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Owens Corning Home Additions & ADU: The Long Beach Owner’s Guide
If you’re planning an Owens Corning home addition or ADU in Long Beach, you’re looking at $45,000 to $130,000 for a full home addition, with ADU construction running $90,000 to $220,000. Sawyer Remodel Long Beach installs and builds Owens Corning-backed additions and ADUs throughout Long Beach, from Naples to Bixby Knolls. We’re an independent contractor, not affiliated with Owens Corning, but we spec their materials because they hold up to coastal air better than most.
We usually hear from Long Beach owners two ways: they’ve got a garage or underused space and want to know if it can become a livable ADU, or they’ve outgrown their floor plan and need a real addition. Either way, the first question is always the same: what will it cost, in writing, before a single tool gets picked up. That’s how we work.
Which Owens Corning Materials This Applies To
Owens Corning’s role in home additions and ADUs in Long Beach comes down to insulation, roofing, and weather barriers. For additions, we typically spec Owens Corning EcoTouch or Thermafiber insulation depending on the wall assembly. For ADU roofs, Owens Corning Duration shingles are the standard pick because their SureNail strip handles the wind gusts that come off the Pacific. The compatibility gotcha most owners don’t know: Owens Corning Duration shingles require their specific underlayment system to maintain the manufacturer warranty. Skip it, and that 50-year shingle warranty quietly disappears.
For Long Beach specifically, we also deal with Title 24 energy requirements, which means insulation R-values matter more here than in, say, Arizona. Owens Corning’s R-13 and R-21 batt products fit standard 2×4 and 2×6 framing, which covers most ADU wall assemblies. If you’re converting a garage, the floor insulation spec is often R-10 rigid board, and Owens Corning’s FOAMULAR product is the one we cut to fit slab edges. Not all rigid board is rated for ground contact; FOAMULAR is, and that’s the kind of detail that keeps a Long Beach ADU floor dry during winter rains.
Styles & brands we work with
Signs Your Home Addition or ADU Project Is Being Done Wrong
You won’t see an Owens Corning product “fail” the way a water heater fails. But you’ll see the results of bad installation. Here’s what we find when we get called to fix someone else’s work in Long Beach:
- Insulation batts sagging or falling out of the wall cavity. This means the installer used staples alone instead of friction-fit plus batt supports. Sagging insulation leaves air gaps, which means your energy bill climbs and your walls sweat. In Long Beach’s marine layer, that sweat becomes mold inside the cavity.
- Roof felt showing through the shingle gaps. That’s a sign the shingles were installed without the Owens Corning underlayment system we mentioned earlier, or the rows weren’t properly staggered. Water gets in, and the roof deck rots before you see a leak on the ceiling.
- Cold spots on the floor of a garage conversion. If the slab edge wasn’t insulated with rigid board, cold air migrates in from the exposed foundation. This is the most common miss in Long Beach garage-to-ADU flips.
- Attic temperatures twenty degrees hotter than outside during summer. Poorly vented roof assemblies bake the Owens Corning shingles from underneath, which breaks down the asphalt matrix years before the warranty says it should.
- Drafty corners where the addition meets the original house. That seam needs a continuous air barrier, and too many crews skip it. Air leaks there mean your Owens Corning insulation is working at half capacity.
See the difference
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After
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AfterReplacement Cost & What’s Included
Home additions in Long Beach run $45,000 to $130,000, depending on square footage, foundation work, and whether you’re adding a kitchen or bath. ADU construction lands between $90,000 and $220,000, with garage conversions on the lower end at $30,000 to $80,000. These ranges assume Owens Corning insulation and roofing where applicable, plus standard Long Beach permit fees.
What drives the range: soil conditions (some Long Beach lots need deeper footings), whether your existing panel has capacity for a new subpanel, and how much of the existing roof ties into the new roof line. Every estimate we give is a written line-item price, not a ballpark. You approve the number, and that’s the number. If we find something unexpected behind a wall, we stop, show you photos, and get a written change order before proceeding. No surprises at the invoice.
Our work carries the 365-Day Done Right Promise: if something’s not right within a year, we fix it. In writing, every time.
DIY or Call Us?
You can handle the planning phase yourself: measuring rooms, pulling property records from the City of Long Beach, maybe sketching a rough ADU layout. But the second you’re cutting into roof sheathing or framing a knee wall, you’re in territory where a mistake costs five figures to undo. Luca Romano has spent nearly two decades doing this work across Long Beach, and he’ll tell you the same thing: framing that’s off by half an inch turns into a roof line you can see from the street.
The work tells you everything. The rest is just talking.
If you want a crew that shows up when they say they will, leaves the job site clean, and puts the price in writing before anything gets cut, call (562) 512-6480. We’ll walk the site with you and give you a real number.
FAQs
Most home additions in Long Beach take 3 to 6 months from permit approval to final inspection, and ADUs typically run 4 to 8 months. Permit review with the City of Long Beach adds 4 to 12 weeks depending on the project scope. Call (562) 512-6480 for a timeline based on your specific property.
Yes, if the framing is sound and only the insulation, roofing, or weather barrier needs replacement, we can typically fix it. The question is whether the existing foundation meets current Long Beach code for the use you want. We’ll tell you honestly which makes more sense before you spend a dollar on design.
We keep standard Owens Corning batt insulation, FOAMULAR rigid board, and Duration shingle starter rolls on hand for most Long Beach jobs. Special-order items like Thermafiber fire-rated batts or specific underlayment systems usually arrive within a week through our supplier network.
Only if we find something that genuinely changes the scope, and you’ll approve any change in writing before we move forward. We don’t do surprise invoices. If it’s discovered during framing that your foundation needs additional work, you’ll see the line item, the reason, and the cost before we touch it.
Written by Luca Romano, Owner, Sawyer Remodel Long Beach at Sawyer Remodel Long Beach, serving Long Beach and nearby areas. Raised in Los Angeles and trained at Los Angeles Trade-Technical College, Luca has spent the better part of two decades building additions, ADUs, and kitchen overhauls across Long Beach, from Belmont Shore to the streets around the Queen Mary.
