When It Stops Being a DIY Job
Most houses on this side of Lakeville went up between 1955 and 2004, with the median build year sitting at 1984, and a lot of that 1980s-90s stock still has its original bottom seal track or a first-generation replacement. A worn vinyl strip you can peel back by hand, or a gap you can see daylight through along the bottom edge, is a DIY fix - cut a new astragal to width, feed it into the track, done. Where it stops being DIY is when the draught is coming from the side seals or the header, not the bottom. If cold air is pushing in along the vertical jamb seals, that usually means the door itself has racked slightly in the frame, or the track has pulled away from the wall studs. That's a structural check, not a strip-and-replace job, and pushing a new seal into a door that isn't square just wastes the material. If you've replaced the bottom seal twice in two years and still get a draught line across the floor, the door's out of plumb and needs a hands-on look, not another trip to the hardware aisle.
What to Check
Start at the bottom seal - pull on it. If it's stiff, cracked, or doesn't spring back, it's past its life regardless of how new it looks. Original seals on houses built close to that 1984 median are likely on their second or third replacement cycle by now, since vinyl in this climate band typically hardens and splits well before it looks obviously bad. Next, run a hand along the side jambs where the door meets the frame on a cold morning - cold moderate winters here mean any gap wider than a sheet of paper is enough to let in a steady draught, not just a draft you notice once. Check the header seal too, the strip across the top; it's the one people forget because it's out of sight. Last, look at the corners of the panels themselves if your door predates the 1990s - older panel doors in this area sometimes have foam insulation that's settled or separated from the steel skin, which reads as a draught but is actually an insulation gap, not a seal problem at all.
The Situation
If your house is part of that 1955-2004 build wave and you haven't touched the seals since move-in, that's the first thing to address before winter, not after you've already noticed the draught. We don't recommend replacing seals on a door that's visibly out of square - that's a wasted part and a service call waiting to happen anyway. One honest limitation: we can't diagnose a side-jamb draught over the phone with any confidence, because the cause could be the seal, the track, or the frame, and guessing wrong means a second trip. If the bottom seal test and the side-jamb hand check both come back clean and you're still getting cold air at floor level, that's worth a look in person rather than another seal swap.
