IKO Home Additions & ADU Nationwide

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

IKO-compatible roofing components for home additions and ADU projects in Pasadena typically run $45,000-$130,000 installed, depending on whether you’re tying into existing IKO Cambridge or Dynasty shingles on a 1920s Bungalow Heaven Craftsman or starting fresh on a garage conversion in Madison Heights. We stock IKO ridge caps, starter strips, and underlayment matched to current and recently discontinued color blends, and we carry the full range on our Pasadena-area trucks. Most IKO addition tie-ins we price in writing within 48 hours and start within two weeks of signed approval.

Call (562) 203-4508

Owners usually discover the problem when a permitted ADU or room addition inspector flags a mismatch between existing IKO shingles and new material, or when water stains appear at the addition junction six months after a handyman tied the roofs together without proper IKO-compatible step flashing and Ice & Water Protector.

Which IKO Models This Applies To

IKO’s three residential lines - Cambridge Architectural, Dynasty, and Marathon Plus - each demand specific companion components that are not interchangeable across series. Cambridge uses a heavier-weight ridge cap (37.5 bundles per square coverage) with a distinct shadow band; Dynasty carries a larger exposure and requires Dynasty-specific starter strips to maintain the 130 MPH wind warranty; Marathon Plus, the lighter three-tab line common on 1980s-1990s Pasadena builds, uses standard IKO Leading Edge Plus starters that are still manufactured but increasingly special-ordered.

To identify your existing IKO shingle, check the back of a loose tab or the bundle wrapper if you have attic stock - the series name, color (Pasadena common: Harvard Slate, Weatherwood, Dual Brown), and UL listing date are printed there. If the roof is already installed, measure exposure: Cambridge and Dynasty run 5 7/8 inches, Marathon Plus runs 5 inches exactly. We source OEM IKO components through our distributor in Irwindale; for discontinued Marathon colors we match with IKO-approved aftermarket from Atlas or CertainTeed only when the homeowner signs a wind-warranty acknowledgment. Under Clause 1 of the Haven Standard, that acknowledgment is written, dated, and attached to your scope before any bundle is delivered.

Signs Your IKO Home Addition & ADU Roof Is Failing

• Lifted or cupped shingles at the addition wall junction. This is almost always failed step flashing or missing IKO Ice & Water Protector at the valley, not the shingle itself. Pasadena’s Santa Ana wind cycles accelerate the separation once the sealant strip loses contact.
• Granule loss exposing black asphalt in the first five feet of the new roof section. The IKO starter strip was likely installed backward or a generic starter was substituted, leaving the adhesive edge exposed to UV. We see this on about one in three unpermitted ADU tie-ins in the San Gabriel Valley.
• Interior drywall staining on the shared wall between original house and addition. The IKO ridge vent or cap shingles were not extended fully across the new ridge line, or the original IKO ridge was disturbed without replacing the vent foam. Warm, moist air condenses in the gap.
• Shingle tabs cracking in a diagonal pattern within two years of installation. IKO Cambridge and Dynasty require 6 nails per shingle in high-wind zones; Pasadena sits at the edge of one. Four-nail installation voids the warranty and shows up as systematic cracking along the fastener line.
• Mismatched color banding visible from the street. IKO dyes lots in controlled runs; a contractor who pulled from two different distributor lots or used non-IKO “color match” shingles creates a checkerboard effect that Pasadena’s design review boards notice immediately in historic districts.

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Replacement Cost & What’s Included

The range depends on three factors: whether we’re matching into existing IKO (more labor, precise color lot sourcing) or starting fresh; whether the addition structure requires engineered tie-in to a 1920s rafter tail or a modern truss; and whether Pasadena’s Planning & Community Development Department requires historic compatibility review, which adds 4-8 weeks to permit issuance but does not affect the roofing material cost itself. Every Rowan quote separates materials (IKO bundles, Ice & Water, synthetic underlayment, drip edge by linear foot) from labor, with no change order executed until signed - that’s the discipline that has kept our projects within a few percent of the written price across 4,000 jobs since 2007. The 365-Day Done Right Promise covers installation; IKO’s limited lifetime warranty covers manufacturing defect, and we register it in your name at completion.

DIY or Call Us?

An owner can safely check the attic for active leaks, photograph the shingle exposure and any bundle wrappers in storage, and verify the permit status of the original addition through Pasadena’s online permit portal. What goes wrong fast: walking a 6:12 or steeper pitch to measure, disturbing the existing IKO sealant strip in Pasadena’s afternoon heat, or installing starter strips without the correct 3/4-inch overhang - each of which voids the wind warranty and creates liability if the addition later leaks into the original structure.

We do not recommend DIY on any tie-in involving structural modification, rafter sistering, or valley framing. The load path from new IKO roof to old is where the lawsuits start, and our documented photo record exists partly to show exactly where the connection was made and how. Call (562) 203-4508 to schedule your free estimate; we’ll bring color samples, measure for lot matching, and deliver a written scope with line-item pricing before you decide.

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