Advice on Upstairs Floor Joists

[Geoffrey Tuckey]

I need some advice/guidance on a possible issue with some upstairs floor joists. I am rewiring my house which is a pre 1940’s house. in one bedroom which is 5.5M long, the floor joists run the whole length of the room, at least i thought they did, however i have discovered that they only run half way from each end of the room and are nailed into two other joists running accross the middle and into the walls. my question is, is this ok? there are cracks in the ceiling below, which is obviously from a bit of movement. should i look at replacing the lot or am i just showing my lack of building knowledge, being a sparky!! any guidance would be appreciated.

 

[Dereekoo]

It is possible that the layout is structurally ok depending on the span, size, class of the cross joists and the fixing of the main joists to them. Doubt whether you could span 5.5m with standard wooden joists without excessive deflection.

 

[Worcesterman]

Just a guess, but if your ceiling and floor are still flat after however many years i am thinking it must be sufficient.