Insulate between doubled rafters?

[ToughButterCup]

Either side of the Velux in our roof, is a doubled rafter. Have a look:

 

There's a slight gap between them, one or two mm: not much, but enough to make me think that something needs to be done. One rafter has a slight twist in it....

• Foam?
• Bolt?
• Screw?
• Ignore?
• Foam and bolt?
• Get a life?

 

 

[PeterW]

Does the spec not say what should be done ..?? Either side of mine the doubles are screwed together and under the dormer cheeks it’s M12 bolts with washers etc

[joe90]

That’s my boy, attention to detail all the way. I would have thought bolting them together would get rid of the twist, make them stronger, avoid a gap and stop future movement. I am surprised bolting was not specified, ah crossed posted with Peter.

Edited May 16, 2018 by joe90
Cross posted

[ToughButterCup]

1 hour ago, joe90 said:

[...] I am surprised bolting was not specified, [...]

 

I'm not @joe90

Right, thanks, I'll get on with it. 

Now where's that @epsilonGreedy chap? He's full of beans at the moment. If you see him tell him to get his arse down here and do some work. 

[PeterW]

Bolts on smaller Velux windows and doublers are not needed unless you really go past 800mm width as it’s normally to support the trimmers top and bottom and the shortened or removed rafters. 

 

A coach screw every 600mm will suffice - nothing too difficult to retrofit. 

[Construction Channel]

Sorry I’m late. But this is the detail we use from our SE 

[ToughButterCup]

Thanks Ed.

On the list of things to this week coming. With a little luck this time next week, we'll be ready to felt and batten.

Meanwhile, there are loads of little irritations to finish off on the roof: if I don't get those done, they'll become more than mere irritants.

They'll be 'procrastinants'  a-la @Onoff

 

Good weather forecast, so all's set well for a productive week.

[Onoff]

On 17/05/2018 at 11:11, Construction Channel said:

Sorry I’m late. But this is the detail we use from our SE 

 

You don't use dog tooth washers between abutted joists?

[Nickfromwales]

6 minutes ago, Onoff said:

 

You don't use dog tooth washers between abutted joists?

The good old days mate. I've not had that specified for an age, really not necessary unless it's a super-diverse scenario. Wood is nice and uniform these days so a lot better than before ( the old sawn stuff ). For belt n braces I just glue as well as bolt. When the glues gone off you could prob take the bolts out as that's a lot of surface area bonded to the same. 

[PeterW]

18 minutes ago, Onoff said:

 

You don't use dog tooth washers between abutted joists?

 

I specified it for ours and used the bolts with the fixed plate and teeth in them - dead easy to do as a 1 man job. Like @Nickfromwales I also glued them as they were under the dormer cheeks. 

[Declan52]

Any I seen done just glued them up and put a few nails in them to hold it till the glue went off.

[Nickfromwales]

People underestimate how good a pukka resin based wood glue is. Try glueing two bits of 7x2 together and clamping for 48 hrs until completely dry. Then have a go, with your full tool kit, separating them. 

[ToughButterCup]

@Nickfromwales, @PeterW, @Onoff, glue spec, please!

 

Ian

[PeterW]

Standard D4.. the one you stick Egger floor down with is fine as it’s a polyurethane glue

 

Best one for old school is the powdered resin cascamite .... now that takes some serious abuse !!

[Onoff]

I like this D4 for general purpose stuff:

 

https://www.toolstation.com/shop/p61864?