IKO Home Additions & ADU Nationwide

IKO Home Additions & ADU: The San Diego Owner’s Guide

IKO-compatible roofing and waterproofing components for home additions and ADU projects in San Diego typically run $53,100-$153,400 installed, depending on whether you’re tying into an existing IKO Cambridge or Dynasty roof system or building a standalone ADU envelope from the sheathing up. We stock IKO Ice & Water Protector, synthetic underlayment, and starter strip inventory matched to local code requirements, and we can usually spec and order same-day for active projects. Most San Diego homeowners discover an IKO component issue during an addition tie-in, when the new roof plane meets the existing IKO shingles and the step flashing or counter-flinging detail doesn’t seat properly against the older shingle profile.

Call (858) 434-8926

Which IKO Models This Applies To

IKO’s residential lines fall into three tiers that behave differently during addition and ADU work. The Cambridge architectural laminate, Dynasty performance laminate with ArmourZone, and Marathon Plus 3-Tab are the systems we encounter most in San Diego County. Cambridge uses a standard 5 7/8″ exposure; Dynasty runs slightly larger at 6 1/4″ with a reinforced nailing zone. The critical compatibility point is the starter strip: IKO’s Leading Edge Plus must pair with the matching shingle line, or the first course won’t seal correctly along the eave, and San Diego’s Santa Ana wind events will find that gap.

To identify what you have, check the shingle back for the IKO stamp and lot number, or measure the exposure from butt edge to butt edge on the roof plane. For additions, we also verify the existing IKO Ice & Water Protector membrane thickness, 1.5 mm versus 2.0 mm, because California Title 24 energy code and local amendments in San Diego require specific permeability ratings at the valley and penetration details. We are an independent contractor, not affiliated with IKO. We source OEM IKO materials and quality aftermarket equivalents from Atlas and Malarkey when the project timeline or budget calls for it, and we document the substitution in writing before it goes on the roof.

Signs Your IKO Home Additions & ADU Is Failing

• Lifted starter course along the addition tie-in. IKO’s self-seal adhesive strip can de-bond if the existing roof deck temperature was below 40°F during the original install, or if dust from the framing phase contaminated the seal surface. In San Diego’s coastal zones, morning marine layer moisture slows cure time.
• Valley leaks where old IKO meets new construction. The woven or closed-cut valley detail depends on consistent shingle thickness; mixing IKO Cambridge with a heavier competitor shingle in the addition creates a water funnel, not a watershed.
• Granule loss exposing the fiberglass mat on IKO Dynasty in the first five years. This is premature. Dynasty’s ceramic granule coating should hold 20-plus years. If you’re seeing bald patches, the lot may have had a manufacturing adhesive issue, or the attic ventilation below is insufficient for the San Diego solar heat gain.
• Ice & Water Protector bubbling at wall abutments. The membrane needs a smooth, clean substrate. Rough-sawn sheathing or OSB with raised edges traps air that expands in our inland heat; the bubble lifts the membrane off the nail line.
• Step flashing corrosion behind stucco at the addition junction. IKO’s system relies on proper counter-flashing height, 4 inches minimum. Stucco crews sometimes bury the top leg too shallow, and San Diego’s salt air accelerates the galvanic breakdown on non-stainless metals.

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Replacement Cost & What’s Included

For a full home addition roof tie-in or standalone ADU envelope using IKO materials in San Diego, our installed range is $53,100-$153,400. That spread reflects square footage, deck condition, and whether we’re matching an existing IKO color that’s been discontinued. A typical 400-square-foot ADU roof with IKO Cambridge, full tear-off, 1/2″ plywood replacement where needed, Ice & Water Protector at valleys and penetrations, ridge vent, and aluminum drip edge runs toward the lower third of that range.

What drives the number up: structural deck repair from prior leaks, crane rental for tight San Diego infill lots, or upgrading to IKO Dynasty for the enhanced wind warranty. Every quote is flat and written before work starts, per Clause 1 of the Haven Standard. The price includes labor, materials, permit pulling, inspection scheduling, and our documented photo record. We warranty the workmanship for 365 days under the Done Right Promise. Call (858) 434-8926 for a written estimate.

DIY or Call Us?

There’s a safe middle ground here. A homeowner can walk the roof with binoculars and spot the symptoms above, and you can check the attic for water staining at the addition junction without risk. But once you’re removing IKO shingles to expose the deck, you’re working on a sloped surface at height, and the tear-off generates debris that damages the new work below if not contained. The self-seal adhesive on IKO’s starter strips activates with hand pressure and body heat; in San Diego’s afternoon sun, they get tacky fast and unforgiving to reposition.

More critically, the tie-in between existing and new construction is where water goes when it’s done wrong. We’ve redone three in the past two years where the DIY addition looked fine from the ground but funneled water behind the stucco during the first winter storm. Measure twice, document once, then we can talk price. For the actual install, call (858) 434-8926.

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