Rafter tails being a pain in the Botticelli

[ToughButterCup]

Now that I come to look in detail at our rafter tails, I am beginning to realise that they were designed by someone who has never fitted the specified PIR in between any  rafters, let alone ours.......

 

First an empty rafter tail: the end in mind is fill it with insulation

 

 

Yes, you are right: each rafter has a double bird's mouth. The gap between the rafters in this case  is 318mm wide. The gap that needs filling starts at the wall (bottom of the image) and runs up to the noggin between the rafters.

The wall plate (sitting in its green polythene jacket) sits about 25 mm in from the inside edge of the wall.

 

So, I had a go: this is what I did;

 

Before you start applauding my master-craftspersonship, there's still gap at the back of the wallplate to fill. Grrrr.

 

This is the architect's illustration of the way the gap will be filled.....

I love the elegant way the PIR fits seamlessly over the wallplate.

 

The reason I am growling is that the gap between each rafter is a few mm different to the others.

 

So, 6 years from now, I will still be stuck on a scaffold shaving off a few mm here and there to fit the sodding PIR.

 

Please tell me there is a better way. By better I mean quicker. No is not acceptable 

 

The best idea so far I have had is to give Debbie some glue, a saw, some off cuts of PIR  , a safety harness and go for a walk......

[Construction Channel]

Personally I would cut the insulation like so. Still 2 bits but it should give a good chance of being tight against the wall plate. Also foam is your friend for this. You could piss arse about trimming every one but I would go for a standard size ( regularised 4x2 @ 400mm centres is usually about 355 iirc.) precut a bunch of strips then cut them to shape on the scaffold. With a roofing square it’s fairly quick to get plum and seatcuts marked, 

 

 

p.s welcome to my world ? 

[ToughButterCup]

Thanks Ed. Sounds like a job for SupeDeb 

 

I'll get some extra foam ordered......?

[Temp]

It would be tempting to over fill with insulation (horizontal sheets without foil) and run a hot wire down the rafters.

Edited May 22, 2018 by Temp

[Oz07]

As for widths all 15mm smaller and foamed into place. 

[PeterW]

Use rock wool to do the section over the top of the wall and then use PIR over the top to get the insulation as close as possible. 

 

Quick, cheap, simple and effective. 

[ToughButterCup]

10 hours ago, PeterW said:

Use rock wool to do the section over the top of the wall and then use PIR over the top to get the insulation as close as possible. [...]

 

That appeals, because we can insulate the 'back' (inside) with RockWool just before we insulate inside with more  PIR.

 

Thanks everyone for the help.

[Dudda]

Had a similar job myself. Took a while. The whole roof was stripped but the eaves first to allow me to continue the external insulation up over the wall plate.