Vaulted ceiling joinery help

[richo106]

Hi All

 

Over the next few days I will be making a start insulating my vaulted ceiling

 

I want to 'flat' off the top of the ceiling so i can use this as a void to run cabling and MVHR ducting (I've attached some example pictures of what I mean)

 

Apologies for the daft question but I just want to double check...what is the best way to make sure these are all level and run perfectly in line?

 

And also the best way to fix them?

 

Many Thanks

[Bonner]

Some would say put a laser on it. Even though I’ve got one, would use a couple of string lines for a job like this!

[Iceverge]

Self levelling laser to get the correct starting points at both ends then a chalk line and snap a line. 

[Iceverge]

3 minutes ago, Iceverge said:

Self levelling laser to get the correct starting points at both ends then a chalk line and snap a line. 

 

I'm guessing since the insulation still isn't finalised this hasn't been done. Remind me  once you decide on that and I'll try do a sketch of an airtight detail for the apex with a good service void.  

 

 

[richo106]

29 minutes ago, Iceverge said:

 

I'm guessing since the insulation still isn't finalised this hasn't been done. Remind me  once you decide on that and I'll try do a sketch of an airtight detail for the apex with a good service void.  

 

 

No this hasn’t been done yet, this is my job for next weekend (if my tower turns up)

[Iceverge]

 

Have a look at this. 

 

Fit the cross member and fill above and between with batt insulation. Keep the 50mm clear for ventilation. 

Fix 2 x 95x25mm timber battens lengthwise below the cross member.

Then put a strip of airtight membrane below it to be returned to the PIR later on. You could put it behind the battens too but I think it might tear easier there during install. 

Fill any spaces that are too tricky for PIR with mineral wool. 

 

This will leave enough space for MVHR ducting and keep everything inside a continuous A/T layer. 

 

15mm plasterboard for better sound performance. 

 

 

 

 

[richo106]

34 minutes ago, Iceverge said:

 

Have a look at this. 

 

Fit the cross member and fill above and between with batt insulation. Keep the 50mm clear for ventilation. 

Fix 2 x 95x25mm timber battens lengthwise below the cross member.

Then put a strip of airtight membrane below it to be returned to the PIR later on. You could put it behind the battens too but I think it might tear easier there during install. 

Fill any spaces that are too tricky for PIR with mineral wool. 

 

This will leave enough space for MVHR ducting and keep everything inside a continuous A/T layer. 

 

15mm plasterboard for better sound performance. 

 

 

 

 

That is perfect! Thanks again @Iceverge