Insulation Help - Flatroof

[johnnyjb]

Hi i was wondering could some one help me with my query?

I have a ground floor single story extension with a flat felt roof and want to insulate the inside ceiling.

I was thinking of installing insulated slabs and plastering , but friends have told me that it is easier to put rolls of insulation in between the joists and cover with standard plasterboard slab.

Is there must of a difference in insulation values in the 2 methods.

This is a diy job with a budget but would stretch budget if really need to

Also, if i was to use insulated slabs would it be recommended to remove the existing plastered ceiling slabs- or could i secure the insul slabs to existing plastered ceiling

Thanks

 

[lowCO2design]

1. I have a ground floor single story extension with a flat felt roof and want to insulate the inside ceiling.
2. I was thinking of installing insulated slabs and plastering , but friends have told me that it is easier to put rolls of insulation in between the joists and cover with standard plasterboard slab.
3. Is there must of a difference in insulation values in the 2 methods.
4. This is a diy job with a budget but would stretch budget if really need to
5. Also, if i was to use insulated slabs would it be recommended to remove the existing plastered ceiling slabs- or could i secure the insul slabs to existing plastered ceiling

1. is this roof sound and are you sure it will not need future work?and what is the exact build-up ([broken link removed] no connection I'm just point out the difference) ie is it felt on marine plywood on joists?
2. ill answer this once we clarify 1.
3. define 'much' in insulation terms. also are you installing a vapour barrier on the warm side? potentially in moisture terms yes and in cold bridge terms yes
4. you got answer 1 first & how thick are the joists?
5. yes, what height is your ceiling? have you the height? 2438mm or 8ft is generally considered the min