Solutions to strengthening loft joists - possible issue with span for boarding and storage

[Beete]

Evening all,

I posted this on the Screwfix forum but as a lurker on here also, I thought I would see if there was any additional advice that could be given.

Finally getting round to replacing the insulation and looking at strengthening the joists at the same time for storage of quite a few power tools and other household stuff that vary in weight. I thought that the joists overlapped at each span but I have discovered that they actually span the full width of the house - see attached photo of span and measurements. Current joists appear to be in good condition as far as I can tell.

Short of taking the ceiling down or other means and due to where the loft hatch is situated and the landing bannister being in the way, I am not able to get anything more than a 2.4m piece of timber up the loft. Tried a 3.6m piece but just can't do it although it might be possible to squeeze a 3m one with a bit of force but let's assume 2.4m only.

Any creative solutions to make this work? I have come up with a couple of ideas but not sure how sensible they are:

1. using new 45x120 or 45x145 timbers (If I can get away with 45x120 due to cost but if not so be it) join 2 pieces together using dominos and then sister the joint ends with at least 1m (or longer if it helps to spread the load?) either side of the join.

2. Rip 2 or 3 timbers equal size to current joists and bolt through all 3 and sister the butt ends as per #1

3. Same as #1 but double up either side of existing joist and bolt through all 3 timbers (is this overkill?)

4. Ceiling binder is in the way, can I notch over the top given the size of timbers I am looking to use?

5. I will most likely use any offcuts as noggins, if that makes any difference.


Also, I can't run a new frame with hangers off the brick walls perpendicular to joists because there is a Y frame in the middle of the loft holding up the rafters.

If the general response is that what I am looking to do simply won't work then I suppose I will have to make do with strenghtening up the joists on the shorter span but want to explore all options before I commit to anything.

Edit: Forgot to add the joists are at 400 centres

Cheers

 

[blup]

The current joust sizes are well below current standards so I would look to remove the binder, propping the ceiling to prevent sag and put in larger joists, widening or relocating the loft hatch to get them through, or breaking open the ceiling. Adding noggins might help but the ceiling was not designed for heavy storage. Double check if the mid span wall is load bearing, that will reduce the joist size.