Drafty Door

Drafts around a slider come from a predictable set of failures. Crushed or worn weatherstripping - the brush-pile fuzz along the panel edges - leads the list, since it flattens with every slide over the years. Dried, cracked rubber gaskets and sweeps around the frame are next, hardened and shrunk by UV. Third is a door out of alignment, sagged on worn rollers so the panels no longer close tight against each other or the jamb. And a worn interlock, where the two panels overlap down the middle, rounds it out by leaving a channel for air right through the center.

The fix scales to the cause. Worn weatherstripping and gaskets are replaceable wear parts - fresh brush pile and seals sized to your door close most leaks on their own. If the door has dropped, the rollers are renewed and the panel squared so it seats tight, closing the gap at its source. A failed interlock is replaced so the panels overlap snugly again. It is usually a modest repair, but sealing the door only lasts when alignment is corrected too, since new weatherstripping cannot bridge a door that no longer meets the frame.

In Tampa Bay a leaky slider is an air-conditioning and moisture problem, not a cold-draft one. Hot, humid Gulf air pushing in around a poor seal makes the room by the door feel warm and clammy and runs your AC longer through the long cooling season - and it lets damaging humidity into the house. The UV here is brutal, so rubber seals dry and crack faster than in milder climates, and salt near the coast degrades them further. The heavy lanai-door use common to Florida homes crushes the brush pile quickly, which is why even fairly new doors in Riverview or Land O' Lakes can start leaking within a few years.