Floor Refinishing in Larkspur

Seasonal Gaps in Larkspur Floors, by the Numbers

Seasonal gaps between boards are a common reason people ask about refinishing, and Larkspur's measured climate shows how much of that gapping is simply the wood moving with the seasons. Measured at Gnoss Field, Novato, then brought to 70°F, the air averages 40.1% relative humidity over the heating season and 56% over summer, which settles wood at roughly 7.7% and 10.3% moisture content. For a traditional 2¼-inch oak strip floor that is about 0.022 inch of seasonal shrinkage per board (about 1/45 inch); for 5-inch plank, about 0.049 inch. Gaps in that range that open in winter and close by summer should not be filled — filler packed into a winter gap gets crushed out, or pushes the boards toward cupping, once the wood takes its moisture back.

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

What's Under the Finish

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 the best refinishing candidates live: solid wood over a crawlspace, often with decades of wear and plenty of thickness left. It is also where cupping comes from. Sanding a cupped floor flat before the crawlspace moisture is fixed produces a floor that goes concave the other way once it dries — so the moisture reading comes first and the sanding comes second.

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 where refinishing pays off most: homes of that period often have original wood under carpet, and when the wear layer is intact, refinishing keeps a floor that cannot be bought new. We check thickness at a vent or a doorway before recommending it.