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Re: D.I.Y. Double glazing.

PostPosted: Thu Apr 28, 2011 11:06 am
by munrre
Lucky chooks, straw bale and double glazing!

I had some success with Clear Comfort.
Thin plastic stretched over the frame and tensioned using a hair dryer.
About $200 would be enough to do a whole house.
Your size of window may cause issues though. It could also be used on prefabricated frames.

Also, don't underestimate the efficiency of floor to ceiling curtains.

Re: D.I.Y. Double glazing.

PostPosted: Thu Apr 28, 2011 11:57 am
by Co2
Hi Nige & People,

I used to work in the double glazing industry in the UK, over 20 years ago.

Gaps are good.
As I live in a cold house as well, I put some 3 mm thick polycarb sheeting, over the outside of my sash windows. There is a 2.5 cm gap on the top sashes and 6 cm on the bottom one. It has eliminated condensation on the inside, and the glass remained warm, but most importantly no more draughts! I made it so you can remove the bottom piece in summer. As it is south facing there is no problem with sun on these windows.

I do not think that you will be able to salvage glass, as it hardens as it ages, and cutting it will probably be impossible? Glass coating work, but only in cretin circumstances, and is not in my opinion, worth the $!

There are some companies that do double glazing using plastic, but again very expensive, around $300.00 + per Sq meter!

Some Uk companies supply double glazed units to Australia. I have not researched it, but I have heard that it is cheaper to import the units than to buy local, I will look in to that one!!

If you post a picture, I might be able give you an insight how you achieve a solution.


Re: D.I.Y. Double glazing.

PostPosted: Thu Apr 28, 2011 1:48 pm
by Nige
Thank you all so much.

Having had a fresh look at the window frame the piece of glass will be 255cm x 165 cm in size.
I will probably mount the second piece of glass on the inside rather than out as originally was the plan due to the 7cm horizontal depth of wood where i can attach all beads, mount the glass etc.
Fortunately again due to the size and shape of the house it will be easy to manouver the glass in and out.

Now I just need to chat to some glazier mates to see how many cases of beer this will cost me in removal & transport of doner pieces of glass. ;-) Total cost including beer should be around $90-100

I need to dive out but will have a go at attaching some photos when I return. Thanks again for all input so far.

The money saved will go on a few water tanks.



Re: D.I.Y. Double glazing.

PostPosted: Thu Apr 28, 2011 7:05 pm
by emmsav
Hi Nige,
You might find it useful to check out the Alternative Technology Association website

They produce the Renew magazine in which I seem to recall seeing at least one article on double glazing, including DIY projects. I think you can order back issues/download past articles through the website.

Good luck!

Re: D.I.Y. Double glazing.

PostPosted: Thu Apr 28, 2011 9:18 pm
by feral errol
I had a north facing 180 x 210cm set of 4 windows done with secondary glazing a few months ago.

The spacers are siliconed in place around the window periphery. They are made from 10mm thickness expanded foam pvc sheets. The strips can be precut to size by major plastics suppliers. I used a foam pvc grade suited for outdoor foam signage, as it has high UV resistance and should not deteriorate easily.

To do the test area of 4 windows using secondary glazing it cost me -

$70 for foam strips and glazing silicone and
$280 for the glazier to measure cut and install the second panes for all 4 windows

The total cost was $350 for the 4 windows and about an hour of my time to clean the windows and place the strips. I cleaned the inside of the existing window thoroughly with methylated spirit and then siliconed on the pvc strips to the existing window glass borders. Make sure to seal the corners well with the glazing silicone to prevent moisture seepage.

I let the silicone cure for two days before having the second panes installed. Trim any excess silicone from the second panes mounting surface.

I am led to believe that the secondary glazing method (with a 10 - 16mm air gap) will provide approximately 80 - 85% of the thermal transfer resistance of conventional double glazing (when using 4mm float glass). For the windout window/s I have had to reduce the foam spacer thickness to 6mm due to space constraints. I realise this will reduce my thermal efficiency on this window, but it is better than no gap.

When using 5mm hardened glass for the lower window sections (as per Victorian building regulations) the extra glass thickness should slightly improve on the thermal transfer rating.

For anyone contemplating doing secondary glazing, I would recommend using a qualified glazier. For those who must do it themselves; check the relevant state building code to ensure that the correct grades of glass are used for the application. For example, in Victoria you must use 5mm thickeness hardened glass for lower windows.

I live approx 80 km east of Melbourne and we have already been down to 2degrees C overnight, without any condensation between the test panes in the morning. I thought about the silicagel sprinkle in the base of the window (on the foam) but did not do it on this trial set of windows. These windows are the ones that always have condensation issues in winter if any. All appears well so far :D

I think I can notice the difference in room temperature and there is nothing visually different apart from the PVC foam border around the window. Black foam is the best visually although white looks good also.

And all this fun for 10% of the cost of conventional double glazing 8-) .

Re: D.I.Y. Double glazing.

PostPosted: Sun May 22, 2011 4:38 pm
by Nige
This is in part a test post to see if I can upload house photo with windows to be glazed...

The main piece of glass is 1.65 x 2.55 meters the three at the end are 150 x 300 (the smallest ones)
It makes for a great window during the summer but a huge heat loss during winter. ;-)
Windows glaze.jpg
Window 1.65m x 2.55mtr

Re: D.I.Y. Double glazing.

PostPosted: Sun May 22, 2011 10:44 pm
by feral errol

That set of windows look like they are made for secondary glazing I think.

In the rooms I have done, I notice a difference in the heater settings required to maintain a comfortable temperature in the room. The room also has less outside noise than before.


Re: D.I.Y. Double glazing.

PostPosted: Tue May 24, 2011 8:56 pm
by Nifty
A bit off topic, but maybe relevant anyway. We have a place built about 6 years ago which features "Comfort Glass" on the north wall - floor to ceilng glass doors. It's supposed to reduce glare and minimise heat transfer, and it does that very well. However, I would much rather allow the heat from the winter sun to come in - the difference in warmth between standing inside the doorway between open and closed is astounding! If I was going to live there permanently I would swap the fancy glass out for something more basic, and some better curtains. We are located a few hundred kilometres south of your place.

Re: D.I.Y. Double glazing.

PostPosted: Thu Sep 01, 2011 6:52 pm
by Nige
Brainwave alert!

I just found on the ATA forum a link for an american company that supplies not only double glazing but even quad! oh happy days.
But more importantly rather than buying from the UK I may just purchase all windos for replacement from the US as due to the FTA the howard govt signed with the US anything of US origin is duty free. ;-)
So only GST, CIF, Shipping, I can do my own customs clearence oh and should avoid dock charges if I get the windows imported as part of a consol / lsl

Cost wise... still over 50% ahead of local wankers trying to tell me e-glass is worth so much extra coin.
I'm sorry but they can go masturbate over some other poor suckers face.

Re: D.I.Y. Double glazing.

PostPosted: Thu Sep 01, 2011 7:33 pm
by Tracker
pboyle wrote:An option is to use a plastic spacer between the windows (12mm) that you could get from a glazier.

You just stole my thunder..
I was going to suggest two methods.

One - to use a router to create a recess in the inner timber face (Real easy as you just follow the existing beading), and then drop a sheet into it and a simple beading over the top.
Then - the use of a drop in extrusion to provide a support, and then beading to hold it in place.

I would question the need for any sealing at all.. You only need to control convection leakage, surely..

Many DG's that I have seen, have actual holes at the bottom/inside

Still gona be expensive as you will need thin laminated glass (I understand)... :roll: