Fumigation in South San Francisco, CA

Local Context

When Three Findings in a Westborough Split-Level Are Not Three Colonies

Fumigation is a scope decision, not a severity one. Drywood termites (Incisitermes minor) live entirely inside wood, and one house can hold several unconnected colonies at once. Drill-and-inject works well where we can find and reach a gallery. It does nothing for the one two bays over, behind stucco, inside a closed roof assembly, or above a plaster ceiling in a pre-1940 bungalow near Grand Avenue.

The mid-century stock hides wood its own way. Split-levels and ranch houses across Westborough and Buri Buri run beams and top plates continuously from the eave through to the interior, with low-slope roof sections and wide overhangs where drywood termites get in above the ceiling plane. Once galleries run the length of a member like that, most of it has no accessible face. Gas reaches all of it because it travels as a gas — into joints, checks in the wood, and voids nobody can open without demolition.

This city also puts real limits on tenting. A tarp has to seal to the ground around a complete structure, which rules out attached townhomes and the podium apartment buildings along the transit corridors unless the whole building goes at once. Wind is the other factor: the marine air that funnels through the San Bruno Gap crosses the exposed hillside lots at Paradise Valley and Terrabay, and tarp crews plan around it.