First Floor Service Cavity?

fredgalway

We do not use insulated slab. We use 80mm foil back insulation taped with air tightness tape, this acts as air tightness layer we then slab over. This is what we have being doing for a number of years. I think it still be okay going forward but not 100% sure.

fclauson

Barney - from the top down

• boards supported on timber verticals to joists (for supported loft storage space)
• 500mm of blown cellulose (it "flows" around joists which rolls of stuff never will)
• membrane stapled to underside of joists and taped at all joins and perforations - attached down walls and glued
• 180mm service voice using metal suspended ceiling
• plasterboard

in one central place have (from bottom up) for you cables

• plaster board
• service cavity
• membrane
• plywood square - say 2ft by 2ft - through which you run your cables - one hole per cable - and seal around each cable - glue board to membrane as well
• insulation

at outer perimeter of build see attached drawing - all rights reserved by its author

fclauson

fredgalway wrote: »

We do not use insulated slab. We use 80mm foil back insulation taped with air tightness tape, this acts as air tightness layer we then slab over. This is what we have being doing for a number of years. I think it still be okay going forward but not 100% sure.

just 80mm ??

BryanF

fredgalway wrote: »

I think it still be okay going forward but not 100% sure.

you seemed sure enough that a service was not required?

fredgalway

Yes Bryan I am sure a service void is not required now, what I said was that method used by us is fine now but not sure if this will be case going forward.As regards the 80mm insulation to underside of joists this is in addition to insulation between joists and is above what is presently required.

BryanF

fredgalway wrote: »

We do not use insulated slab. We use 80mm foil back insulation taped with air tightness tape, this acts as air tightness layer we then slab over. This is what we have being doing for a number of years. I think it still be okay going forward but not 100% sure.

fredgalway wrote: »

Yes Bryan I am sure a service void is not required now, what I said was that method used by us is fine now but not sure if this will be case going forward.As regards the 80mm insulation to underside of joists this is in addition to insulation between joists and is above what is presently required.

just tot be clear, are you the general contractor, the ceiling subbie or the air-tightness subbie?

fredgalway

Bryan I find your attitude a little puzzling to say the least. The question asked by the op was asking if a service cavity was advisable. you have given your opinion as have I. Why do you feel the need to question me as regards my occupation, surely we are allowed to have opinions regardless of what we do. I am disappointed by your attitude.

fclauson

fredgalway wrote: »

Yes Bryan I am sure a service void is not required now, what I said was that method used by us is fine now but not sure if this will be case going forward.As regards the 80mm insulation to underside of joists this is in addition to insulation between joists and is above what is presently required.

How air tight had this approach prooved to be ?

893bet

fclauson wrote: »

• 180mm service voice using metal suspended ceiling

Any more info on the above or perhaps a link or PM about the product you used for the suspended ceiling? Images?

• plywood square - say 2ft by 2ft - through which you run your cables - one hole per cable - and seal around each cable - glue board to membrane as well

Makes alot of sense!

fclauson

check out the following for the suspended roof

https://www.facebook.com/photo.php?fbid=165904420281337&set=pb.154344008104045.-2207520000.1387842905.&type=3&src=https%3A%2F%2Fscontent-b-ams.xx.fbcdn.net%2Fhphotos-ash3%2F574662_165904420281337_1202211607_n.jpg&size=960%2C720