The architect has written 200mm first floor joists for a 2.6m room. But the rest of the house has 175 joists so does anyone know if that's ok for a. 2.6m span with today's regs? Thanks if you can help.
Fitting joists an inch thinner than specified
- Thread starter davidmiller
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You have not stated the width of said joists. My single mansard house has floor joists of 9"x 3" but it is well over 150yrs old when most buildings were erected to last. From my memory, 7" joists were fairly common not too long ago, but if your architect has stated 8" then they are what he requires. Before you challenge his decision, check with your local BCO.
175's at 400mm centres should eat that span.
hope he has specified a thickness, spacing and grade of timber as well
I'm not sure we can buy c16 anymore. Always stamped C24 these days.
170mm is slightly over specced. You'd need to be at maximum loading along with maximum centres to get close to the red line.
7x2 for 2.6m span?
That's absolutely fine.
Keep a standard 400mm spacing between the centre of the joists.
That's absolutely fine.
Keep a standard 400mm spacing between the centre of the joists.
I would double check with the architect designer, there may be a reason for the deeper joists. For instance are there any rooms with a wider span that need 200mm deep joists and he wants to maintain a consistent floor/ceiling level? Or maybe something concealed in the floor void such as a steel? etc. etc.
It can be risky to make an arbitrary apparent insignificant change without realising more important less obvious consequences that do not come to light until it is too late.
It can be risky to make an arbitrary apparent insignificant change without realising more important less obvious consequences that do not come to light until it is too late.
Agreed, but he probably just cut & pasted it from the last job! 
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They only sell c24 in my local yard these days.
Same with the green chipboard flooring.
Same with the green chipboard flooring.
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