Laminated glass in 100YO double hung windows

[stu71]

Hi Guys,

I am in the process of renovating a couple of 100 year old double hung windows - ie. out come the sashes, replace the glass (sash and sidelights), stripping all the paint off, new sash cords, re-painting and putting it all back together. Big job but hopefully will look stunning afterward - not to mention not needing the full treatment for another 100 years.....

One upgrade that I am planning is to replace the 3mm float glass with 6mm laminated for security and noise. This will probably also require replacing the counterweights as the sash will be almost double the weight. The other challenge is that I want to retain the period look by fitting the glass with putty, but Pilkington's website advises that linseed oil putty "should never be used with laminated glass". I'm guessing that this leaves me with two options; silicone and timber bead or silicone bed and putty to finish.

Any advice?

Stu

[BrissyBrew]

I want to replace the galss in some old windows in my Queensland with Laminated glass so I am interested in the outcome on this one. I note that mine are nowhere near as fancy as double hang sashs, they look like a sash however it is just timber sliding in a timber frame, no weight, just a little metal prop to keep the window up.

[colinC]

Howdy Stu

Don't know if this helps but you can bring the glass up to AS1288 safety standard by simply applying a clear 100 micron safety film to the inside surface. This is quite easily done and much cheaper than reglazing. Of course this would not improve noise reduction. Realistically though there is very little difference between noise levels transmitted through 3mm and 6.38 lam glass anyway. You really need 10.38+ glass or, better still, an air gap as in double glazing to get any effective decrease in noise levels.

Cheers
Col

[rhancock]

I'd go with the timber bead - lots of houses here have timber beads on both sides - often with nothing to seal the gaps - but then most windows here have hoods, so don't get much rain on them.

Brissybrew, your windows are very common. Fully hung sash windows are a fairly specialised piece of work, so lots of houses just have a timber bead and a catch - great when they land on your fingers - or your head! There's not really any way of installing the sash weights etc without starting over. There is a new version which uses a plastic track to hold the window in place, but again you'd have to start from scratch. You won't have to do any near as much work as Stu, as the extra weight isn't going to change the way the window works, but you will have twice as much weight to lift every time you open the window.

[baboon]

if you want to use putty, but recommended not. my best advice is go for a timber look a like

get a beading which has the same angle to it and place it in and bead it off, it will have the same look as a good putty job.

to make sure it looks right place it in and make sure it is proud out of the window rebate by 1 mm ( this is with the glass in) and once beaded off , just sand back the proud and it would look a like.

another option is use a small 5x5 bead to do the glass in and putty over top, the idea is to not let the oil come in contact with the film in between the glass as it will eat away.

or the plastic coated beads.

there are a few options, let me know how you go and which one you take.

NAthan

[dirtydeeds]

i repair and refurbish box sash windows for a living, hope im not teaching ducks to quack

you will need to make the glazing rebate deeper, reducing the internal ogee / lambs tongue / other moulding

this increase in weight usually requires lead weights to be installed rather than cast iron (double the weight in the same size box)

if your building regs require beading even on small panes of laminated glass do it

its childsplay, bench saw and block plane





if you are doing this much work install new sash pulleys, mighton here sell them with roller bearings

if the local timber merchant doesnt stock the parting bead and staff bead they are easily made using a block plane and bench saw

[dirtydeeds]

somebody said you will need twice the effort to move the sashes

im going to tell it as it is, hes talking bollocks

if you need more than 2 lbs of effort to move a sash (of any weight) you havent done the job right

[rhancock]

You're right, a properly installed sash can be opened with one finger by an 80 year old. Unfortunately over here, a lot of sashes were installed on the cheap, without the sashes! In effect they're just a window which slides up and down in the window frame. To keep them open, you just use a catch. So, you have to lift the entire weight of the window - no sash rope, no pulley, no weights - terrible design, well known for bashing your fingers and your noggin if you're not careful.

So, I'm happy to admit talking a lot of bollocks at certain times, but this isn't one of them. If I can find some pictures, I"ll post them.

[dirtydeeds]

rhancock id like to see the photos, can you get some detailed shots

reason being is that the windows you describe sound simlar to the very earliest versions of box sash windows (1500s or so)

they had no weights and were held open by wooden pegs and ive never seen one although the basic principals are no different to a "modern" box sash window

the earliest box sash window ive worked on was a mere 250 years old, better still it was a real unusal one. a bayed venetian with the bays being single side hung. yes yes i know the sides of a venetian dont move. these did

and even though they were single side hung they moved without racking in the boxes

[rhancock]

I googled it last night, but couldn't find any pictures. They're basically a cheap way of doing a sash window, rather than an old one, although I suspect they date from Australia's early history when there was a need to build lots of houses quickly and cheaply.

Maybe someone on the forum has sash windows without weights which they can photograph? Short of going around to houses I used to live in and taking photos, I can't think what else to do!

[pawnhead]

An unusual, and cheap method was used in my 50 year old pre-fab house. The double hung, spring loaded sashes were hung directly off the framework.
No separate window frame at all:

http://i7.photobucket.com/albums/y266/holgerdanske/th_P7010034.jpg (http://i7.photobucket.com/albums/y266/holgerdanske/P7010034.jpg)

[stu71]

Thanks for your help guys, I ended up getting Hakea at Tullamarine to do the install for me after I had prepared the frame. They prefer to finish with putty on all their work, and for my job bedded the glass in silicone then finished with putty. Looks great!

I knew that I would need to beef up the counterweights, now I just need to find a source of lead counterweights! The sash now weighs in at 16.5kg! I'm going to try A&R secondhand dealers at Campbellfield as they advertise counterweights, but I'm not too confident that they will have lead ones so I might need to do some searching.

Any suggestions welcome.

[rhancock]

Back in the day my dad used to cast his own, and then you'd shave them down so they were spot on! No idea how he did it though....

[dirtydeeds]

the way i cut down lead weights

get your drop saw (hopefully lots of TCT teeth), spin it up, spray both sides of the blade with plenty of PTFE spay

load the weight into the saw, spin to full revs THEN lower it into the lead

DONT drop the blade in IT WILL SNATCH and stop sudenly
DONT push the blade down IT WILL SNATCH and stop suddenly

use more PTFE spray for each and every cut

with this method even my "toy" 24volt bosch is more than capable of cutting a 50x50 lead weight




as for reducing a lead weight "to weight" use a bastard file, its a very old and very effective method