Hardwood Flooring in Larkspur

Measured Humidity and Solid Wood Movement in Larkspur

Gnoss Field, Novato, 14 miles from Larkspur and at about the same elevation, supplied the 78,726 hourly dewpoint readings, 2015 to 2025, behind these figures. Warm that winter air to 70°F without adding moisture and it settles at a median 40.1% relative humidity, with 15% of heating-season hours below the 30% floor NWFA sets for wood floors; the same air reaches 56% in summer. Solid hardwood follows those numbers: its equilibrium moisture content runs from about 7.7% in the heating season to 10.3% in summer, and on the Forest Products Laboratory's coefficients for American white oak that swing changes the width of a 5-inch plainsawn board by about 0.049 inch (about 1/20 inch) — against 0.025 inch for the same board quartersawn. That is a mild climate for solid wood, and it is why wider plank is a realistic choice in Larkspur rather than a gamble.

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

Subfloor and Foundation Work

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.

Over a crawlspace, solid hardwood is in its element — plank or plywood subfloors take fasteners well — but only when the crawlspace itself is dry. We check the ground cover, look for standing water and rot at the joist ends, and read the moisture content of the subfloor from below. Cupping in a solid floor is almost always a crawlspace problem that surfaced upstairs.

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. Larkspur's 1950s, 1960s, and 1970s stock is directly relevant here, because homes of that period frequently have a board or plywood subfloor that will hold a nail-down installation, and sometimes original wood still under the carpet. We check for both before quoting a full replacement — refinishing what's already there is often the better answer.