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
If you’re planning an addition or ADU build with IKO roofing and waterproofing products, you’re looking at a project that typically runs $53,100 – $153,400 in Los Angeles depending on square footage, foundation work, and finish level. We install and integrate IKO shingles, underlayment, and flashing systems on additions and ADUs across the LA Basin, and we can usually get your project scoped and priced within a week of the first walkthrough. The most common call we get starts with a homeowner who’s been told by a city inspector or a roofer that their planned addition needs IKO-compatible underlayment and flashing details before anyone will sign off on the permit.
Key Takeaways:
- Los Angeles additions and ADUs with IKO roofing systems run $53,100 – $153,400 depending on size and scope
- IKO compatibility matters most at the roof-to-wall transitions and the foundation line, where failed flashing causes the majority of repairs
- Permits in Los Angeles for ADUs and additions typically require approved underlayment and flashing materials, and IKO products meet those specs
- We’re an independent Los Angeles remodeling contractor, not affiliated with IKO, but we know their product line and install it correctly
Which IKO Products This Applies To
IKO makes a range of asphalt shingles, synthetic underlayments, ice and water shields, and flashing components. The most common product families we work with on Los Angeles additions and ADUs are the IKO Cambridge shingle line, the Dynasty line for higher wind ratings, and the RoofGard underlayment system. If you’re matching an existing roofline on your Los Angeles home, you’ll want to confirm the shingle profile and color code, which is printed on the wrapper of a leftover bundle or on the original invoice from your roofer.
Here’s the thing about IKO on additions specifically: the weak points are never the shingles themselves. They fail at the transitions. Where the new addition roof ties into the existing structure, where the ADU roofline meets the main house, where flashing runs along a stucco wall. IKO’s adhesive strips and granule blend hold up fine in Los Angeles sun and rain. It’s the installer’s flashing details that separate a roof that lasts 25 years from one that leaks in three. We spec IKO’s StormShield ice and water shield at every valley and wall transition on LA additions, because that’s where water actually gets in.
If you’re buying IKO materials directly, check the pallet labels for the plant code. IKO runs multiple manufacturing plants, and shingle granule blends vary slightly between them. Matching bundles from the same plant gives you a uniform roofline. We’ve pulled bundles off the same Home Depot shelf in Los Angeles that came from two different plants, and the color difference showed up on the roof. That’s the kind of gotcha you don’t want to learn about after the shingles are nailed down.
Styles & brands we work with
Signs Your IKO Home Additions & ADU Installation Is Failing
Most Los Angeles homeowners don’t notice a failing IKO installation until water shows up where it shouldn’t. Here’s what we typically find on the first inspection:
- Water staining at the ceiling-wall junction where the addition meets the original structure. This is almost always a flashing detail that wasn’t properly integrated with the existing roof. In Los Angeles, the first heavy rain of the season reveals these within minutes.
- Lifted or curling shingles on the south-facing slope. Los Angeles UV exposure is brutal on asphalt shingles, and IKO shingles that weren’t nailed to the correct placement spec will curl at the corners after a few summers. The nail line is printed on the shingle itself, and missing it by even half an inch causes premature failure.
- Granules collecting in the gutters after every rain. Some granule loss is normal in year one. A steady stream of grit after year three means the shingles are curing too fast, often because the underlayment wasn’t ventilated properly under an LA sun.
- Damp spots on the interior wall below a roof valley. Valley metal that’s too narrow, or IKO’s StormShield not extended far enough up the valley walls, lets water ride right under the shingles during a hard LA downpour.
- Mold smell in an ADU that’s less than two years old. This is usually a crawlspace ventilation issue combined with an underlayment that’s trapping moisture rather than shedding it. IKO’s synthetic underlayments breathe better than felt, but the venting still has to be right.
Replacement Cost & What’s Included
A full addition or ADU build in Los Angeles with IKO roofing integrated runs $53,100 – $153,400. That’s the all-in range for most of what we quote, and the spread comes down to three things: the size of the addition, the condition of the existing structure you’re tying into, and the finish level you choose inside. A 400-square-foot bedroom addition with a simple gable roof on a flat Lot in the San Fernando Valley sits at the lower end. A 1,200-square-foot ADU with a full kitchen, bathroom, and a tied-in roofline that requires re-roofing half the main house lands at the upper end.
Here’s what that price includes when we do it: a written line-item quote before any work starts, all permits pulled and inspections scheduled, IKO shingles and underlayment installed to manufacturer spec, all flashing and tie-in details done with IKO StormShield, and our 365-Day Done Right Promise in writing. If something fails inside that year, we come back and fix it at no charge. No service call, no re-inspection fee. The number you sign is the number you pay, and the quote itemizes the IKO materials separately so you can see exactly what the roofing portion costs.
For Los Angeles specifically, soft-story and hillside lots add foundation and engineering costs that flat-lot homes don’t carry. If your ADU sits on a slope, expect to be at the higher end of the range. If it’s a simple detached garage conversion with an existing slab, you’ll be lower.
See the difference
Before
After
Before
After
Before
AfterDIY or Call Us?
If you’re building an addition or ADU that requires IKO roofing installation, this is not a DIY project. We’ll say that plainly. The shingle installation itself isn’t the danger. The danger is working at height on a roof, and the bigger risk is a tied-in roofline that leaks because the flashing wasn’t lapped correctly. You can absolutely handle the planning work yourself: measure your lot, check your setback requirements with LA City Planning, and confirm your IKO shingle color and line before you talk to any contractor. That saves you time and gives you more control over the quote.
What you shouldn’t do is climb a ladder to inspect the existing flashing or try to pull up shingles to see what’s underneath. Roof work on a two-story Los Angeles home is dangerous, and a fall onto concrete or stucco isn’t worth the inspection fee you’d save. Call us at (213) 277-6578 and we’ll do a full evaluation on the ground and with a drone before we ever put a boot on your roof. Trevor Nash has spent two decades working residential jobs across the Basin, and his rule is the same now as it was on his first job: give you a number first, then pick up the tools.
Frequently Asked Questions
IKO’s Cambridge and Dynasty lines carry 25-30 year warranties, but in Los Angeles UV and heat exposure realistically puts useful life at 18-25 years depending on slope, ventilation, and whether the roof faces south. A well-ventilated north-facing roof in Sherman Oaks will outperform a poorly vented south-facing roof in Woodland Hills every time. We quote IKO Dynasty on most LA additions because the higher wind rating and thicker shingle simply hold up better through our hot summers and Santa Ana seasons. Call (213) 277-6578 to talk through which IKO line makes sense for your specific roofline.
Yes, if the failure is localized to flashing details or a few lifted shingles. If the underlayment is compromised or the shingles are curling across more than 30% of the roof, spot repairs just buy you a year or two before you’re back in the same situation. In Los Angeles we see a lot of additions where a previous contractor cut corners on the tie-in flashing, and those are usually repairable without a full re-roof. We’ll tell you straight which situation you’re in, and we’ll put the recommendation in writing either way. Estimates are free at (213) 277-6578.
Most of our Los Angeles additions and ADUs take 4-8 months from permit approval to final inspection, and roofing is usually a 3-5 day portion of that timeline. The variables are City of Los Angeles plan check times, which vary by district and workload, and whether your project triggers any hillside or historic overlay reviews. We handle the permits and inspections as part of the job, and we’ll give you a written timeline with your written quote. Call (213) 277-6578 and we’ll walk you through a realistic schedule for your zip code.
We source IKO materials directly from Los Angeles roofing supply yards the moment your permit clears, so you get fresh stock from a single plant run, not mixed pallets that have been sitting in a warehouse. We don’t stock IKO shingles on a shelf in advance, because shingles absorb moisture and heat in storage, and fresh bundles from a single production batch install and age more consistently. We also work with KraftMaid, Cambria, and Silestone for the interior portions of your addition or ADU, so the entire project ships through familiar supply lines. The IKO portion of your invoice itemizes every bundle and roll separately.
Call Penhallow Remodeling Los Angeles
If you’re planning an IKO-roofed addition or ADU in Los Angeles and want a real number before anyone swings a hammer, call (213) 277-6578 for a free estimate. We’ll come out, walk the site, and hand you a written line-item quote with the IKO materials broken out, the permit path explained, and our 365-Day Done Right Promise in writing. A live person answers the phone 24/7, no voicemail maze. Trevor Nash and the Penhallow team have been building and remodeling across Los Angeles long enough to know that the only thing better than a roof that doesn’t leak is knowing the price before the first nail goes in.
Written by Trevor Nash, Owner, Penhallow Remodeling Los Angeles at Penhallow Remodeling Los Angeles, serving Los Angeles and nearby areas.
