Floor Repair in Larkspur

Movement or Damage? The Larkspur Climate Baseline

A repair diagnosis starts with what the climate alone would do to a floor. Using 78,726 hourly readings from Gnoss Field, Novato, a house in Larkspur heated without humidification sits near 40.1% relative humidity in winter, with 15% of heating hours below NWFA's 30% floor, and near 56% in summer — a swing of about 2.6 points in the moisture content of the wood. On white oak that accounts for about 0.022 inch per 2¼-inch strip board and 0.049 inch per 5-inch plank. Gaps inside those figures that follow the seasons are movement. Gaps well beyond them, gaps that stay open through summer, and cupping or crowning are the ones with a cause worth tracing, and the cause is usually moisture from below.

Source: Hourly ASOS dewpoint observations 2015–2025, Iowa Environmental Mesonet (Iowa State University); equilibrium moisture content from USDA Wood Handbook FPL-GTR-190 Eq. 4-5; movement from FPL-GTR-282 Eq. 13-3 and Table 13-5

Finding the Actual Cause

The City's Planning Department lists slope use permits among the development applications it processes.

Regionally, crawl space use in Pacific-division construction has declined long-term and dropped sharply only in the past decade, against 89.9% slab in new 2024 builds — so raised floors turn up more often in Larkspur's 1950s, 1960s, and 1970s stock than in anything recent. We confirm on site.

Raised floors are where most structural floor repair happens: soft spots, squeaks, and bounce that trace back to the subfloor, the joists, or the crawlspace rather than to the finish floor. We go underneath and look. Fixing a soft spot from above without addressing what softened it is a temporary repair sold as a permanent one.

Source: NAHB analysis of the Census Bureau Survey of Construction, foundation type by region (2024)

Larkspur Homes We Work In

Larkspur sits at about 10 feet in Marin County. ACS 2020-2024 5-year estimates put 59.4% of Larkspur's 6,431 housing units in the 1950-1979 range: 23.2% from the 1970s, 23.1% from the 1960s and 13.1% from the 1950s, with a further 9.6% predating 1940. In Larkspur's 1950s, 1960s, and 1970s homes, repairs frequently run into discontinued products and subfloor assemblies that predate current practice. Sourcing a match — or working out where a transition can hide a change of material — is often the harder half of the job.