Sorry to hear this. Sounds like it was very unexpected and going to cause some pain. I cant help with any advice on the joists and so forth.

 

However from an engineering perspective, its worthwhile to stop for a second, stand back and look at the situation and make a plan to get you to the end and ensure it's all done correctly.

 

If you have all the materials you need and you're not down and cash because the builder had an advance payment then you're in a good place and could look at getting someone else in.

 

If they've walked off with your money...then there are always channels to get it back through the proper processes, which can take time. 

 

I would definitely take the time to try and put all the drawings in order and find any you dint have if after all you've paid for a design and SE they should be available. 

 

Hopefully of some help. 

28 minutes ago, SuperJohnG said:

Sorry to hear this. Sounds like it was very unexpected and going to cause some pain. I cant help with any advice on the joists and so forth.

 

However from an engineering perspective, its worthwhile to stop for a second, stand back and look at the situation and make a plan to get you to the end and ensure it's all done correctly.

 

If you have all the materials you need and you're not down and cash because the builder had an advance payment then you're in a good place and could look at getting someone else in.

 

If they've walked off with your money...then there are always channels to get it back through the proper processes, which can take time. 

 

I would definitely take the time to try and put all the drawings in order and find any you dint have if after all you've paid for a design and SE they should be available. 

 

Hopefully of some help. 

thanks, and arguing over delivery of rest of materials we have paid for... TBF I was on site every single day; evenings in the week and all weekends. I know that building inside out! I have every drawing, in fact the architect and SE based the design on the spec I gave them. but detailed drawings they are not. I just need to work it out in my head. If we end up 25K down it will be a result...…. next few days will tell, in the meantime I fixed up a roof steel this evening, 6M long and bloody heavy (not very big really 203 by 101 UB 23, me and my 19 year old manhandled it round, into the building and onto the tops of the walls.  The steels were the complicated bit really!

The reason I asked about SEng designs is you said you had no more hence the query on the joints. 
 

Ok so if you are going it alone then you need to work smart. Have you got a proper steel framing square as you will need it. Use that to make a jig for the wall panels so they end up plumb and square, do not trust that the sheets of OSB are perfect and check every one.  
 

For safety, you’re going to need to do the upstairs floor slightly differently - fit enough joists to allow you to lay temporary floor panels, if they are 400 centres that will be a minimum of 14 from below and then fit a board either end and woot off that. Keep laying and fixing the boards temporarily, but don’t be tempted to jump between them or slide boards around to work on. 
 

I’m assuming this is all nailed together ..?  Paslode..?

 

I'm a bit out of my depth on this one compared to some of the practical advice that you are getting from the usual hero's on this forum. One thing though, I would go back and edit / redact those drawings you posted up on the last page. They have your name and building site address which probably isn't great for security etc. Good luck getting sorted with the build.