IKO Home Additions & ADU Nationwide

IKO Home Additions & ADU: The Pomona Owner’s Guide

IKO-compatible roofing and waterproofing components for home additions and ADU projects in Pomona typically run $45,000-$130,000 installed, depending on whether you’re tying into an existing IKO Cambridge or Dynasty roof system or building a standalone ADU from the slab up. We stock IKO StormShield ice-and-water barrier, ArmourGard synthetic underlayment, and matching Cambridge architectural shingles for same-day pickup or next-morning delivery to most Pomona job sites. Most Pomona homeowners discover their IKO addition needs attention when the tie-in between old and new construction starts shedding granules into the gutter, or when the city inspector flags the membrane transition at the shear wall during rough inspection.

Call (626) 606-1081

Which IKO Models This Applies To

IKO’s residential lines break into three tiers, and the part you need depends on which one is already on the main structure. The Cambridge line, IKO’s workhorse architectural shingle, runs 15/32″ thick with a 130 mph wind rating; if your Pomona home was built between 2010 and 2020, odds are this is what’s up there. The Dynasty series, thicker at 19/32″ with a 180 mph rating and the ArmourZone nailing strip, shows up more on custom builds and recent flips near the Phillips Ranch area. The Marathon Plus three-tab, still common on older Pomona stock, uses a different exposure dimension (5-5/8″ versus Cambridge’s 5-3/4″), so a mismatched tie-in looks obvious from the curb and fails faster at the rake edge.

Here’s how to tell without climbing a ladder: check the bundle wrapper in your garage or the photo record from your last roof job. The IKO label prints the series name in the upper right corner, plus a lot code that starts with the plant identifier (Pomona-area shingles usually ship from IKO’s Sumas, Washington plant, code “SU”). For the membrane components, look for the blue StormShield backing or the grey ArmourGard roll - both have the IKO logo and mil thickness printed every 24 inches. We also carry compatible aftermarket equivalents from CertainTeed and Owens Corning when the IKO lead time stretches past your inspection date, though we note the substitution on the written scope so there’s no surprise at final walkthrough.

Signs Your IKO Home Addition or ADU Roof Is Failing

• Granule accumulation in gutters below the addition tie-in. IKO Cambridge sheds some granules in year one, but if you’re scooping handfuls after a normal Pomona Santa Ana wind event, the shingle’s asphalt core is likely baking past its service temperature. The east-facing slopes in Pomona catch morning sun after cool nights, and that thermal cycling hardens the SBS-modified asphalt faster than the warranty table suggests.
• Lifting or cupping at the valley where old roof meets new. This is almost always a fastening issue, not a shingle defect. IKO’s ArmourZone requires six nails per shingle in high-wind zones, and some crews skip the extra two to save time. The result shows up 18-24 months later when the Santa Anas return.
• Water staining on the addition’s ceiling after light rain. If the main roof stays dry but the new space leaks, the failure is likely at the step flashing or the ice-and-water barrier termination. IKO StormShield needs a 4-inch minimum overlap onto the wall sheathing; we’ve found 2-inch laps on Pomona ADUs where the framer rushed the dry-in to beat weather.
• Cracked or brittle membrane at the ADU’s low-slope section. IKO doesn’t manufacture a true low-slope shingle - anything under 2:12 pitch needs a separate membrane system. When a Pomona homeowner or an inexperienced crew tries to extend Cambridge onto a shallow ADU roof, the backwater pooling destroys the fiberglass mat within three to five years.
• Mismatched color between original and replacement shingles, even from the same IKO color name. IKO’s “Harvard Slate” from 2015 isn’t identical to 2024 production; granule sourcing changes with mineral availability. We pull from the same lot when possible, or we re-roof the entire visible slope to avoid the patchwork look that tanks resale value in Pomona’s competitive market.

Before

After

Replacement Cost & What’s Included

The spread on these numbers comes down to what we find when the old roofing comes off. IKO shingles can hide plywood that’s been wet since the last El Niño, and Pomona’s 2023-2024 rain cycle did more damage than most owners realized. Under Clause 1 of the Haven Standard, we put the full price in writing before any tear-off starts - not a “starting at” number that balloons when the sheathing turns to oatmeal. That written scope includes the IKO part numbers, the membrane square footage, the plywood replacement allowance priced per sheet, and the 365-Day Done Right Promise printed on the same page. No signed change order, no additional work - that’s the discipline that’s kept our projects within a few percent of the agreed number across 4,000-plus jobs since 2007.

DIY or Call Us?

There’s a short list of things a Pomona homeowner can safely check from the ground or a sturdy ladder: gutter granule volume, visible shingle lifting at the eaves, and whether the attic access shows daylight where the addition ties in. If you’re comfortable on a ladder and the pitch is walkable, you can also sight down the rake edge for the wavy pattern that signals loose nails.

Everything else belongs to a crew with fall protection, workers’ comp, and a C-39 license. The tie-in between an existing IKO roof and a new addition involves removing the existing shingle course, cutting back the step flashing without damaging the WRB (water-resistive barrier, the house wrap behind your siding), and integrating new StormShield without creating a reverse lap that funnels water into the wall. Get that wrong and you’re not looking at a $400 shingle repair; you’re looking at $8,000 in interior drywall, insulation, and potential mold remediation. We carry the full IKO membrane and shingle inventory on our Pomona warehouse rack, and our crews have tied into more Cambridge and Dynasty roofs than I can count without exaggerating. Measure twice, then we can talk - call (626) 606-1081 and we’ll schedule a free estimate with a written price before anyone touches a shingle.

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