I have an old property which i am currently renovating. I have gutted the room which is to be the kitchen and have found that the existing floor joists(50x195-400 centres)) do not meet with acceptable span tolerances.The existing clear span is 6320 which is far in excess of the 4130 building code maximum - hence the deflection and floor spring.
I am toying with the idea of fitting a trimmer joist -consisting of two 75x195 joists bolted together- at the half way point, 3160, which will be inserted into the stone walls at either end and then the old joists jiffy hangered to both sides of this new trimmer joist.The trimmer joist has to meet a clear span of 5560(the width of the room) - i note that a single length of c16 75x195 has an acceptable span tolerance of 4680-will the two pieces bolted together give me the 5560 span tolerance required?
