Hi all, sorry this is so long, hope you read it and can advise...
I'm rebuilding a floor that was way too bouncy. 90 x 55mm old joists are being replaced by 8 x 2s (span 3.4m). The house is a brick mid-terrace. The plan is to chemically anchor legdgers/trimmers(?) to the front wall and the central wall and run the joists between them. However the front wall has a bay which I can't fix above. The bay is 1.8m wide. The wall to the right is 1.4m and to the left only 380mm - (this is basically the depth of the alcove of the chimney breast on the party wall.) So, I have doubled up on the front wall ledger/trimmer in order to span the bay.
So far this is what I've done. I joined a long timber for running across the front wall at right angles to a short one (750mm - for returning into the alcove on the left) - like an 'L' shape. I used 5 x 100mm TimberLok screws running through the face of the short timber into the end grain of the long timber. I then fixed this up on the walls. I used 12mm threaded bar, chem anchored into the wall in 5 places to the right (1.4m) and 2 to the left (380mm). The short timber is anchored in 4 places.
Then I repeated the pattern. I've put another 'L' shaped connection in front of the first one, in effect doubling them up. The front timbers are then attached to the back using more 100mm TimberLok screws. I've used 22 (two rows of 11) on the long timbers (250 - 400mm spacings) and 8 on the short (180mm spacings).
So if you've followed that I'd like to know if you think it's enough. Are there enough chemical anchors? And can I rely on the TimberLok screws? I read somewhere that they are the equivalent of M10 coach bolts, so it seems to me to be well over engineered, but....
Thanks for all comments, Paul
I'm rebuilding a floor that was way too bouncy. 90 x 55mm old joists are being replaced by 8 x 2s (span 3.4m). The house is a brick mid-terrace. The plan is to chemically anchor legdgers/trimmers(?) to the front wall and the central wall and run the joists between them. However the front wall has a bay which I can't fix above. The bay is 1.8m wide. The wall to the right is 1.4m and to the left only 380mm - (this is basically the depth of the alcove of the chimney breast on the party wall.) So, I have doubled up on the front wall ledger/trimmer in order to span the bay.
So far this is what I've done. I joined a long timber for running across the front wall at right angles to a short one (750mm - for returning into the alcove on the left) - like an 'L' shape. I used 5 x 100mm TimberLok screws running through the face of the short timber into the end grain of the long timber. I then fixed this up on the walls. I used 12mm threaded bar, chem anchored into the wall in 5 places to the right (1.4m) and 2 to the left (380mm). The short timber is anchored in 4 places.
Then I repeated the pattern. I've put another 'L' shaped connection in front of the first one, in effect doubling them up. The front timbers are then attached to the back using more 100mm TimberLok screws. I've used 22 (two rows of 11) on the long timbers (250 - 400mm spacings) and 8 on the short (180mm spacings).
So if you've followed that I'd like to know if you think it's enough. Are there enough chemical anchors? And can I rely on the TimberLok screws? I read somewhere that they are the equivalent of M10 coach bolts, so it seems to me to be well over engineered, but....
Thanks for all comments, Paul
