Opinions on insulating this vaulted ceiling

[Aidy Gourlay]

I make it 7 complete, out of the 12 original, over the whole length.

Are all the windows poorly installed, or does it look like just the one with the extra rafter next to it?

 

[datarebal]

Can't see 7. At least 2 of the original are cut through by mistake I'd guess

 

[RandomGrinch]

Are all the windows poorly installed, or does it look like just the one with the extra rafter next to it?

Rafters are usually doubled, as are trimmers:

In your case they should run continuously from wall plate to ridgeboard.
Deviating from this practice is possible if structural loadings can be proved.

 

[Aidy Gourlay]

Rafters are usually doubled, as are trimmers:
View attachment 283523
In your case they should run continuously from wall plate to ridgeboard.
Deviating from this practice is possible if structural loadings can be proved.

Thanks RandomGrinch

So i could possibly run some new timbers from the ridgeboard to wallplate, to provide support fixed with screws?

 

[datarebal]

run some new timbers from the ridgeboard to wallplate

cut one put 2 back

 

[noseall]

Thanks RandomGrinch

So i could possibly run some new timbers from the ridgeboard to wallplate, to provide support fixed with screws?

Your biggest issue regards insulating is venting, which appears to be impossible with that roof layout. I'd be tempted to fully fill all voids with PIR, fill and foil tape, then add another layer beneath and across the rafters, fill and tape again.
You should double up the rafters each side of the Velux prior.

A hybrid roof is always risky especially for a kitchen. Robust attention must be paid to VCL.

Vaulty2

• noseall
• 15 May 2022

Eavesi

• noseall
• 2 May 2022

Foil3

• noseall
• 2 Apr 2019

Foil1

• noseall
• 2 Apr 2019

 

[datarebal]

Robust attention must be paid to VCL.

agree

 

[gonch69]

I also hope the ridge is fixed well cos now the collers have been cut out not much holding that in place plus think I only see one nail in the top part of that scab detail

 

[Aidy Gourlay]

Your biggest issue regards insulating is venting, which appears to be impossible with that roof layout. I'd be tempted to fully fill all voids with PIR, fill and foil tape, then add another layer beneath and across the rafters, fill and tape again.
You should double up the rafters each side of the Velux prior.

A hybrid roof is always risky especially for a kitchen. Robust attention must be paid to VCL.

Vaulty2

• noseall
• 15 May 2022

Eavesi

• noseall
• 2 May 2022

Foil3

• noseall
• 2 Apr 2019

Foil1

• noseall
• 2 Apr 2019

Thanks noseall, does this mean I don’t need a ventilation gap at all? Thanks!

 

[Aidy Gourlay]

I also hope the ridge is fixed well cos now the collers have been cut out not much holding that in place plus think I only see one nail in the top part of that scab detail

Hi Gonch,

I’d fastened the ridge with some 132mm concrete screws - assumed that’s sufficient?

 

[Aidy Gourlay]

Your biggest issue regards insulating is venting, which appears to be impossible with that roof layout. I'd be tempted to fully fill all voids with PIR, fill and foil tape, then add another layer beneath and across the rafters, fill and tape again.
You should double up the rafters each side of the Velux prior.

A hybrid roof is always risky especially for a kitchen. Robust attention must be paid to VCL.

Vaulty2

• noseall
• 15 May 2022

Eavesi

• noseall
• 2 May 2022

Foil3

• noseall
• 2 Apr 2019

Foil1

• noseall
• 2 Apr 2019

Thanks Noseall,

So I don’t need to worry about a ventilation gap with this method? Just insulate, exp. foam gaps and then tape?

 

[noseall]

Thanks Noseall,

So I don’t need to worry about a ventilation gap with this method? Just insulate, exp. foam gaps and then tape?

Basically yes. The awkward angles (bottom gaps) will be difficult to fully fill

 

[Aidy Gourlay]

Basically yes. The awkward angles (bottom gaps) will be difficult to fully fill

Will there be a risk of condensation if they’re fully filled?

 

[RandomGrinch]

Will there be a risk of condensation if they’re fully filled?

Yes, but as said before:

Robust attention must be paid to VCL.

If the VCL is as good as it can be, there won't be any moisture entering to create condensation.

 

[catlad]

They are poorly fitted skylights, the roof should have been rebuild really to accommodate those new skylights, how many are there?