How to seal and draft-proof a sash window?

[ElleWeb]

Hi wondering if anyone knows how to seal a sash window to stop drafts from coming through. We are renting an older place and it gets terribly cold in winter.

[MitchellMc]

Welcome to the Bunnings Workshop community @ElleWeb. It's amazing to have you join us, and many thanks for your question about sealing out drafts.

The first step is identifying the gaps where the draft is entering. On a breezy day, you can detect drafts by holding a piece of tissue paper against the internal frame. If the paper moves in the breeze, you should seal that area. Use a rubber seal to fill the gap, and a wide range of options are available. 

I'd hazard a guess that the area where the lock is could be the culprit. In all the other areas, the timber slides within a rebate and wind would have difficulty penetrating there. If this is a window you don't open, sealing this gap could be as easy as applying some duct tape across the joint.

If you do some exploratory work and discover where the draft is entering, our knowledgeable members could have some other solutions for you.

While looking for ways to improve your home's heat-retention, check out this helpful guide: How to Winter-proof your home.

Please let me know if you have questions.

Mitchell
 

[ElleWeb]

Thank you @MitchellMc for the advice & warm welcome. 

The tissue trick worked quite well... much better than the incense method i had read about. 

there are a couple of drafts along the side sill where the wood has rotted (and subsequently been painted over) and also along the area where the lock is as you mentioned.

You mentioned a rubber seal might be the way to go. There seems to be quite a variety to choose from... I guess the next question I have is how do I know which seal to go with??

Thanks

Elle 

[MitchellMc]

Do you often use this window @ElleWeb, or does it stay closed during Winter? It would be significantly easier to solve this issue if the window was not in use.

Sash windows need room to slide up and down freely. Even with this gap, they often bind and get stuck. If the breeze was coming through the bottom, then you could adhere a foam strip there, and the window will compress it when closed. The sides are a bit trickier as there is limited room, and the constant motion of the window opening and closing will try to dislodge the seal.

I recommend leaving the window closed during Winter and sealing it up. You can use Moroday 6mm gap filler rod, and with a flathead screwdriver, compress and push it into any gaps. Insert the filler rod around the sides and at the top. You can then come back and tape over this joint for a secondary measure.

It won't stop the cold air from getting in, but a set of heavy linen or woollen curtains will prevent you from feeling the draft. That's not ideal heat-wise, but it could stop chills.

Let me mention one of our knowledgeable members, @TedBear, to see if they have any thoughts.

Mitchell

[TedBear]

Thanks for the tag @MitchellMc and Hi to @ElleWeb .

The window photos looks exactly like my sash windows did, with the exact same leaky-air issues.

I eventually replaced mine with double glazed window units, which fixed the problem, but with being in a rental situation that option isn't available here.

Therefore I'd go 100% with MitchellMc's suggestions and seal the windows off for the winter, as long as that won't cause other issues - i.e. provided that you have other sources of air into the room.

Thanks for the tip about Moroday Gap filler rod MitchellMc, which I hadn't come across before.

(Although that link didn't take me to it...  I saw it at   https://www.bunnings.com.au/moroday-6mm-x-5m-white-gap-filler-rod_p4061882 )

[EricL]

Hello @ElleWeb 

It's great that you've received fantastic advice from @MitchellMc and @TedBear. Just to add to the suggestions made, I propose sealing the window with Bastion 1200 x 600 x 30mm XPS Multi-Use Insulation Foam Board. Simply cut it with a sharp craft knife or Stanley knife to the size of the outside perimeter of the window so that you can slot it into its frame. I suggest using a straight edge or a long ruler to guide the blade while cutting the insulation. Please make sure to provide a little extra so that it fits snugly into the frame of the window.

Simply push the insulation into the recessed frame of the window to seal the entire window to prevent cold air from getting in. You can remove the foam insulation with a popsicle stick or the back end of a spoon. I've placed a diagram below to give you an idea of how to install it. You can still keep your window open in the morning and close and seal it in the evening. 

If you have any other questions we can help with, please let us know.

Eric

[ElleWeb]

@MitchellMc @TedBear @EricL 

Thank you all for the tips and very helpful advice..

To answer your question @MitchellMc - the window is generally shut during winter, but I do open on occasion when it's not so cold to let some fresh air in...  the only other way to circulate air will be to use a fan or dehumidifier / air purifier, which needs to be run from time to time anyway because of a musty smell in the room (can't seem to win with these old houses!!). I will try the gap filler rod & see how that goes !! 

@EricL that is such a clever idea!!  

looks like I will be busy this weekend!! Thanks again for your help!