I live on the third floor of a prewar walk-up in Astoria, facing a side street that gets every Q69 downshift and a fair amount of box trucks. The two wood double-hung windows in the living room have original sashes, and the top sash rattles against the parting bead whenever a bus idles at the corner. I’m not trying to replace the windows; I rent. I’ve already done the basic stuff: re-puttied one loose pane, tightened the sash lock screws, and added adhesive foam strips along the bottom meeting rail. It helped with the low thrum from the street, but the thin metallic rattle is still there when the glass is closed and locked.

What I’m wondering is what actually works on the vertical channels of an old double-hung without making the window unusable until April. I’ve seen people use rope caulk, spring bronze, v-seal, wax in the tracks, and little rubber wedges. Some of those seem like they’ll fix the rattle but then you’ll rip the paint off when you open the window in spring. I’d rather not lose the ability to get air on a warm winter day.

If you’ve done this in a rental, what held up? Specifically: did you put anything on the top sash, or did you just leave it closed and treat the bottom sash? And did it stop the thin metallic rattle, or just the air leak?

Wait, I have the same thing! I just moved to Dyker in October and my bedroom window is original old wood. I shoved cardboard between the frame and the lower sash because the noise was driving me crazy at night. It helps, but it looks terrible and I can’t open the window. Is rope caulk the tan clay-like stuff? Do I need to remove it before opening, or will it just peel off? Also does it leave a film on paint? I asked my super and he just said “put a towel.”

Yes!! This is the correct answer for old double-hung windows: spring bronze weatherstripping. You don’t need the kerf stuff—that’s for newer windows with pre-cut grooves. On an old wood sash you nail the thin V-shaped bronze strips into the side jamb channels, and the sash rides against them. It stops both the rattle and most of the air. The key is to clean the channel first and run a block of wood gently along the strip so it compresses evenly, otherwise you’ll make the sash too tight at one end.

Have you looked at the sash cords and pulleys too? If the pulley is loose in the pocket, the sash can bang when a bus passes. Also, Lexel on the glass/wood joint works way better than old glazing putty if the pane itself is tapping. That stuff stays flexible. Don’t use silicone glazing in a rental—the landlord will hate it.

Cardboard and a towel is the tenant special, but the towel holds moisture and then you get that musty smell. I’d skip actual spring bronze if you’re renting unless you have a patient super—it’s not hard, but it’s permanent enough that you’ll need to paint over nail heads when you move.

For a quick fix I’ve used those little clear rubber U-shaped bumpers made for cabinet doors, pressed into the meeting rail and along the top sash. They don’t leave a mess and you can still yank the window open. Not as good as greenpoint_guy’s bronze job, but it kills the metal buzz.

Good points all around. DykerNewbie, rope caulk is the tan clay-like cord, and it usually peels off, but on old shellac or flat paint it can leave a slightly oily line; test a spot behind the curtain first. You don’t need to fully remove it to open the window—it compresses—but if you’ve got it packed in a heavy bead, it can make the sash stick.

Gowanus_G, the cabinet bumper trick is one I haven’t tried, and it sounds like the right amount of reversible. To greenpoint_guy’s point, I did check the pulley: the lower-left pulley on the top sash is loose enough to tap. I hadn’t thought about that being separate from the sash rattle. I’m going to snug the pulley screws and then do the spring bronze on the bottom sash channel only, leaving the top sash shut until I see how the paint holds up.

The one thing that surprised me is that the metallic rattle is less about the meeting rail and more about the side channel, so the foam strips on the bottom didn’t do much for it.

Okay, so I bought rope caulk last night. I pressed a thin rope along the top of the lower sash and the side channels. The rattle is maybe 70% better! But now my window is way harder to close. Did I use too much? I also didn’t realize I had to clean the sash channel first. Is it okay to leave the rest of the rope in the box? Does it dry out? Thanks for the tip about the oily line—I put a bit behind the curtain so we’ll see.

Too much rope caulk definitely makes it stiff. Roll a thinner bead, maybe half the diameter, and run a plastic putty knife along it so it’s flat. For the leftover, wrap it in plastic wrap and keep it in a drawer. But honestly, after the first real heat wave you’ll probably forget and crack the window anyway. Keep a putty knife nearby for when the sash sticks.

If you go the permanent route later, don’t sleep on new sash locks—old brass one on mine was worn so the sashes weren’t even meeting tight. That was half the rattle.