'double' glazing...

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tobble

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\'double\' glazing...

would appreciate the forum's opinion on the following idea;

Living aboard, I get significant problems with condensation. A dehumidifier mainly cures these, but I anticpate atime when I won't have access to mains.

I intend to improve the insulation (GRP hull) which should reduce the problem if not cure it, but have been wondering about windows - please save more general comments about the condensation issue for another post /forums/images/graemlins/smile.gif

One idea I had was to replace the windows, currently toughened glass in alu frames, with acrylic or similar, but instead of just one sheet bolted to the outside, also have a second bolted to the inside, so the coach roof side is 'sandwiched' between two layers of acrylic, and the grp forms a gap, to give double glazing...

problems with this might be condensation between the panes, minimised by a) sealing it on a day with low RH, and b) including some silica gel like wot comes with your new shoes.

another issue would be mosture ingress into the edge of the grp but that's easily sealed with epoxy and/or paint...

Am thinking about trialling the idea on my forepeak hatch, which is grp.

any opinions?
 
Re: \'double\' glazing...

Condensation will occur where it is warmer one side of a surface than the other. I would have thought that just DG the windows would have been a total cure. The most effective remedy for condensation is ventilation. I have bought a solar fan that fits in the ECS ventilite. That draws air through the washboard vents and kept the boat damp free all winter. It is almost noiseless. It was £60 though. Good price here
 
Re: \'double\' glazing...

Not convinced ventilation is the way to go for a liveaboard (different story for you 'weekenders' /forums/images/graemlins/wink.gif

trouble is you end up throwing away vast quantities of heat. of course this trick can work well in particular circumstances, i.e. while cooking.

have toyed with the idea of a heat-recovery ventilation system, but vilates the KISS principle somewhat! would beinteresting to experiment with though...
 
Re: \'double\' glazing...

A few winters ago we had lots of condensation in the cabin we slept in, so pulled the headlining off the hull sides and lined with 10mm polystyrene and refitted the lining, and the windows that are aluminum framed with toughened glass, we stuck clear 5mm perspex to the inside of the frame with double sided tape just for the coldest months. That made a vast improvement for us and if you have problems with the hatch, then make an insulated cover for it. Good luck.
 
Re: \'double\' glazing...

With my previous boat, in the winter, I fitted "cheap and cheerful" polythene sheeting, which was sold for the purpose. It is fitted on the inside, onto double-sided sticky tape, and when heated with a hairdryer it shrinks, and tightens up. It worked very well, and in the Spring, I just stripped it off again.
I wouldn't bolt on an internal sheet of acrylic. you are certain to get condensation between the panes.
 
Re: \'double\' glazing...

This winter, along with the de-humidifier, we used the household temporary double-glazing film with double-sided tape for our boat to reduce condensation. Cheap to buy and it helps reduce heat-loss too. Admitedly we still get some condensation on the inside of the alu window frames when the RH is high but not on the panes.

We had thought of using rigid polycarbonate sheeting but the cutting was the problem for us. We have 17 windows to do. How did you cut it, Happydaze?
 
Re: \'double\' glazing...

Condensation is caused when humid air comes in contact with a surface where the temp. is below the dew point for the air water mixture. It can be avoided in several ways, first by reducing the addition of water in the internal environment, this can be in the external air already or can be added substantially by burning fuel, particularly gas, if the air can be kept warm enough the water stays in suspension like a solution,but electric heating can result in discomfort from humidity that is to low. Ventilation will remove or reduce the damp air before it condenses. You have to be wary that in a boat if condensation does not occur on the windows it is likely to occur somewhere else, possibly causing more damage. While damp windows are an annoyance they may be preferable to condensation behind linings. Insulation will only prevent this if the vapour can not pass it to reach a cool surface, this is why in lightweight building construction a complete vapour barrier should be placed inside the insulation with only breathable membranes outside it.
 
Re: \'double\' glazing...

for the record :- real double glazed glass units are sealed units with a spacer bar sealed edges with a hot melt, the spacer bar is filled with silica desicant forming a hermetical seal, the air inside dries thanks to to the silica

then you go to Low E glass - then low E argon fill - then !!!!!!!!
 
Re: \'double\' glazing...

Thanks for all the responses guys. Think I'll try the idea on the hatch - if it gets too much condensation I can just remove the inner pane!

Had seen the film stuff before, heard elsewhere clingfilm will do. maybe a good temporary fix but I was thinking of somehting a bit more robust.

When I get round to it I'll report back...
 
Re: \'double\' glazing...

yep thats --- active ---- solar ----£££££££££££££££££££
 
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