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Cover Home Additions & ADU: The Woodland Hills Owner’s Guide
A full Cover home addition or ADU project in Woodland Hills typically runs $45,000 to $130,000, with ADU construction starting around $90,000 and garage conversions landing between $30,000 and $80,000. We price every job in writing before any work starts, so you know the number up front and it does not change on you later. Most homeowners reach out to us when an earlier contractor’s work has failed, when plans drawn years ago no longer meet current Los Angeles building codes, or when they realize a cheaper bid left them with an unpermitted structure that can’t be financed or insured.
We’re an independent remodeling company, not affiliated with Cover. What we do is match Cover-style home addition and ADU plans to real-world Woodland Hills site conditions, handle the permitting, and build it so it lasts through valley heat, Santa Ana winds, and the occasional heavy rain season.
Which Cover Models This Applies To
Cover is a design-and-build prefab company that produces accessory dwelling units and small home additions using a modular panel system. Their catalog includes studio ADUs, one-bedroom and two-bedroom units, and compact home additions meant to attach to an existing single-family house. The compatibility question that matters most in Woodland Hills is not which Cover model you have, it’s whether your site and foundation can actually accept it. Hillside lots, expansive clay soil, and older post-and-beam foundations common in neighborhoods south of Ventura Boulevard all change what can be built and what it costs.
If you already have Cover plans or a partially installed Cover structure, we can work from those drawings or match measurements to the correct panel and connection specifications. Where it makes sense, we use OEM Cover components. Where it doesn’t, we recommend specification-grade aftermarket materials from partners like KraftMaid, Cambria, and Silestone for interior finishes, with framing and structural work done by our own crews to current California Title 24 energy standards and Los Angeles Department of Building and Safety requirements.
Styles & brands we work with
Signs Your Cover Home Additions & ADU Is Failing
- Cracks at wall-to-ceiling joints or corner seams. Modular panel systems move with temperature swings. In Woodland Hills, where summer days hit the high 90s and nights drop into the 50s, expansion and contraction is constant. Cracks wider than a quarter inch usually mean the panel connections were under-tightened or the foundation has shifted.
- Doors or windows that stick or won’t latch. When a prefab addition settles unevenly, the first place it shows is at door and window frames. If you have to shoulder the door open, the structure is out of square, not the hinge.
- Moisture staining or soft spots at the roofline or base plates. The hills and canyons around Woodland Hills get more rain than people expect, and a poorly flashed panel joint will let water in long before you see it on interior drywall. By the time paint bubbles, the framing behind it is already compromised.
- Visible gaps where the addition meets the main house. Attached additions require proper seismic ties between old and new structures. A widening gap at that connection line is a structural warning, not a caulk problem.
- Floor bounce or a noticeable slope. If a corner of the unit feels soft underfoot or a marble rolls across the floor on its own, the foundation or floor framing was undersized for the soil conditions. In parts of Woodland Hills with adobe clay, this is a known issue that proper soil testing catches up front.
See the difference
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AfterReplacement Cost & What’s Included
For a Cover home addition in Woodland Hills, expect $45,000 to $130,000 depending on size, site access, foundation work, and interior finish level. A standalone ADU runs $90,000 to $220,000 once you factor in utility connections, solar requirements, and kitchen and bath build-out. Garage conversions are the most flexible, landing between $30,000 and $80,000. The spread comes down to three things: how much grading or foundation repair the site needs, whether your panel package is intact or needs replacement sections, and the finish materials. Cheaper numbers usually mean no permits, no soil report, and no warranty. Our written price includes permits, site prep, structural work, rough and finish construction, and a written guarantee covering 365 days from the completion date. If something fails within that year, we return and fix it at no charge.
DIY or Call Us?
A prefab addition is not a weekend project. These are engineered structures with seismic, electrical, plumbing, and Title 24 energy requirements, and the work requires a licensed contractor and city inspections. What you can do yourself is document the problem: photograph cracks with a tape measure for scale, mark where doors bind, check whether gaps change between morning and evening. That information helps us price the fix accurately. What you should not do is open up walls or try to re-tension panel connections. You’ll void any remaining warranty and create a bigger repair. If what you have is not working, call us at (831) 290-6866. We’ll look at what is there, tell you straight what it costs to make it right, and write the price down before anything starts.
FAQs
A properly installed modular addition should last 50 years or more on the structural frame, with roofing, windows, and exterior seals needing replacement every 15 to 25 years depending on sun exposure. In Woodland Hills, west-facing walls take heavy afternoon UV, which shortens exterior finish life compared to coastal areas.
Yes, in most cases. Panel connections can be re-tensioned, flashing replaced, and foundation piers added under settled corners. Full replacement is only necessary when water intrusion has rotted structural members or the original install never met code in the first place. Call (831) 290-6866 and we’ll give you an honest read on which situation you’re in.
A garage conversion typically takes 10 to 14 weeks. A new ADU runs 4 to 7 months including permitting. A home addition ranges from 3 to 6 months depending on scope and inspection scheduling with the Los Angeles Department of Building and Safety. We’ll put the timeline in your written price before work begins.
We can work from Cover drawings, match panel specs, and source OEM components where available. For finish materials, we install specification-grade lines including KraftMaid cabinetry, Cambria and Silestone surfaces, along with the structural and MEP work handled by our own verified crews. Estimates are free, and the price is written before any tool leaves the truck.
Written by Isaac Pruett, Owner, Mason Remodeling Co – Woodland Hills, CA at Mason Remodeling Co Woodland Hills, serving Woodland Hills and nearby areas.
