External wall removal, roof support

[pkone]

I am adding a 2 storey extension where I need to install a 4 meter universal beam upstairs to sit directly underneath the roof plate.
I am looking for the best way to support the roof while installing the steel. It is a cut roof with a purlin just less than half way up.
I have thought about using strongboys under the plate, but they would get in the way a bit when putting in the steel, or across across under the ceiling joists and then putting in some extra timber between the joist and the rafter.
Also should I also acro the ground floor under the first floor acros, or would it be ok to spread the load across a few floor joists with boards?
Any help would be very much appreciated.
Many thanks.

 

[noseall]

If the rafters are birds-mouthed onto the purlin then why don't you prop the purlin?

Other than that, you could fix (screw) some timber sprockets that run vertically between the rafter and the ceiling joist, thus linking them together then prop directly beneath these.

The series of sprockets could be low down near the eaves and close enough for the wall plate to be useful but enough distance away to allow the steel to be fitted.

It may be wise to prop both at the purlin and eaves..

 

[^woody^]

Acro the ceiling joists which will hold the rafters, which are already held by the purlin

Load generally needs to go down the the ground floor via acros under the first floor, but you may be able to spread the load on the floor joists, you'll have to assess it and think about it

I'm curious why you need a beam under the wall plate if you are adding an extension, and presumably the roofs will join? Why isn't the beam in the roof space out of the way?

 

[noseall]

Acro the ceiling joists which will hold the rafters, which are already held by the purlin

You are assuming it is a modern roof with secure fixings.

I would be nervous about the joist detaching from the plate if the roof was somewhat elderly!

 

[^woody^]

I would be nervous about the joist detaching from the plate if the roof was somewhat elderly!

There is a solution to that .... hard hats!

Or wedge a length or two of timber in the loft between the joists and rafters were they meet down by the plate. And hard hats