Re-glazing a vintage timber sliding sash

[Possom]

I have a number of timber sash window which have their original single-glazed glazing.

As a consequence, although some of the windows are close to the floor, none of them have safety glass. In order to retain these windows I would consider installing secondary glazing.

If I installed the secondary glazing, what are opinions on retaining or replacing the existing glass?

When the secondary glazing is opened, then the exposed primary glazing is exposed and therefore still potentially dangerous if someone fell into it.

If the primary glazing is changed to a single-glazed pane of toughened safety glass (not heavier laminate), would this imbalance the weights? I'm unsure as to whether modern safety glass is heavier than old single glazing, though I imagine it is.

 

[crank39]

Toughened glass is only float glass that been heat treated and will weigh the same

 

[Possom]

Toughened glass is only float glass that been heat treated and will weigh the same

Okay, thanks very much. I didn't know that.

 

[ronniecabers]

Really old sliding sash windows maybe 2mm or 3mm glass....

Another option would be to ' safety film ' the existing glass

 

[Possom]

Really old sliding sash windows maybe 2mm or 3mm glass....

It'd be early 1930s.

Another option would be to ' safety film ' the existing glass

I hadn't heard of that. Is that something which glaziers install, or is it more a DIY thing?

 

[Deleted member 174758]

Another option would be to ' safety film ' the existing glass

I hadn't heard of that. Is that something which glaziers install, or is it more a DIY thing?

There are still some traditional joiners & glaziers out there who understand how to do this. Why not ring round?

 

[Deleted member 174758]

...

 

[gregers]

easy job to do,you may be abe to buy it from a local glazier,normally its sticky 1 side and roughly cut it to size and using a wet cloth with some washing up liquid take the backing off and place it on the glass,use a filling knife to push it into the corners and with a knife cut off the excess,then gently run out the bubbles and leave to dry.

 

[ronniecabers]

As has been said ....relatively easy to do if you know how to do it properly BUT I would still let someone with experience do it, or you'll more than likely end up with grit under the film from where the window hasn't been cleaned properly and also bubbles with washing up liquid in....and both those will make it look terrible. Also one thing to bear in mind is the safety film is there to do a job so it is functionatity over aesthetics, as I can nigh on guarantee , on glass in situ, it is never going to look 100% perfect ( but should still work out cheaper and easy than replacing the glass)

 

[Possom]

I've noticed it's possible to purchase the safety film on eBay:

http://www.ebay.co.uk/sch/i.html?_o...ty+glass.TRS0&_nkw=film+safety+glass&_sacat=0

Alternatively if having the glass replaced with new single safety panes, I wonder if it would be a 6:4 laminate on the lower pane is what would be required? Or perhaps simply a single pane (not laminate) of toughened glass. I know I can't use Pilkington K glass as a single due to oxidisation.

I wonder if there's any advantage to additionally having a single-glazed safety laminate (or a toughened pane) on the top sash (which starts high up) which is a pane which is not designed to slide.

Since it does not slide, any additional weight from the laminate glass would, presumably, not effect the sash weights. Though would there be any particular advantage or disadvantage?

 

[ronniecabers]

You can yes that stuff from Ebay....still comes down to how good you want it to look....
As goes the panes of glass..4mm tough is fine for regs, the only advantage s you would have with laminate are a/marginal sound isolation improvement and b/ laminate when it cracks stays together, tough when in breaks , ends up in lots oflitle pieces!
As goes Pilkington K glass, you CAN use it single glazed, As Pilk K is a ' Hard Coat ' Low e glass. we left a piece outside for 6 months and it had no adverse effects visible...however , if you scratch it, then it will leave a very very distinct mark on it ( so cleaning it can be an issue! ) The glass which reacts with the atmospheric conditions is ' soft coat ' low e , such as Planitherm, these I would not advise to use in a single glazed format of any form.

You would have a security/safety advantage of using Laminate/Tough Glass in the top panes , but provided they are above 800mm from the finished floor ( inc carpets ) inside AND outside then you have no building reg/legal requirement to have them Toughened/Laminated.

 

[Possom]

As goes the panes of glass..4mm tough is fine for regs, the only advantage s you would have with laminate are a/marginal sound isolation improvement and b/ laminate when it cracks stays together, tough when in breaks , ends up in lots oflitle pieces!

Would it be possible to have a laminate of 6:4 with one (or both?) panes Pilkington K? It the coated side(s) are placed directly against the other pane this would eliminate the issue of scratching it when cleaning. I assume only one side of each sheet is coated.

As goes Pilkington K glass, you CAN use it single glazed, As Pilk K is a ' Hard Coat ' Low e glass. we left a piece outside for 6 months and it had no adverse effects visible...

Oh, that's interesting. The reason I had mentioned oxidisation in my previous post is because a glazier I was speaking with informed me with respect to Pilkington K (not KS), "coating on the glass is made from metal and therefore oxidises and becomes cloudy when exposed to the air."

You would have a security/safety advantage of using Laminate/Tough Glass in the top panes , but provided they are above 800mm from the finished floor ( inc carpets ) inside AND outside then you have no building reg/legal requirement to have them Toughened/Laminated.

Also, with respect to laminate, I have heard that if a linseed oil putty is used then this can leach in between the panes over time and create a milky colour around the edges. I don't know if glaziers now would usually use glass tape nowadays instead of the putty, or if there's a putty which doesn't leach between laminate...?

 

[ronniecabers]

Would it be possible to have a laminate of 6:4 with one (or both?) panes Pilkington K? It the coated side(s) are placed directly against the other pane this would eliminate the issue of scratching it when cleaning. I assume only one side of each sheet is coated.

Anythings possible for a price... put bear in mind 6.4 laminate is two pieces of 3mm glass with a 0.4mm saftey interlayer. You can get 6.4 laminate ' K' . but the 'k' surface is exposed as per normal 'k' glass

Oh, that's interesting. The reason I had mentioned oxidisation in my previous post is because a glazier I was speaking with informed me with respect to Pilkington K (not KS), "coating on the glass is made from metal and therefore oxidises and becomes cloudy when exposed to the air."

When it first came out that is what we were told....but having tried it it myself ( and being skeptical ) , there were no adverse effects visible. As I said the ' softcoat ' version is much were suspetical to damage through being single glazed ( even touching the coating, four hours later a finger print would appear ) . The glazier you spoke to is correct about the type of coating used , but it is just much more durable then many believe, even our secondary Glazing Supplier use Pilkington K in a single glazed form.....

Also, with respect to laminate, I have heard that if a linseed oil putty is used then this can leach in between the panes over time and create a milky colour around the edges. I don't know if glaziers now would usually use glass tape nowadays instead of the putty, or if there's a putty which doesn't leach between laminate...?

This is very true...Linseed Oil will , over time , leech in and discolour the interlayer. When we glaze laminate we seal the edges with a foil tape to try and elimanate this. The other option is use a small wooden bead and then using glazing tape, but all this will increase the weight on your sash cords and unless the weights are altered you will potentially have problems

 

[Possom]

Anythings possible for a price... put bear in mind 6.4 laminate is two pieces of 3mm glass with a 0.4mm saftey interlayer. You can get 6.4 laminate ' K' . but the 'k' surface is exposed as per normal 'k' glass

Just to clarify this point.

Is the K surface applied to one side of the glass only?

If so, could you have the first 3mm K pane with the K side faced towards the 0.4mm interlayer, and the second 3mm pane with the K side faced in the other direction which would also be towards the 0.4mm interlayer? Therefore neither side of the window would have the K side exposed when cleaning.

 

[ronniecabers]

The coating is applied to one surface only..yes

I have only ever seen 6.4 laminate with the coating facing out but in theory
If you can find a laminate manufacturer who will put the two 'k ' surfaces facing then yes it is possible...BUT and this is a very big but , it will cost an absolute fortune , as it will become a specialised glass. You will never see you money back from it!