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IKO Home Additions & ADU: The Sacramento Owner’s Guide
IKO home additions and ADU projects in Sacramento typically run $45,000 – $130,000 for a full addition, and $90,000 – $220,000 for a detached ADU, depending on square footage, foundation work, and finish level. We install and build IKO-compatible additions and ADUs across Sacramento, and we stock the framing, sheathing, and roofing materials needed to match IKO specifications on most projects. Most homeowners reach out after noticing the signs that their current space isn’t working anymore: a growing family, a home office squeezed into a corner, or an aging parent who needs a place on the property. Trevor Nash and our crew have done everything from kitchen gut-outs in East Sacramento to full ADU builds near McKinley Park, so we’ve seen how these projects unfold in Sacramento’s specific soil and permit environment.
Which IKO Models This Applies To

IKO manufactures roofing and waterproofing products, not the structural framing for additions and ADUs themselves. When a Sacramento homeowner asks us about an “IKO addition,” they’re usually asking about an addition or ADU that will tie into an existing roof system built with IKO shingles or IKO underlayment. Matching the new roof plane to the existing IKO product matters more than most people expect. IKO’s Cambridge and Dynasty shingle lines have slightly different exposure widths and color blends than competitors like GAF or Owens Corning, so if your existing roof is IKO Cambridge in “Harvard Slate,” the new addition needs that same shingle from the same lot if possible. Color lots shift between production runs. We check the existing roof, identify the exact IKO product, and order accordingly so the roofline doesn’t have a visible seam where old meets new. On the ADU side, if you’re building a detached unit with its own roof, you have more flexibility, but matching the main house still looks better for resale in Sacramento neighborhoods like Land Park or Curtis Park.
We’re an independent Sacramento remodeling company. We’re not affiliated with IKO, but we’ve installed enough IKO roofing products to know their specs and compatibility requirements. We also work with KraftMaid cabinetry, Cambria quartz, and Silestone surfaces inside the addition or ADU once the shell is up.
Styles & brands we work with






Signs Your IKO Home Addition or ADU Is Failing
- Roof sag between rafters on the existing structure. This usually points to sheathing rot from years of Sacramento’s wet winters and dry summers. If the underlayment under your IKO shingles is compromised, the new addition’s roof needs a full inspection before we tie in.
- Visible water staining where the existing roof meets a wall or the proposed addition site. IKO underlayment can hold up for years, but flashing failures at roof-to-wall intersections are common in Sacramento homes built in the 1950s through the 1980s. We fix the flashing before framing starts.
- Granule loss on existing IKO shingles. IKO shingles shed granules like any asphalt product, but heavy granule loss near the eaves means the existing roof may be at end of life. Tying a new addition into a failing roof doubles your cost later. We’d rather tell you now.
- Foundation cracks or settling in the area where the addition will go. Sacramento’s clay soil expands and contracts with moisture. If your existing foundation shows stair-step cracks, the new addition’s foundation needs engineered design, not just a standard pour.
- Uneven floors in the existing structure. An addition ties into the existing framing. If the main house has floor deflection issues from settling or water damage, we address that before we frame the new space. Otherwise the new floor just follows the old dip.
See the difference
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AfterReplacement Cost & What’s Included

A home addition in Sacramento runs $45,000 – $130,000 depending on square footage, whether you’re adding a single room or multiple, and the finish level. A detached ADU runs $90,000 – $220,000, with the range driven by site work, utility connections, foundation type, and whether you’re building a 400-square-foot studio or a full two-bedroom unit. Garage conversions in Sacramento typically land between $30,000 and $80,000 depending on the condition of the existing slab and whether new plumbing or electrical service is needed.
Every Penhallow Remodeling project gets a written price before any work starts. You’ll see the line items: demo, foundation, framing, roofing materials that match your existing IKO product, electrical, plumbing, drywall, flooring, paint, and the finish work. The number on day one is the number on the invoice. We back every addition and ADU with our 365-Day Done Right Promise, which says plainly: if it’s not done right, we make it right. In writing. Free.
DIY or Call Us?
You can do some of the thinking yourself. Measure your lot setbacks, check Sacramento County’s ADU size limits, and sketch what you actually need the room to feel like. That saves time at the first meeting. But the building part? Framing an addition or ADU involves structural engineering, electrical service, plumbing rough-in, and roofing tie-ins that have to be done to code. A bad tie-in between new framing and an existing IKO roof leaks in the first Sacramento rain, and by then the drywall is up and the repair costs triple. The danger isn’t acute like a high-tension garage spring, but it’s real: a six-figure room that fails inspection or rots from the inside out is expensive in slow motion.
We handle permits, engineering, and the build so you don’t have to be the one standing in front of a city inspector explaining why the rafter spacing doesn’t match the plan. Call (279) 300-1177 if you want a real price and a real schedule. Trevor will tell you what the room should cost, not what a salesperson thinks you’ll pay.
FAQs

A properly framed addition or ADU with an IKO roof system should last 40 to 60 years before major structural work, though the IKO shingles themselves typically run 20 to 30 years in Sacramento’s sun exposure before they need replacement. The framing and foundation, done right, outlive the roof covering.
Yes, in many Sacramento cases we can repair specific failures: roof tie-in leaks, foundation settling, dry rot in wall framing, or underlayment replacement under existing IKO shingles. Repair is always the cheaper first step if the structure is fundamentally sound. Call (279) 300-1177 and we’ll take a look before recommending anything.
A typical Sacramento addition takes 3 to 5 months from permit approval to final inspection. A detached ADU usually runs 4 to 8 months depending on utility work and site conditions. You’ll get a written timeline with your written price, and we show up in the window we gave you.
We keep common IKO Cambridge and Dynasty colors on order rotation for Sacramento projects, and we can source specific IKO products from our local suppliers within a few days. If your existing roof is an older IKO product that’s been discontinued, we’ll match the closest current product and tell you exactly how it differs before we order.
Call (279) 300-1177 to schedule your free estimate. A real person answers, day or night.
Written by Trevor Nash, Owner, Penhallow Remodeling Sacramento at Penhallow Remodeling Sacramento, serving Sacramento and nearby areas.


