I would appreciate some advice on a joist cut I need to make to enlarge our loft hatch opening to accommodate a new hatch/ladder combo.
The picture below shows the existing opening and the red line shows the proposed opening. As you will see, I need to cut through joist A at the top of the picture. (perhaps ignore the 2 pale wood pieces coming of that joist on hangers - that was me attempting create some support, but I sense this might be the wrong approach!)
Here is shot from below if it helps:
Also, I thought it's worth sketching out the odd shape of the house:
My question is, can I cut this joist, and if so what support do I need in place?
Do I need to remove the existing trimmers and then hang new trimmers off the intact joists either side of the gap as per the thick blue lines below?:
If I were to do this would I need some temporary support in place in order to remove the old trimmers and cut the joist?