Kingspan insulated roof, rain noise!

Sinnyoggy

Hi there,
This is my first time to ask a question on boards, bare with me if im not doing things right.

Im in the very early stages of planning an extension to a cottage. Im hoping to go with as much contemporary stuff as possible. My brief to the architect included a flat roof on the extension, as this was to the rear of the house & i wanted to keep the old look on the front of the existing dwelling.
When he sent me a draft drawing of the extension im after getting it into my head , that with a flat roof and possibly a low pitch the best thing for me, maybe is to go with kingspan or similar insulated panels, possibly building the carcess of the extension using a steel structure aswell.

My only real hesitation with the insulated panel is the rain noise that would come off it. Im just wondering has anyone any else had it fitted for domestic use?
The extension will be a single story, on a on elevated site.

PROJECT K

you would be much better off with a properly designed built up warm flat roof construction - yes you will get increased rain noise from a composite metal panel like KS and even though its to the back of the house, aesthetically it would ruin the integrity of the building. A clean contemporary flat roof extension would complement the existing cottage and will offer more flexibility in terms of internal layout (particularly ceiling heights). I would suggest the following build up:

Roof membrane (either PVC, Bituminous felt, liquid membrane) on
min. 120mm insulation (either bonded or mech fixed) on
high performance Vapour Barrier (all joints lapped and sealed) on
timber/concrete/steel deck

Make sure to have a min of 150mm parapet height. You can also lay the deck completely flat and use a "tapered" insulation system (i.e. where the insulation is manufactured to a slight fall, 1:60 would be best)

Goood luck with the project!
PK

BryanF

Do not taper the insulation as it adds €€€ - add firring timber pieces to the joists allowing sloped timber deck

and the insulation had better be in the 0.02wm2k range (ie a kingspan or similar not polystyrene)

Sinnyoggy

Thanks for tou replies!

Maybe i should have been a bit clearer, in my original post, as i said earlier its early days of planning & my arch has done a draft of 46'1 by approx 31' on the roof area. Its is on a south facing garden with the highest point of the roof to the opposite end of the existing house. The draft has included an over hang of approx 4' aswell over what plans to be decking or sheltered area.

Calahonda52

Sinnyoggy wrote: »

Thanks for tou replies!

Maybe i should have been a bit clearer, in my original post, as i said earlier its early days of planning & my arch has done a draft of 46'1 by approx 31' on the roof area. Its is on a south facing garden with the highest point of the roof to the opposite end of the existing house. The draft has included an over hang of approx 4' aswell over what plans to be decking or sheltered area.

Was fine till I read this
:eek:

BryanF

Calahonda52 wrote: »

Was fine till I read this
:eek:

Why?

I'd like to see the cost comparison, with say a build up roof. I'd be going for a very thick PIR panel.

Did you ever wonder about the joints in an insulated panel, 0.7mm of alu creating a linear thermal bridge, at say 1m intervals across a roof/wall, that could under the right conditions lead to condensation (where these panels are really useful there, is generally Mech ventilation).

Sinnyoggy

Morning, thanks for the input.

Am i allowed to post two pictures of houses that i have came across online that have similar styles to what im looking for?

BryanF

Sinnyoggy wrote: »

Morning, thanks for the input.

Am i allowed to post two pictures of houses that i have came across online that have similar styles to what im looking for?

You need 50 posts, put up the link minus the www. And the mods will update.