Cover ADU in Sunnyvale, CA | Fielding ADU San Jose
We’re an independent Room Addition Contractor in Sunnyvale that services and installs Cover prefab ADUs on the post-war ranch lots that dominate this city. Our crews work on Cover S Series, M Series, Accessory Units, and panelized builds without being tied to the manufacturer, so we diagnose and fix what’s actually failing. What makes our Cover work different in Sunnyvale is simple: we know the orchard soil, the old 100A panels, and the permit shortcuts that trip up other contractors. Call (669) 201-3984 for a free estimate.
Why Sunnyvale Residents Choose Us for Cover Service
We’ve been building to The Garrison Standard since 2006, and that means a written price before any work starts, a written one-year guarantee on every job, and a crew you can identify the moment they arrive. Reed Calloway, our owner, learned construction at LA Trade-Tech and spent two decades on ground-up residential builds across California before settling into Sunnyvale’s ranch-lot landscape. He runs our Cover sales & service work the same way he ran framing crews: short sentences, fixed prices, and a schedule that doesn’t slide.
Sunnyvale homeowners call us after a bad contractor experience. They want someone who shows up on the window we gave them, puts the price in writing, pulls the permit the right way, and leaves the site clean. That’s The Garrison Code: show up, price in writing, by the book, leave it clean, stand behind it for a year. We use Cover-specified OEM panels and connectors for structural work, and we’re direct when an aftermarket HVAC or electrical part makes more sense than waiting six weeks on a factory lead time.
Common Cover ADU Problems We Solve in Sunnyvale
- Seismic shear-wall attachment gaps. Cover panelized modules meet the foundation at anchor points that older Sunnyvale slabs simply don’t have. Homes built in the 1950s and 1960s south of El Camino Real rarely had modern anchor bolts or hold-downs, so the panel-to-foundation connection can work loose over time. We inspect, retrofit anchors, and re-secure the shear-wall path to meet Santa Clara County seismic code.
- Undersized 100A service tripping. This is the most common service call we get in Sunnyvale’s post-war tracts. The original 1950s ranch house still has a 100A panel, the Cover unit’s split-system heat pump draws 30A on startup, the tenant runs a dryer or space heater, and the whole ADU goes dark. The fix is usually a dedicated 200A subpanel, not a Cover defect.
- Roof-flashing leaks at module marriage lines. Sunnyvale’s winter rains hit low-slope parapet roofs hard, especially on Cover units where two modules meet. The flashing detail at that seam is the first place water finds a path. We re-flash, re-seal, and test with a water hose before we call it done.
- Drywall cracking at interior panel seams. Much of Sunnyvale’s original orchard land has expansive clay sections that shrink and swell with seasonal moisture. A Cover unit set on a slab over that soil will show hairline cracks at panel seams within the first two years. We assess whether it’s cosmetic settlement or a foundation issue needing attention.
- Orchard irrigation lines under the foundation pad. Old Sunnyvale lots south of El Camino Real frequently have buried orchard irrigation pipe that the permit drawings didn’t account for. When a Cover unit’s foundation is set over a decaying line, you get voids, settling, and uneven slab support. We trench, remove the old pipe, re-compact, and re-grade before the unit ever gets placed.
Cover Service in Sunnyvale: What Local Conditions Mean for Your Equipment
Here’s what you won’t read on a generic Cover page. Sunnyvale’s pre-approved “Sunnyvale Standard” detached ADU plans assume a flat, compacted rear yard, because the city designed those plans to speed up permitting on its many 1950s-70s ranch lots. But many original lots south of El Camino Real, near Sunnyvale Avenue, were once apricot and walnut orchards. The irrigation lines are still down there. The soil was never mechanically compacted for a structure. We regularly find Cover unit foundations on those lots needing additional grading and trenching that the permit drawings didn’t predict. A contractor who only reads the pre-approved plan gets a surprise after excavation begins. We expect it, because we’ve seen it on block after block in this part of Sunnyvale.
On a street off Sunnyvale Avenue just south of El Camino Real, our crew was called to a 2022 Cover S Series unit where the tenant’s bedroom breaker kept tripping. We traced it to the original 100A panel shared with a 1958 ranch house. The Cover unit’s heat pump and a portable space heater were pulling 47A on a 30A subfeed. We installed a dedicated 200A panel upgrade and re-fed the ADU. The unit passed final inspection the next week.
Cover Models & Products We Service in Sunnyvale
We work on the full Cover line: S Series factory-built detached units in one and two-bedroom configurations, M Series modular units with the wider footprint, compact Accessory Unit studios, and Custom Panels that get site-assembled. As a Garage Conversion Contractor - Sunnyvale homeowners trust, we also understand how to adapt existing structures. For structural repairs, we use Cover-specified OEM panels and connectors. For HVAC, electrical, and plumbing components, we’ll often substitute quality aftermarket parts when factory lead times would delay a tenant’s move-in. We’re upfront about the tradeoff and never make that call without your sign-off. What we stock locally for fast Sunnyvale turnaround: common panel connectors, shear-wall retrofit hardware, breakers for 200A upgrades, and flashing materials for module seam repair.
Cover Service Pricing in Sunnyvale
What you’ll pay depends on what’s actually wrong. A roof-flashing reseal at a module marriage line runs $450 to $900. Electrical panel upgrades for adding a Cover ADU to an existing Sunnyvale home typically run $3,500 to $6,500, depending on whether we’re adding a subpanel or replacing the main service. Foundation re-grading and trenching on orchard lots starts around $2,000 and goes up from there based on what we find underground. A permitting fix for shear-wall anchor retrofits typically lands between $1,800 and $4,000. Every estimate is free, written, and line-itemed. The number you approve is the number on the final invoice. Call (669) 201-3984 and we’ll walk the site with you, no charge.
Serving Sunnyvale, CA - Our Local Coverage Area
We’re based in the Sunnyvale area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs – Cover ADU in Sunnyvale
Can you fix a Cover ADU where the roof leaks at the module seam after Sunnyvale’s winter rains?
Yes. This is a flashing failure at the marriage line, not a structural problem. We remove the old flashing, re-detail the seam, re-seal it, and water-test it. Most repairs are done in a single visit. Call (669) 201-3984 to schedule an inspection before the next storm cycle.
Do you replace Cover ADU exterior wall panels that crack from foundation settlement on old Sunnyvale orchard soil?
We do. We’ll first determine whether the crack is from panel movement or from foundation settling below the panel. If the slab is sound, we replace the affected panel with a Cover-specified OEM match and re-secure the connection points. If the foundation is moving, we address that first. Call (669) 201-3984 for a site assessment.
Our Cover ADU trips the main breaker when we run the heat pump and dryer. Is that a Cover issue or an electrical panel issue?
In Sunnyvale’s post-war homes, it’s almost always the panel. A 1950s-70s era 100A service feeding both the original house and a Cover unit’s split-system heat pump is undersized for that combined load. The fix is a dedicated panel upgrade, not a Cover repair. We’ll do a load calculation first, then give you a written price. Call (669) 201-3984 for a free electrical assessment.
Can you install a Cover Prefab ADU on a Sunnyvale lot that has an old walnut tree stump in the rear yard?
Yes. We remove the stump, excavate the old root ball, re-compact the soil, and pour a foundation pad that meets shear and settlement requirements before the Cover unit arrives. This is one of the most common site-prep jobs we do south of El Camino Real. Estimates are free. Call (669) 201-3984.
Do you handle Title 24 ventilation requirements for Cover ADUs in Sunnyvale’s mild climate?
We do. Sunnyvale’s climate means heating is required but air conditioning is optional, so Title 24 compliance here is usually a matter of proper venting, insulation levels, and the right heat pump sizing. We verify the Cover unit’s pre-engineered envelope meets current code and address any ventilation gaps before final inspection. Call (669) 201-3984 if you need a Title 24 review on a unit installed by another contractor.
Service Areas Near Sunnyvale
We serve Sunnyvale and the surrounding Santa Clara County communities, including Sunnyvale service area coverage for full-scope ADU work. Need a comparison for your search? Check our Cover service in Campbell page for that market’s specifics, or Cover service in San Jose for the larger metro context. We also field calls from Menlo Park, Saratoga, and Cupertino homeowners.
Book Your Cover Service in Sunnyvale Today
Put it in writing, show up on time, build it right. That’s how we run Cover work in Sunnyvale. Call (669) 201-3984 for a free estimate and a written line-item price before any work begins. A live person answers, day or night.
Written by Reed Calloway, Owner at Fielding ADU San Jose, serving Sunnyvale since 2006.
