Converting pitched roof to flat green roof - advice?

[ohdiddums]

Hi all,

My 2-up 2-down has a ground floor bathroom at the rear with a pitched tiled roof. The room is very cold compared to the rest of the house because it has no roof insulation and a single skin wall at the back.

I'm trying to make my house as energy efficient, and eco friendly, as possible - and so my plan is to remove the roof tiles, get some roof insulation added, and then stick a green (sedum) roof on top instead of replacing the tiles. I've had a quote from a local builder which seems reasonable. He wants to brick up the wall to make it more level (not flat, but flatter) then add the insulation and sika sarnafil membrane, then the green roof. I just want to be sure the project is 'right'. Another friend thinks it's really weird to convert a pitched roof into a 'flat' roof and that the flatter roof might require a lot more maintenance than what I have now (not the green roof element...I expect to have to trim the sedum occasionally). Eventually I plan to get the single skin wall externally insulated too, but I want to deal with the roof first.

Any advice or opinions gratefully received.

Thanks in advance,

 

[freddiemercurystwin]

If you want to be as eco friendly and energy efficient as possible then the cost to demolish one roof to add another is both environmentally and financially unsound and any running costs you may save will take decades to recover if they are even recoverable at all.

 

[ohdiddums]

Thanks, maybe I shouldn't have said "as possible". Obviously I'm aware that it's cheaper and more environmentally friendly to do absolutely nothing, but that doesn't solve the problem of the very cold bathroom. And I don't expect the work to recoup its costs, just to make some energy savings while also hugely increasing the comfort level of the house.

 

[freddiemercurystwin]

Just adequately insulating would appear to solve the cold problem. And at a fraction of the environmental and financial cost of re-roofing with a flatty.

 

[ohdiddums]

Thanks, I'm just not sure how to go about that (without the works I've already described) - the roof doesn't currently have a void space to add any insulation into. And the ceiling is already very low, so that can't be internally-insulated either, because it can't go any lower than it already is. Similarly, the bathroom is too small to allow me to internally-insulate the single skin wall. And if I only insulated that wall externally, surely a great deal of heat would still be lost through the roof?

The side wall is a cavity wall, but I've already had this insulated without enough of an effect - too much heat is still leaking through the roof and single skin wall.

 

[Tigercubrider]

A couple of pictures would help but can't you open the pitched roof and add insulation then close the roof?