Built to outlast
the trend.
KEYSTONE is a premium design-build contractor serving the San Francisco Bay Area. We build custom homes, whole-home renovations, and commercial interiors that hold their value, their character, and their structural integrity for decades.
Services
Custom Homes
Ground-up custom residences designed for the site and the life you intend to live in them.
Learn moreWhole-Home Renovation
Every system, every surface — a full renovation delivered as a single coordinated project.
Learn moreDesign-Build
Architecture and construction under one roof — one fee, one schedule, zero blame-shifting.
Learn moreCommercial Fit-Out
Tenant improvements and commercial interiors delivered on compressed schedules without the war stories.
Learn moreAdditions & ADUs
Expand your footprint without compromising the original structure — or your daily routine.
Learn moreFeatured Projects
Ridgeline Residence
A sculpted hillside home that disappears into the oak canopy — post-and-beam structure, rammed-earth retaining walls, and floor-to-ceiling glazing aligned to the winter solstice sunrise.
Ashford Capital Partners HQ
A full-floor tenant improvement for a private-equity firm — exposed concrete ceilings, walnut millwork, a partner suite with sound-rated glass pivots, and a client boardroom designed to win deals.
Laurel Avenue Renovation
A 1928 Craftsman bungalow brought to net-zero with a seismic soft-story retrofit, a rear addition, and a kitchen that won a 2023 NKBA award — all while preserving every original fir floor.
The Five-Phase Build
Discovery
We learn your site, program, and budget before we write a single spec. This 2–4 week phase is free — because it's the only way to give you an honest number.
Design
Our design director produces concept drawings, section cuts, and material boards. You see what it looks like before we lock the scope.
Pre-Construction
Permit filing, subcontractor bidding, MEP coordination modeling, and a detailed construction schedule. No surprises when the shovel turns.
Build
Your dedicated superintendent on-site every day. Weekly owner's reports, daily photo logs, real-time budget tracking.
Handover
A walk-through punchlist, a complete close-out binder, and a 10-year structural warranty. The relationship doesn't end at ribbon-cutting.
Built on three non-negotiables.
Craftsmanship that shows
We write detailed specifications before we ever send a subcontractor to bid. Our trade partners know exactly what's expected — and our field team enforces it at every rough inspection, not just the final walkthrough.
Schedules that hold
97% of our projects close on the contracted date or earlier. We build and maintain a detailed CPM schedule from pre-construction through handover, updated weekly and shared with every client in plain language.
Budgets that close
Our estimating database spans 15 years and 240+ projects. We don't give you a round number and hope — we give you a line-item budget with a documented allowance strategy and a written contingency plan.
The verdict, in their words.
KEYSTONE handed over our renovation 11 days early. I've never seen that in 30 years of project work. And the quality — I walked the punchlist expecting pages. It was four items.
What sets them apart isn't the craftsmanship — it's the communication. We had a weekly call with Marcus, a daily photo log, and a real-time budget dashboard. Zero surprises, from permit to keys.
I've collaborated with six contractors on hillside residential. KEYSTONE is the only team I've worked with that read the structural drawings before the first site visit. That level of rigor shows in the finished work.
Ready to build something that lasts?
Tell us about your project. We'll respond within one business day with an honest assessment of scope, timeline, and budget.