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IKO Home Additions & ADU: The Woodland Hills Owner’s Guide
Planning a home addition or ADU in Woodland Hills means choosing the right roofing and waterproofing system, and IKO is a common spec we work with across the area. A properly planned addition or ADU project here typically runs $45,000 to $130,000 for the addition itself, and $90,000 to $220,000 for a standalone ADU, including design, permits, foundation, framing, roofing, and finishes. Most owners come to us after realizing their existing roof line, drainage, or storage plans won’t survive another Woodland Hills summer without a serious conversation about how to build it right the first time.
We’re Mason Remodeling Co Woodland Hills, an independent contractor serving Woodland Hills and nearby areas. We’re not affiliated with IKO, but we’ve installed and repaired enough IKO-spec roofing and waterproofing on additions and ADUs to know exactly what works under Southern California sun, what fails early, and what the real installed cost looks like before you sign anything.
Which IKO Models This Applies To
IKO makes a broad range of asphalt shingles, underlayments, and waterproofing membranes, and the right choice depends on the slope, exposure, and fire zone of your Woodland Hills property. For most additions and ADUs we build here, owners are working with IKO architectural shingles like the Cambridge, Dynasty, or Nordic lines, or one of their cool-roof color profiles that meet California Title 24 energy requirements.
The compatibility question that trips up most homeowners is this: IKO shingles are rated for specific minimum slopes and specific underlayment pairings. A Cambridge shingle on a low-slope addition roof is not the same install as a Dynasty on a standard 6/12 pitch, and putting the wrong self-adhered underlayment under either one will void the IKO warranty and shorten the roof’s life in Woodland Hills heat. We verify the exact product code and install date printed on the original wrapper or delivery slip before we quote anything. OEM IKO materials are what we recommend for additions and ADUs that need to match an existing roofline, because color drift between OEM and aftermarket equivalents is real and gets more obvious every year in direct sun.
For waterproofing below grade and around foundations, where additions and ADUs often meet the existing slab, we commonly see IKO’s ArmourGard or similar peel-and-stick membranes. The gotcha there is surface prep: IKO self-adhered membranes need a clean, dry, primed substrate to bond. Skip that step in a rushed foundation pour and you’ll chase leaks around the transition for years.
Styles & brands we work with
Signs Your IKO Home Additions & ADU Is Failing
- Granule loss collecting in gutters. IKO architectural shingles shed granules as they age, especially on south-facing slopes in Woodland Hills. If you’re seeing a thick layer of granules in the gutter after every rain, the shingle’s UV protection is mostly gone and the mat underneath is starting to cook.
- Curling or lifting shingle edges near the ridge or hips. This is almost always an underlayment or ventilation problem, not a shingle defect. Attic heat builds up and cooks the shingles from below, and once the edges lift, wind gets under them and the damage accelerates fast.
- Water staining on the ceiling where the addition meets the original house. This is the classic addition failure point. The transition flashing between old roof and new roof is the most demanding detail on the whole job, and when it’s done wrong, the leak shows up inside first.
- Elevated attic temperature in the new space. If the addition or ADU feels hotter than the original house at the same thermostat setting, the roof ventilation probably wasn’t balanced for the new footprint. IKO shingles over a poorly ventilated deck won’t hit their rated lifespan.
- Cracked or brittle sealant at roof penetrations. Every vent pipe, skylight, and exhaust fan on an IKO roof is a potential entry point. Woodland Hills sees enough heat cycling each year that sealant dries out and separates faster than most owners expect, and a small crack becomes a ceiling stain within two or three winters.
See the difference
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AfterReplacement Cost & What’s Included
For the scope this page is about, full home addition and ADU construction in Woodland Hills runs $45,000 to $130,000. That’s for the addition including slab or raised foundation, framing, IKO-spec roof, stucco or siding, drywall, electrical, and basic finishes. A standalone ADU runs $90,000 to $220,000 depending on square footage, utility connections, and whether you’re doing a conversion or new construction.
Here’s what that includes when we price it:
- Written line-item price before any work starts. No verbal estimate that turns into a bigger number at the end.
- All permits pulled and inspections scheduled. The city and county both have a say in additions and ADUs in Woodland Hills, and we handle the paperwork.
- IKO roofing and waterproofing installed to manufacturer spec. That means the right underlayment, the right fasteners, the right flashing details, and the right ventilation balance.
- 365-Day Done Right Promise. If something isn’t right within a year of completion, we make it right at no cost to you.
What drives the range on the low end versus the high end: foundation conditions, utility tie-in distance, roof complexity (a simple gable costs less than a multi-plane roof with hips and valleys), and finish level. A second story addition almost always out-costs a single-story bump-out of the same square footage because of structural engineering and roof tie-in work.
DIY or Call Us?
There is a real safety line here, and we draw it plainly: anything involving roof structure, load-bearing walls, foundations, or electrical connections is professional work. Falling from a roof or having a wall shift during a botched header removal are not risks worth taking. The same goes for gas line work if your ADU includes a kitchen or laundry.
What you can safely do before calling us: gather your property’s original floor plan if you have it, check your lot’s setback and zoning notes from the city’s planning portal, and walk the existing roofline to look for the failure signs above. That homework helps us quote faster and more accurately. But the actual building, the roofing, the waterproofing, the permits, the inspections, that’s work you want a crew with verified identities, written pricing, and a warranty standing behind. Call (831) 290-6866 and tell us what you need done. We’ll tell you what it takes and what it costs. Then we get to work.
FAQs
An IKO architectural shingle roof properly installed over a well-ventilated deck in Woodland Hills typically lasts 18 to 25 years, with south-facing slopes on the shorter end of that range because of UV load. Call (831) 290-6866 and we’ll evaluate your specific roof.
Yes, if the damage is limited to a few shingles, flashing points, or sealant lines, targeted repair makes sense and runs $400 to $1,800 for most Woodland Hills roofs. If the shingles are curling across entire slopes or granules are covering the gutters, repair becomes patchwork, and replacement is the honest answer.
A single-story addition in Woodland Hills typically takes 4 to 7 months from permit submission to final inspection. A standalone ADU runs 6 to 10 months. Many things affect that timeline, including city plan check turnaround and utility connection scheduling, and we state the expected schedule in writing before we start.
We order IKO materials per project to match the exact product line and color already on your home, not what happens to be sitting in inventory. That prevents the mismatched-roof look that comes from close-enough shingle matching. Call (831) 290-6866 and we’ll spec the right IKO product for your job.
Have an IKO roof on an existing home and planning an addition or ADU in Woodland Hills? Call (831) 290-6866 to schedule your free estimate. We’ll send a written price before any work begins, and the crew that shows up will be the crew we told you was coming, by name and photo, before they reach your door.
Written by Isaac Pruett, Owner, Mason Remodeling Co – Woodland Hills, CA at Mason Remodeling Co Woodland Hills, serving Woodland Hills and nearby areas.
