Weather Seals and Draughts in Sunnyvale: What Your Garage Door Needs

Local detail

What the Weather Here Does to It

Sunnyvale sits in a mild temperate band, so you're not fighting freeze-thaw cycles that crack seals overnight the way colder towns do. What you're fighting instead is slow fatigue. Rubber and vinyl weatherstripping here breaks down from years of UV exposure, warm afternoon sun on a west-facing door, and the steady expansion and contraction that comes with daily temperature swings rather than hard freezes.

Most houses in this service area were built between 1947 and 1987, with the typical build year sitting around 1964. That means a lot of original door jambs and seal channels are now sixty years old, and even seals that were replaced once in that span are likely due again. The 1960s and 70s construction that makes up most of the stock here often used aluminum track frames paired with whatever rubber seal was standard at the time - material that was never meant to last six decades of Sunnyvale summers.

The honest limitation: a new seal won't fix a frame that's warped or a track that's pulled away from the wall. It only works if the opening itself is still square. If the gap is uneven top to bottom, that's a structural issue, not a weatherstripping one.

The area

When to Get Help

Call someone when the draught you feel isn't just along the bottom edge but along one whole side of the door, or when you can see daylight through a gap that wasn't there last year. A bottom seal that's flattened or cracked is a DIY swap in most cases. A side seal that's pulled loose from a bent track, or a door that doesn't sit flush in its frame anymore, is a different job entirely.

If you're hearing a scrape or grind when the door closes along with the draught, don't just reseal and move on - that's usually a roller or track problem wearing a path into the weatherstrip, and a new seal will fail again within a season.

Houses built in the 1960s and 70s wave that makes up most of this area sometimes have jambs that have shifted slightly over the decades. If a seal won't seat evenly no matter how you adjust it, that's worth a second look before you buy another one.

What we find

The Situation

Across the neighborhoods here - Old Mountain View, Cuesta Park, Heritage District, Sunnyvale West - the housing dates mostly to that same 1947-1987 stretch, median right around 1964. A lot of these doors still have whatever bottom astragal and side seal came with the original install, or a one-time replacement from years back that's now brittle and cracking at the folds.

Of the 110,090 owner-occupied houses across this service area, a good share were built before anyone was thinking about insulated garage doors or dual-durometer seals. The original rubber on a lot of these doors has gone stiff from decades of sun, and stiff rubber doesn't compress against the slab anymore - it just sits there, letting air and bugs through underneath.

This isn't a dramatic failure. It's slow. Most owners notice the draught around the time they notice the gas bill creeping or a line of dust along the bottom edge inside the garage. By then the seal has usually been failing for a year or two already.

How we work

What to Check

Start at the bottom. Press a hand along the full width of the closed door at floor level - if you feel air moving anywhere other than dead center, that section of the bottom seal is compressed, cracked, or sitting on a high spot in the slab. Next check the two vertical seals along the sides of the frame; on older Sunnyvale-area houses these are often the original strip, and they go brittle long before the bottom seal does because they take less foot traffic and get ignored.

Look at the top seal too, where the door meets the header - on 1960s and 70s builds this is sometimes missing entirely, since it wasn't standard on every door from that era.

If all three seals look intact but you still feel a draught, the problem is probably the door not sitting square in the opening rather than the weatherstripping itself. That's worth having someone look at in person before you spend money on seals that won't solve it.