Draft Stripping a new Sash Window

[Roger H]

Hi all.

Some advice required. I got a couple of nearly finished dg timber sash windows off ebay. Unfortunately built without draft stripping so I plan to replace staff beads and parting beads with draft stripped versions.

Some questions:

There is no parting bead at the head of the window. Should I rout and insert draft strips into the top rail?

Should I rout and do the same to the bottom rail.

The meeting rails are fairly snug but should these be routed too?

My concern is that if I rout the top and bottom rails, the meeting rails are no longer going to sit flush so maybe relying on the brush strips in the staff beads is sufficient?

Thanks for any thoughts.

 

[plasticpigeon]

The staff/stop bead will seal the botton sash so you dont need a parting bead there. I think a parting bead on the bottom sill would be really bad as there would be a channel outside of the sash that the bead would sit in that could collect rainwater and rot the sill. You could rout the head for a parting bead, but the outer lining will seal the top sash to some degree. The leaks through the meeting rails and at the top of the sash will be less than through a trickle vent that seem to be on so many windows, and certainly less than big holes and air bricks bashed into walls in old houses that I see a lot. I would just put brush seals in the staff and parting beads and be done with it!

 

[Feltwell]

A slightly different view. I put parting beads in with brush seals top & bottom of the window, but with a joint midway so the brush seals are facing outside for the top and inside for the bottom window. I also put brush seal staff beads in, so yes that does mean the bottom sash has seals on both sides, but this has the advantage that the sash slides very smoothly - and the bottom sash tends to get used more than the top.

For the bottom of the bottom sash, and the top of the top sash, I route a very narrow groove in them and use a bubble seal similar to this - they compress down to virtually nothing.

https://www.reddiseals.com/product/timber-bubble-seals/

Not strictly needed for the bottom sash, as PP points out the staff bead does seal there, it's just easy to fit so I go for belt & braces! For the top sash this will be a lot easier than trying to cut a groove for a parting bead into the head of the box frame.

For the meeting rail I route a carrier and brush seal in to the outside of the bottom sash, so it's hidden from the inside even when the window's open. I tend to use self adhesive carriers but I also paint over them before the brush seal is put in and the sash fitted. The adhesive sticks well to the bottom of the freshly-routed groove but the paint seals it in for good, just in case the adhesive deteriorates with age.

https://www.reddiseals.com/product/flat-carrier/

Depending on how well your sashes fit the meeting rail may still be OK or you may need to plane a little off the bottom of the bottom sash and top of the top sash. I've always been renovating existing old windows so they tend to need adjusting anyway, sometimes having to plane some off to get a good smooth edge, glue a new strip of timber on and then plane back again to get the right fit!

There's other ways of draft proofing of course. I'd avoid plastic parting beads though, they don't look great. I put my staff beads in with brass screws now rather than nailing them in, just to make them easier to take off again in the future if need be. Parting beads should just be a friction fit, no need to nail them in, paint will mean they can't come out easily anyway. If the groove is knackered - some of the ones here were - you can get plastic u-shaped repair channel, which works well and is invisible once painted over.

The main draught I find after all this comes through the sash pulleys from the weight boxes. How it gets in there when I've sealed the box to the brickwork is a mystery I've yet to fathom! Lack of background ventilation isn't exactly a problem here......

 

[plasticpigeon]

After reading the original post again, and Feltwell's reply I realise I comlpetely misunderstood what was being suggested. The suggestion was routing top and bottom rail of the sash for draft proofing not routing head and sill for a parting bead!!! That sounds much more sensible to me, as does everything Feltwell has written!

 

[Roger H]

Thanks both - yes pp, I did not intend to fit a parting bead to the cill. I like the sound of the 'flat carrier' but will see if I can manage to rout out the head of the frame to take a parting bead as first choice. Many thanks.

 

[wobs]

Like most here, I use the timber beading with brush pile draught proofing. I notice that Reddiseal are now selling beading in Accoya, which I might consider for our parting beading.

As for the other edges:
I rout out the top of the top sash for the flat self adhesive carrier.

The meeting rail - I used to rout out one of the sashes for more brush pile, as the top sash, but the last window, I chickened out, as I couldn't get the router to safely run along the edge. I have broken a window in the past doing this, so I justified it as: a. The sash was slightly warped, so wouldn't have met perfectly anyway, and b. it provides ventilation*.

The bottom sash, I just use the staff bead with the brush pile. I don't rout it out, as it can get wet. I am in the process of replacing two bottom sashes, as the joint have gone on them.

In addition, colour choices are an interesting issue, as the lower inner runner should be the same as the outer runner colour.
http://www.periodproperty.co.uk/ppuk_discovering_article_041.shtml

I am due to do some sash windows this year, just as soon as I get the chance.