As the title states, in my roof I have what I believe to be called longitudinal bracing. It spans the whole length of the roof from end gable to party wall and is attached to the ceiling joists with nails. These are at the bottom of the trussed roof W but not attached to the trusses them self. It then has long metal brackets attached at each end. I’m wanting to fit a timber loft hatch and stairs which is perfect width but length wise I am being stopped due to this piece of timber in the way. My question is, is it ok to cut the section that crosses the hatch while leaving the rest nailed to the joists? I don’t want to be cutting anything if it is structural, altho I don’t see how it is really structural, but then I’m not a roofing expert, I’m just a very confident diyer when it comes to wood etc. I’ve attached pictures to describe what I’m seeing.
Those are bracing for the trusses and play an integral part of the truss structure. They stop the roof twisting or falling in winds. The ones attached to the walls brace the trusses to the walls and also provide stability for the gable walls.
I guess that answers my question about cutting the small section. Suppose a metal ladder is my only option as cutting and fitting ceiling the other side isn’t an option
Cut the piece of 4x1 you want to by all means, but do not touch the truss itself. The ceiling itself is acting as a brace across the underside of the truss cords, and that's without considering the stud walls tying everything together. It's good practice to fix a new piece the other side spanning two of the trusses either side of the area you cut, but nothing will fall down if you don't.
This was my original Idea if safe to do so, cut brace where red lines are. The remaining brace each side would be level with and still attached to the joists. (No joists or W trusses) would be getting touched. The blue line is where I was going to add a trim (noggin) Between the current joists for support and something for the new loft hatch casing to screw into and also where plasterboard would be cut for extending hatch.