CGI Home Additions & ADU Nationwide

CGI Home Additions & ADU: The Woodland Hills Owner's Guide

CGI home additions and ADU construction in Woodland Hills typically runs $45,000 – $130,000 installed, depending on square footage, foundation work, and finish level. We stock and install CGI-compatible components across the full addition and ADU build, and our crews can usually be on your property within a few days of your call. Most Woodland Hills homeowners discover they need this work when a city inspector flags an unpermitted structure, when a growing family runs out of room, or when a rental ADU stops meeting current code requirements.

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You’re likely here because you either have a CGI structure showing its age, or you’re planning an addition and want components that won’t fight you two years down the road. Either way, the numbers and compatibility details below will save you time before you ever pick up the phone.

Key Takeaways

• CGI home additions in Woodland Hills: $45,000 – $130,000 full build, with ADU construction running $90,000 – $220,000 depending on kitchen/bath packages
• CGI components are engineered for specific load ratings – mixing in generic framing or incompatible connectors voids most manufacturer specs
• Southern California dry heat and occasional heavy rain cycles put real stress on exterior CGI wall panels and flashing
• We provide written line-item pricing before any work begins, and every crew member arrives with a photo ID badge and uniform you know in advance

Which CGI Models This Applies To

CGI manufactures several product lines that show up regularly in Woodland Hills additions and ADUs: their structural insulated panel (SIP) systems, exterior sheathing and wall panel assemblies, and their pre-engineered window and door opening components. The most common compatibility gotcha we see involves panel thickness – CGI panels come in 4.5-inch and 6.5-inch core depths, and a homeowner who patches with the wrong depth ends up with visible wall offsets at every seam.

To identify what you have, look for the CGI stamp on the panel edge or the manufacturer label inside a door buck or window rough opening. The label will show the panel series, the manufacturing date, and the R-value rating. If the label is gone, we measure panel core depth and check the foam type – EPS core versus polyiso core changes both insulation performance and how we mate new panels to old ones. For OEM parts, we always recommend staying with CGI-spec components rather than generic aftermarket substitutes because the panel interlock profiles are not universal. A panel that looks close at the corner will leak at the first winter rain if the tongue-and-groove geometry is off by a few millimeters.

We also carry and install CGI-compatible window and door headers, base plate connections, and the flashing details CGI specifies for their wall-to-foundation transitions. If your addition will also include cabinetry or countertops, we stock KraftMaid, Cambria, and Silestone as finish options, which means you’re not running to three different suppliers mid-project.

Signs Your CGI Home Additions & ADU Is Failing

• Soft spots or bubbling on exterior wall surfaces. This usually means moisture has gotten behind the CGI panel facing during a heavy rain cycle. Woodland Hills doesn’t see constant rain, but when it comes, failed flashing at window heads or base channels lets water sit against the panel core.
• Visible panel seam separation at corners. CGI panels expand and contract with temperature swings. If the original install used the wrong fastener pattern or the panels weren’t seated fully into their interlock, you’ll see gaps open at the corners first, especially on south-facing walls that catch full afternoon heat.
• Doors or windows that suddenly stick or bind. This points to settlement or a foundation issue under the addition. CGI structures are rigid systems – they transfer movement directly to the opening frames rather than absorbing it like stick framing.
• Musty smell inside the ADU or addition after rain. Water is entering somewhere it shouldn’t. In CGI construction, the biggest culprits are roof-to-wall transition details and unsealed panel joints that were never properly taped.
• Cracked drywall at wall-to-ceiling joints inside the existing house where the addition ties in. The connection point between old framing and CGI panels moves differently. If the tie-in detail wasn’t engineered for differential movement, you’ll see cracking at exactly that transition line.

Replacement Cost & What’s Included

Full CGI home addition work in Woodland Hills lands between $45,000 and $130,000 installed. That range covers a small bedroom or office addition at the lower end up to a larger family room or multi-purpose space at the top. ADU construction runs $90,000 – $220,000 depending on whether you’re building a studio with a kitchenette or a two-bedroom unit with full bath and separate entrance. Garage conversions fall between $30,000 and $80,000.

What moves the price most is foundation and site work. Woodland Hills lots in the hillside areas south of Ventura Boulevard often require pier or caisson foundations, which adds real cost before a single panel goes up. Flat-lot work north of the Boulevard is usually simpler and faster. The written estimate we give you breaks out panels, framing, tie-in work, flashing, and finish by line item – you see the numbers before we touch a wall.

Every job includes our written guarantee, stated plainly: 365 days from the completion date, if something isn’t right, we return and fix it at no cost. No dispute process, no conditions to qualify.

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