Lic #1007864 · San Mateo County · General Contracting
Custom ADU & Additions
Detached ADUs, room additions, garage conversions, and JADUs — permitted, engineered, and built to estate standards.
America's most exclusive zip code. Discreet, white-glove contracting for ultra-luxury estates and legacy Peninsula properties.
California's ADU laws have unlocked enormous property value, and JMG builds accessory dwelling units and home additions that match the main residence — not prefab afterthoughts. From Los Altos to San Ramon, our ADUs and additions command premium rents and appraisals.
In Atherton and across San Mateo County, JMG delivers adus & additions under California Contractor's License #1007864 — permitted, inspected, and personally overseen by owner Jerry Guinn. We manage the entire lifecycle: feasibility, design, permitting, utilities, and construction, delivering turnkey units and seamless additions ready for family or income.
Atherton builds answer to the Town's Building Department on Station Lane — and to the heritage-tree ordinance that shapes where additions, ADUs, and driveways can land on the town's one-acre estate lots. We plan around protected oaks, manage design review, and deliver the discreet, high-touch project management Lindenwood and West Atherton estates expect.
What's included in Atherton
Recent adus & additions work
The process in Atherton
Private Consultation
Walk the property with owner Jerry Guinn. Honest scope, realistic timeline, and a written line-item estimate — free.
Design & 3D Rendering
See the finished project in photorealistic 3D before a single wall comes down. Finishes get locked before demo day.
Permits, Handled
Plans, submittals, corrections, and city or county coordination under CA License #1007864. You sign — we run the process.
Build & Final Inspection
Sixteen in-house trades on one schedule, one accountable owner. Inspection passed, walkthrough done, keys in hand.
ADUs & Additions in Atherton — FAQ
Feasibility check on your lot, design and 3D rendering, permit submittal, then construction. State law guarantees most ADUs a 60-day ministerial review — we prepare complete packages so that clock never stops.
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ADUs & Additions · Atherton