Polycarbonate 2nd glazing

[Matheous-2]

Anyone replaced (or secondary glazed) a double glazed glass conservatory roof with polycarbonate? What were the pitfalls-if any??

[AlBags]

1. Hazing or yellowing of material.
2. Light transmission reduction compared to glass.
3. Eventually, masses of thunderfiles will be inside the cavities (no matter how well sealed you think the cut ends are)
4. Very noisy in heavy rain.

Need any more?

[alavahalf]

In april last year one of my customers asked me if I would do this. She had neighbours either side of her who's children had trampolines, and they would throw a ball across her greenhouse as they bounced on their trampolines. Needless to say, but her greenhouse roof glass, got smashed. The parents said they would replace it, but they never did.
My first thoughts were as Al has already stated ... less light and less heat. Anyhow she insisted that less light and heat would not be a problem as any green house often has too much heat.
...
All of the glass was removed from the roof and the frame where the panes rest, scrubbed clean and washed down.
I then got four 3mtr sheets of 10mm twinwall polycarbonate from Wickes ( £21 a sheet last year). The only other item required was 3 tubes of adhesive suitable for polycarbonate and aluminium. (£7.00 a tube).
The poly was cut so it was a real tight fit. I did'nt cut it into the regular 24''x24'' pieces.But cut it 24''x 48''. I sealed the ends of the poly with the adhesive, and fitted end closure strips.
A bead of adhesive was laid down along the frame where the sheet would rest..
The ploy was then put in place and I fixed it with the original glazing clips.
Then the adhesive was used to double seal the edges going straight over the clips and onto the aluminium frame. It took me about four hours.
The client was really pleased as the temperature inside the greenhouse had risen by 10 degrees soon after the last panel was fitted.
Four months later I was called back as the customer had a problem. When I got there, she said that the problem was she did'nt know what to do with her bumper crop of tomatoes, the best she'd had in years. So she thought I should have some.
When I asked about how the polycarbonate had performed, she said it was better then having a glass roof as it let in less light, which meant she did'nt have to cover the roof with fleece....

[Ratty2E]

We have a polycarbonate roof on our conservatory. I don't know how long it's been up as it was here when we moved in, but at least 7 or 8 years. It doesn't show any sign of yellowing yet but I suspect that probably depends on the quality of polycarbonate you use. It does have a few dead woodlice that have ventured between the layers. I don't think the amount of light loss is a problem. In fact IMO I would say the more diffused light is better. It's fairly noisy in the rain but then if it's raining that heavily I'm off to another room and close the double glazed doors behind me and i can barely hear a thing.
If you are secondary glazing with it then it's not going to be any noisier than it is now infact the insulating layer would mean it was quieter.

[Matheous-2]

Thanks guys- plenty of food for thought there. My only concern would be the flies I think..... My other alternative was possibly getting the existing glazing tinted to cut down the light & heat....

[Ratty2E]

If it's insulation you want why don't you get blinds? They make them specifically for conservatories and they make them with a reflective matierial that can reflect heat out in the summer but help insulate in the winter.

[Matheous-2]

The problem with blinds rattyr.g. is that we recently spent about £400 on a very aesthetic looking internal roof curtain arrangement which is difficult to verbally describe.... In hindsight- yes, blinds would be a proper solution to the heat- but it's just deciding what to do now.....