Weird joist layout

[joe384]

Hi,

Not sure if this should be the Building forum or the Floors forum...

While trying to run ethernet around my house I have come across a confusing situation and since I am not a builder it has got me a bit concerned.

It seems one of my joists ends mid span and then from then there are some joists spanning over 1200mm

I have attached a picture, H are joist hangers N are screws (?) Uncompleted parts just mean I haven't investigated that part



There are 2 issues I now have:

1) I have drilled 2 x 25mm holes (pink lines). I was trying to keep to the span guidlines (0.25-0.4) but I may have messed some of the them as I didn't realise the horizontal joists were spanning over the space of 2 joists.

2) Is this wrong from a structural perspective? Surely span tables are irrelvant now for half the floor as the joist ends and there is now blocking where the joist should continue on.

 

[blup]

Needs further investigation if you are not sure but..

If the side to side joists are sitting in hangars on front to back joists should be OK if the front to back joists are adequately supported on the wall plate of the dormer. Not really clear from your description.

Blup

 

[joe384]

I am assuming the front to back joists are supported by the front wall at the front of the house, at the back by a beam that goes across the house.

The side to side joists are clearly supported by joists which are 1600mm apart so I don't know how the loading calculations would work it a siuation like that.
Joist span tables assume the joists are spaced 400mm to 600mm not 1600mm apart!