Conservatory / window insulation

21 Aug 2003
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United Kingdom
We are looking at improving the insulation of our conservatory. I'm going to replace the roof, but I want improve one of the side 'walls'. It is currently brick to knee height and then fully double glazed. As it faces our neighbours it is also frosted glass and we have blinds fully down permanently for extra privacy. My initial thought was to remove the glazing and fully brick it to the ceiling. My brick laying skills are crap and to pay someone else was looking expensive. So I wondered about the possibility of insulation board over the glazing. If we do it internally I then wondered about plaster board straight over the top of the insulation. Or I could put the insulation board on the outside of the glazing and then clad it with PVCu.

Just looking for peoples thoughts on:
a. is it worth doing just one side of the conservatory when we will still have two other fully glazed 'walls'.
b. is internal or external insulation the best option? Internal makes me nervous over condensation between the window and insulation. If internal I'd be limited to 25mm if we want to plasterboard over the top. If external we could probably go for 50mm.
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HI Lizzy,
If you replace the roof, you may be changing the nature of the conservatory enough to require permission for an extension. The definition of conservatory is the transpancy of the roof.

If you want to add insulation to the existig glass panel, then you'll need a way to combat the risk (likelihood) of condensation betwen the insualtion layer and glass by leaving a gap and venting it (to the outside preferably).

What I did to my conservatory was add an insulated ceiling that was completely internal. No change in the nature of the structure, no permission required. I made sure that I ventilated the roof space above the new ceiling with loads of small holes drilled in from behind the gutter. Then I added battens to the aluminium supports on the inside. After that I slid in some of the reflective insualtion that looks like bubbly packing material. After that I added the plasterboard.

I must admit that on the coldest and hottest days of the year, the conservatory is still uncomfortable. But it's much better and functional 90% of the time.

Hope this helps!
Daniel in Cambridgeshire.
How about just improving the frosted windows...triple glazed, argon filled etc. Its the quickest option. You could do this to all the sides!
Thanks for the replies. I have done the insulation on the inside of the roof, but I'm going to take it down as it makes our dining room too dark. That was why I was going to replace with the thickest clear Polycarb option (35mm).

Beefpotnoodle, What's the U value of the triple glazing?
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Air filled double glazing has a u value of about 2.2, dg with argon filled unit has a u value about 1.8. Triple glazing will have a u value about 1.2-1.4, and argon filled around .8! Bear in mind that the u value of your walls will be about .3
So remember if you put triple argon filled windows, the coldest point will now be your window frames, fyi
If the frames are the weak link is it worth spending all the cash on the upgraded glazed units?
New glass is cheaper than a whole new conservatory! Depends what you want it to look like and how much you want to spend

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