Horizontal sliding window air gap?

I just purchased a late 70’s split level with fairly nice wooden horizontal sliding windows. In preparation for winter I’m trying to close up any gaps in the windows and doors to make the house a little more efficient. I’ve discovered that at the base of the window where the two panes meet there are large gaps (½” x 1”). It seems that when the windows were originally installed there was some sort of plug that filled this gap that is now disintegrated or gone. Anybody know what those plugs are called? If you can buy replacements, or do I just need to make something out of wood and felt?
The people at the hardware stores are no help the gaps are way too big for just some weather stripping.

OK, I waited for someone more knowledgeable to answer this.

I do not understand what you mean by “the base of the window where the two panes meet”. Do you have pictures? Those would help me, (and probably others), help you.

It sounds like these are double hung windows and this is where the upper sash and lower sash meet…right?

So, in this picture, the gap is where it says ‘upper meeting rail’?

A gap that big isn’t right, it sounds like the window is damaged. Do either of the windows, upper or lower, move back and forth? That is, can you push them together to close the gap? I’m thinking either the rail/guide is broken or the window (the sash) is deteriorated enough that there’s just that much play.

I’m going to start with this question before I offer up some thoughts.

Isn’t a “horizontal sliding” window a casement window? In other words it slides right and left as opposed to up and down.

horizontal windows i’ve seen move away from each other to allow free and easy sliding. when it is at the closed position then the panes move together to seal. so the tracks aren’t straight but take a jog at the closed sealing position.

so a gap you see when the window is half open is real wide. the gap in the closed position is small and filled by ordinary window weather stripping.

are the windows traveling the full distance? can you lock the window when closed?

:smack: I don’t know why I missed that. A casement window cranks outwards. Well, it doesn’t have to crank, but it is on hinges of one kind or another and swings out, but you’re right, this probably slides from side to side.

So, I guess the OP has a window like this and is looking for the seal that goes in the center.

Is there a manufacturer name and model number on it somewhere? If there is you can probably find a local dealer to get the part if they still make it.

But what I was saying earlier we still need to figure out if you’re missing a seal or something is broken. Replacing a seal (or replacing it with something from Home Depot) is one thing, but if the parts aren’t coming together because of a different issue, that’s something else altogether. An inch is a huge space so I’d really like to know if there’s any play in the window when it’s closed. Can you push it together easily. Does it rattle around a lot in the wind?

BTW, this is something you have to deal with, not just for the cold, but snow and rain are going to come right in and do a good bit of damage.

Install this. Its the most efficient way to fully insulate any window.

That helps for windows that have a draft, but if you have a one inch gap. That needs to be dealt with first. As I said earlier, the OP is going to have snow and rain coming right in. Even just putting a small piece of plywood over the gap with some finishing nails will keep the elements out. He can put the shrink wrap on afterwards, but the giant hole needs to be closed up first.

Sliders are notorious for leaking air. Keeping them locked helps snug them up tighter, but they still are drafty. My 1950’s ranch had thestandard aluminum type. I had them replaced a few years ago.

I’m not sure what gap the OP is seeing. My sliders had maybe a 1/8" gap at most. Just enough so the slider didn’t hit the fixed panel when it was opened. The track on mine was worn and that kept it from sealing tight.

I think the 1970’s sliders were different.

A sliding window frame should be 4 sides with wheels at the bottom.

Maybe the slot is for a wheel to go in.

Maybe the slot is for a rubber stopper, or maybe it was for some sort of lock or anti-rattle mechanism.

The only fix the OP wants is to seal gap, and OP doesn’t mention the need for security or making the window slide better, or to stop it rattling in the wind or any other need… so he can just fill it.

I didn’t know they had wheels on the bottom. I can imagine a situation where one set of wheels has broken, either the wheel has physically broken or the axle broke and the wheel is pushed up inside, or the entire mechanism is missing for that matter. Either way, if one wheel isn’t there, that side would be lower than the other. If the window isn’t square in the casing, the mating point may not seal correctly depending on how much overlap there is when it’s closed. It’s a long shot since I’d guess the OP would have mentioned the window being somewhat crooked, but as long as we’re all just taking a bunch of guesses I figured I’d toss this one out too.

Yeah, the original mid-60s sliders for this place were like that.

Back when I was renting an apartment, I bought a new AC unit for the bedroom window. This thing came with some 1" × 1" × 48" black foam which could be trimmed to fill the gap in the open window. Perhaps something like that would work?

Single glass windows really aren’t worth repairing. Even covered in the shrink film I linked earlier. Getting my house’s windows replaced with double pane glass was the 2nd best investment I ever made.

Best investment was getting vinyl siding. They installed a foam insulation board under it. My 1950’s ranch has no insulation inside the walls. (I got blown insulation in the attic when I bought the house). That foam board insulation on the walls made a noticeable difference in my natural gas bill.

I just want to say thank you to everyone who answered I try and watch my threads but figured this one was never to be seen again.

Yes, Joey P, that’s the type of window I have. The sliding portion of the window is on a track and is slightly smaller than the stationary portion. There is nothing broken with the window it’s more of a design issue. When the smaller sliding portion of the window is in the closed position there is a gap at the base of it between the track and the stationary window. From the evidence at the base of the window this gap was filled with a sponge like plug. I figured these plugs are a common maintenance item and could be found at the hardware store, but as of right now, no such luck.

Thanks again to everyone who chimed in.

You mean like that hole that we can see in that picture? I think that’s supposed to be there, it’s probably what allows you, on that type of window, to push it up and swing it over the track to remove it.

If you just need to get through the winter, you could jam some cotton or even an ear plug (if that’ll fill the opening) into the hole just to close it up. Then use shrinkwrap that Aceplace pointed out. You could also try Googling the model number to see if there’s a part missing, but I doubt it’s the case.

If this is a 70’s vintage window there is likely no parts still made for it. Window technology has changed a lot since then. There are however a lot of standard window parts and hardware that can be probably be adapted, but you are unlikely to find them at a Home Depot. Architectural hardware suppliers will have much of this stuff or you can try some online window hardware suppliers. Another option is to go to a building supplies recycler and see what they have.

All of the things above sound like more time than getting a piece of felt, cutting it to shape and mounting it with some form of plate or bracket.