Reglazing and beading on Georgian sash windows

[Pabs63]

I have recently bought a Georgian house. Most of the windows are original and the house and in particular the windows are well known in the district which is also a conservation area. The glass has warped and there are leaks plus the windows are draughty. We like the original shutters that still work and so secondary glazing doesnt appear to be an option. The beading is not in a great condition in some windows and some will need replacing. I have a table router etc so that is not a problem other than the profile is not one i have seen before - see pic of the profile comb. The average window pane is 510mm x 190mm and throughout there are 150 panes. I am considering replacing the panes with single glazing hopefully with better thermal and acoustic properties. Does anyone know where I could get a custom-made router bit and any recommendations on the reglazing?

 

[fernicarry]

Looks like a similar profile as my windows. The profile is referred to as a feather astragal I believe (see this brochure).

I made mine using the same cutter as the stiles and rails by machining each side of the bead separately. I dropped the cutter down so that the stepped part was just below the table. The profiles on the two sides then meet at a point that you can sand to a curve if you wish.

Unusual arrangement of the panes, not seen that before. It'll be fun to paint! If the glass is the original cylinder glass (you can identify it by bubbles and general waviness) then you really should try to keep it as is.

You can get parting and staff beads (baton rods) that have integrated brush strips that will do a lot to reduce the drafts and you can machine a weather seal into the meeting rails.

 

[Pabs63]

Thanks very much Fernicarry. Yes they do look similar. I use Express Timber in Paisley for my sash window frame repairs. I did have a look at their feather astragal and thought it looked a bit dumpy. I'm over there shortly so will have a look. I will look into the brush strips. As for the glass, some of the glass panes have been scratched badly either when they were being cleaned or prepping the wood. I do like the aged glass and it would be preferably if i could polish out the scratches.

 

[fernicarry]

I did have a look at their feather astragal and thought it looked a bit dumpy

Modern mouldings seem to have a smaller radius on the ovolo so that could be why it looked dumpy. Last time I was in ETP they said they'd stopped stocking the feather astragal which is why I ended up having a go myself. A lot of my top sashes are original and have quite a large radius on the curved section similar in proportion to yours. The older replacements have a somewhat smaller radius and some replacements that I had made recently have a positively tiny radius. Maybe its because its faster to machine as less material is removed or maybe its to allow a deeper glazing rebate for DG. Whatever the reason its a bit annoying when you see new ones alongside old ones. The cutters I used in the picture above are Trend C266/C273 and are a pretty good match to my original profile. I'll probably have some offcuts left over if you want a piece for comparison.

 

[Pabs63]

Thanks. I have taken some measurements of my astragals and looked at the Trend C266 and as you say the radius have got smaller. By the looks mine is a probably compound radius )I need to clear all the paint off and get some precise dimensions). I have made a sketch - the 'wood' is what I could achieve with the C266 and the black outline and measurements are what I am after.

 

[fernicarry]

I think the Trend cutter is longer than you've drawn. The Trend drawing shows 17mm total depth and say 3 or 4mm for the step at the top gets you almost exactly at the 14mm height you are looking for. And if you subtract the depth of the paint its closer still. I'll measure it when I get home.