Making a false ceiling

[marsaday]

I have an attic roof to insulate, but i see little point in insulating the top sloping section. instead i will create a level false ceiling. The purlin which spans the room is perfect for building off. i then need to add a wall plate on the opposite wall.

Above the ceiling will be rock wool insulation and under it, 50mm kingspan and plasterboard.

the span is 1.5m.

1) What size timber do i use for the wall plate and can i use screw and plugs or do i need to go for rawl bolts?

2) What size timbers will i need ? Are 4x2 ok?

i also need some advise on the section section of the ceiling which is sloping and falls between 2 purlins. The span here is 2m and i want to again create a false ceiling, but this time go with the shape of the roof. What size timber do i use here?

i will sit the timbers on joist hangers and cut them to fit. Kingspan will be placed between and under them and then finished with plaster board.

if you are not sure on what i am trying to do i can explain more.

 

[Deluks]

Not quite clear, but 4x2 will do for everything. If you are attaching to the sloping rafters then fix insulation then plasterboard directly.
Large screws n plugs will do. Better use long frame screws, which go into the brickwork without any plugs.

 

[marsaday]

the sloping ceiling still has the old plaster on it. will it be ok to add insulation and a new layer of plaster board. Will the weight be an issue.

Are the long frame screws those which you use on fixing pvc windows ?

 

[marsaday]

Ventilation question:

should i drill a Vent hole for the void above all the insulation and ceiling? Is there a need for ventilation up there? I will tape up my new roof with a VB.

 

[noseall]

Why have a false ceiling when you can have a genuine one?

What is a 'false' ceiling?

I prefer the term suspended or lowered.

Just being a pedant, sorry.

 

[marsaday]

lowered then.

what is the point in heating a space 4 m high? if i put in the lowered ceiling i will be creating a ceiling about 2.6m high.

 

[Deluks]

You won't have any probs if the vapour barrier is maintained. Yes, sound like window fixing screws. Like these.