Insulated plasterboard ceiling in a conservatory…(Good/Bad?)

My brother has just put a ceiling in his conservatory. Wooden rafters, plasterboard & plenty of insulation etc.
He reckons its now loads warmer, obviously.
Someone has told him the wood will rot away because of the condensation in there…
Anyone knowledgeable in this area able to offer any advice ?
Any building regs etc, that might need to be considered ?

Thinking of doing the same in mine as its a bloody deep freeze at this time of year.

I would have assumed that, given there is adequate ventilation, there wouldn't be a problem.

That sounds like a seriously daft idea. I'd love to know how he's attached it to the conservatory. Chances are he'll now get water pouring in. If he's drilled into the aluminium frame chances are rainwater will penetrate. It will depend on the roof as the level of ventilation. If he's got an Ultraframe roof there's a chance he will get decent circulation of air (it's designed in but still not perfect).

As for building regs, don't think there will be a problem there but conservatories are by their nature cold in the winter. That's why building regs insist on external grade doors between the house and conservatory. There's not a great deal you can do to make them significantly warmer. We are working on improving the insulation levels but it's not easy without making them incredibly expensive.

My advice is don't do it.

What are these wooden rafters held up by?

I'd have thought the only way to insulate a conservatory roof would be to use a spray on foam like sprayinsulation.co.uk. It sticks to the surface so condensation is unable to form, and is closed cell foam (unlike the aerosol cans of foam) so is unable to absorb moisture. But you would need to prepare the roof first as I don't think the foam is UV resistant, and also from upstairs windows the roof would look yellow 🙂

Bad idea. I would be very concerned about all that weight up there as conservatories aren't designed to take any stuctural loads, they are only plastic. (if someone tells you that they have a steel support rail in them, beware, those rails stop about 4 inches from any welded joint, ie top and bottom of each upright)

col

It's the roof that is the structural element in a conservatory and that is complete aluminium skeleton. That said it's not designed to take the weight of plasterboard and the low hanging weight will massively change the wind loading characteristics of the roof. If it's been put badly in the first place (nuts not put on bolts, not correctly anchored to the house, not attached to the frames correct, badly specced in the first) there's a good chance the roof will collapse 😆

If it is one our roofs, I really hope he dosen't try and claim under the warranty.

takisawa2

don't suppose you could post some photos of this construction, would be interesting to get the opinion of some of my colleagues.

Blimey.!!!
I'll pop round & see how he's fixed the thing in place. The conservatory is Wickes's UPVC one if I remember correctly. I recall him mentioning fixing a steel rail to the house wall to sit the rafters on.
Will report back. 🙂

I've done it, using insulated plasterboard, ie plasterboard with a polystyrene backing. It's made it a lot warmer, and removed a lot of condensation problems. We did it by making a frame of wooden batons and attaching the plasterboard to that.