see most often on houses getting additions. The key difference that matters: IKO’s nailing strip and sealant placement varies slightly between the Cambridge and Dynasty lines, so the new shingles on an addition need to match the existing roof by line, not just by color. If you’ve got Cambridge on the main house and the contractor slaps Dynasty on the new gable, the color will look right from the street but the seal line won’t sit the same, and in five years the wind will tell you exactly where the cheap match was.
If you don’t know which IKO line is on your roof, check the permit packet from the last reroof, look at the underside of a torn-off shingle for a lot code, or call us and we’ll identify it on-site. We match OEM IKO spec for any addition, but we also carry aftermarket equivalents from GAF and CertainTeed when an IKO line has been discontinued. Our rule: never put a discontinued shingle on a new addition just because the old roof has it. Better to match the profile and document the difference than to build a brand-new leak.
Signs Your IKO Home Addition or ADU Is Failing
- Water staining at the seam where the addition roof meets the original house. This is the number one failure we fix in Los Angeles. The valley flashing wasn’t tied into the IKO underlayment correctly, and every rain since has been working its way under the shingles.
- Gaps opening between the addition framing and the existing wall. Los Angeles soil expands and contracts with the seasons, and a poorly tied addition will pull away from the house over two or three wet winters. If you can slip a paint scraper into the gap, the connection wasn’t bolted or strapped to code.
- ADU door that jams or binds in summer. That’s usually a foundation or framing problem, not a door problem. The addition is moving. On IKO-roofed additions in Los Angeles, the heat cycles on the new roof deck can also be a factor when the ridge vent wasn’t cut in right.
- Shingle granules collecting at the bottom of a downspout on the new section. A new IKO roof should not shed granules within the first two years. If it is, the shingles were likely damaged during install or the roof deck isn’t ventilating and the shingles are cooking from underneath.
- Popping or creaking from the addition roof line on hot Los Angeles afternoons. That’s the roof deck expanding against fasteners or trusses that were installed too tight. It’s a small sound that usually means a bigger framing correction is coming.
Replacement Cost & What’s Included
Full IKO home addition construction in Los Angeles runs $53,100 to $153,400 depending on square footage, foundation type, finish level, and whether you’re adding a bedroom, a full ADU, or a garage conversion. For IKO roof work on an addition only, budget $9,440 to $23,600 for a reroof of that new section, and $470 to $2,125 for a targeted leak repair at the tie-in point. Every quote we write includes the materials, labor, fasteners, flashing, underlayment, permit fees, and the final inspection sign-off. Nothing gets left out, and nothing gets added later without a written change order in front of you first.
Our workmanship on any IKO roof or addition carries a 90-Day Done Right Promise, written on the contract. If it’s not right, one call brings Tom Barrett back to make it right.
DIY or Call Us?
You can safely check the seam where the addition roof meets the house for missing or lifted shingles, check the downspouts for granule buildup, and look at the interior drywall around the new roofline for water marks. Those cost you nothing and they tell you what’s wrong.
What you should not do is climb onto a Los Angeles roof in July and start pulling up IKO shingles to find a leak. Roof work on a two-story addition means ladders, steep pitch, and an afternoon sun that turns shingles into a hot griddle. Falls from roofs and ladders put more homeowners in the hospital every year than any other home repair. If you’ve got water coming in, call us at (877) 610-1318 and we’ll put eyes on it. The estimate is free.
FAQs
An IKO architectural shingle roof on a new addition in Los Angeles should last 20 to 30 years, but a bad tie-in at the original roofline can fail in under five. The shingles don’t fail. The flashing work around the valley, the step flashing at the wall, and the underlayment seams are what go first. Call (877) 610-1318 for an inspection if the addition is older than ten years and you’ve never had the tie-in checked.
Yes, if the failure is isolated to flashing or underlayment at the seam, a repair usually runs $470 to $2,125 in Los Angeles. But if the shingles on the addition are cracked, curling, or shedding granules, patching won’t hold and you’re better off replacing the section now. Call (877) 610-1318 and Tom will give you an honest read on which one you need.
Most home additions and ADUs in Los Angeles take four to eight months from permit filing to final inspection. The bulk of that is city processing and inspections, not labor. We pull the permits on every eligible job and the permit inspector works for you, not for us, so we like having him on the job.
We keep flashing, underlayment, fasteners, and the most common IKO Cambridge and Dynasty shingle colors in our Los Angeles yard. Special-order colors or discontinued lines usually arrive in three to five business days. The fastest way to know is to call (877) 610-1318 with your IKO line and color, and we’ll check the yard while you’re on the phone.
We’ve been building home additions and ADUs across Los Angeles since 1998, and we carry the same premium brands in every trade: KraftMaid and Cambria in kitchens, Silestone in bathrooms, GAF and CertainTeed on roofs. Tom Barrett’s name, address, and license number are published and verifiable, so look us up before you sign anything. We’ll do it right the first time, or we’ll come back and make it right.
Call us at (877) 610-1318 to schedule a free estimate on your IKO home addition or ADU project. A live person answers the phone, and the quote will be in writing.
Written by Tom Barrett, Owner, Barrett & Sons Construction at Barrett & Sons Construction, serving Los Angeles and nearby areas.