Loft Conversion advice. Purlin strut removal.

[SpaceWorm]

So you want to attach a ledger board to the spine wall on each side and sit the joists on hangers is that correct? You need to be careful with this arrangement with a single skin wall (assuming it is single skin) as this causes eccentricities and reduces the vertical load capacity of the wall.

If your are using this method, does that mean you will be building up the wall so the underside of the new joists flies over the existing ceiling joists, given the run perpendicularly? Or is it already the correct the height to do this?

 

[Poe]

The wall is single skinned.

I wasn't planning on building the wall higher (with bricks).

I was think of two ways to fix the new joists here.

One would be to sit the joists on top of the existing spine timber wall plate using longer timbers to form an overlap and sister the overlapping ends.
The joists would sit approx 3 inches higher that the ceiling joists or perhaps notch the spine timber to drop the joists lower if that's permitted.

Or the second idea was build up the spine wall timber to the right hight using new timber fixed on top then use a deep wall plate (ledger plate) to sandwich the old and new spine timbers using threaded bar passing through both the new wall plates each side.

Poe

 

[Poe]

Still waiting to here back from the last two structural engineers that told me they would get back to me with an idea of costs and arrange sure visits!!

I'm the mean time thought I would post a couple sketches of how I see the joists fitted to the spine wall and the old top purlin struts re-supported with a doorway.

I understand the concern about excessive loads on the spine wall but obviously the engineer will take this into account, I'm hoping loft rooms carry less loads than other rooms considering the angled ceilings.

To be honest a single room over the larger bedroom with a stairs coming out of bedroom 1 would give us a four bedroom house with three of them being a decent size.

The rest of the area over bedroom one could just be attic storage. Obviously not supported off the spine wall.

Cheers Poe

 

[RonnyRaygun]

You can completely remove the top purlin struts rather than leave a section of them, once you've got a stud underneath the purlin and the brace in position.

 

[Poe]

Hi RonnyRaygun,

Thanks for that, hopefully I will eventually find an engineer who will actually want the work here.

If this is all to much for the spine wall it will have to be some form of beam running gable to party wall and purlin/dwarf support walls off these.

I just need to know what is or isn't possible first.

Cheers,

Poe.