Loft support for store area

[dcoy]

Hello,

I have a question about adding support to my loft. I’m not planning on a complete conversion but want to make some space I can walk fairly freely about to put some organized storage on it.

My understanding is you should have 150mm joist probably no more than about 500mm apart to the put panels (18mm OSB, or ply or perhaps boards).

We have 100mm joists seemingly 300mm apart, then (what I believe are) 100mm hanging beams over the top with insulation between. These run pretty much the length of the attic with no noggins or other support.

I’ve seen on YouTube people building walkways with an additional 150mm on top of their ceiling frame, but this seems like overkill for my situation and would leave me with little head room. I’ve read about Sistering joists but likely too complicated for me. I’m thinking maybe if I put noggins in between the hanging beams and the 18mm ply over the top that might be enough(??) or perhaps a sturdy 100mm walkway over the top of the existing 200mm?

I would appreciate any suggestions how to go about this. The house is a 1930s semi in south London, I’ve added some photos (the previous owner put in a bunch of chipboard which seems more cosmetic and I’d remove before put anything on top.

Thanks in advance.

 

[Dereekoo]

What distance do your rafters span, what support walls if any are underneath the span of the rafters

 

[dcoy]

The length of the rafters is about 4.2m from the joists to the peak with a support beam running around the middle (around 2 meters)

I believe there are a few load bearing walls: one down the length of the house and 2 branching off ( existing open plan reno downstairs has replaced these with support beams).

I believe the diagonal beams in the below photo lead to the load bearing walls, I could be mistaken.

I hope this is informative.

Thanks

 

[Dereekoo]

Sorry I said rafters for some obscure reason when I meant the ceiling joists.

 

[dcoy]

No problem. A lot is under this chipboard, I’ve removed a couple of pieces to get an idea but not the whole. The space is about 5-6 meters square and the joists appear to be sistered. I can probably take a better look tomorrow evening, I’m away at the moment.