A Roof Built to Outlast the Valley Heat—Backed by Precision Diagnostics
Most roofing "estimates" are just a guy on a ladder with a tape measure. They guess at the wood rot, they guess at the flashing, and they hope your roof-mounted AC unit doesn't leak after they leave. When they’re wrong, you pay for it in change orders and mid-project surprises.
At Grandmark Service Company, we don’t guess—we verify. We are the only Roofing contractor using Advanced Sub-Surface Diagnostics to see through your existing layers before we even tear off a single shingle.
We'll Install The Perfect Roof Your Home
Shingles
Stop leaks where they start. We specialize in shingle roofing that flawlessly accommodates your HVAC and solar setups.
Tile
Don't let hidden vulnerabilities compromise your estate. We execute flawless tile installations using architectural-grade materials engineered to last.
Precision Installs. Zero Surprises. Hear From Our Clients
Proven Precision Across the Central Valley
Explore our portfolio of diagnostic-backed roofing and HVAC projects. See how we are protecting investments and delivering lifetime value in your neighborhood.
SERVICE AREAS
Proudly Serving the Central Valley & Beyond
North Valley & Capital Region
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Sacramento
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Stockton
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Modesto
Central Valley (Headquarters):
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Fresno
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Clovis
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Visalia
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Merced
South Valley:
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Bakersfield
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Tulare
Frequently Asked Questions
Most contractors push for full replacements based on visual guesswork. We do things differently. We use sub-surface diagnostics to evaluate the true condition of your decking and underlayment. If your core structure is failing, a replacement is the only way to protect your home. We provide the visual proof so you know exactly why a new roof is the right investment, eliminating any doubt.