Insulation Removal in Burlingame, CA

Local Context

Sixty Years of Blown-In Fill Above a Ray Park Ceiling, and What Moved Into It

Rodent contamination is not localized, which is the part owners find hardest to accept. Roof rats (Rattus rattus) reach Burlingame attics through the mature street canopy, from the eucalyptus rows along El Camino Real to the big trees over Burlingame Park and Ray Park, and once inside they run the same routes through blown-in fill night after night, urinating along every one. Urine wicks through loose material and does not stay where the droppings sit. What looks like one nest in a corner is usually a network of compressed runways crossing the whole attic.

The material itself is often finished anyway. With a median build year of 1957, plenty of Burlingame attics still hold original low-density fill or thin batts, flattened by decades and doing very little for the house. In the pre-1940 Easton Addition and Burlingame Terrace houses we regularly find several layers added over the years, with the oldest at the bottom still holding whatever the roof leaked in 1970. Wet cellulose stays wet through a Burlingame winter and turns into a fungal substrate directly above the ceiling.

Handling matters because dust is the exposure route. Dried rodent urine and droppings go airborne when disturbed, which is why this is a HEPA-vacuum and protective-equipment job rather than a shop vac and a paper mask. Insulation in a house built before the late 1970s also has to be evaluated for asbestos-containing material before anyone disturbs it. And sequence is not optional: exclusion comes first, because new insulation blown into an attic with an open rafter-tail gap is simply new nesting material.