Carriage Bolt Double Floor Joist

Drill through the beam with a long bit the same diameter as the bolts.

Carriage bolt double floor joist. Starting about 2 inches from the edges of the beam counterbore two holes on the inside or the least visible side of the beam for carriage bolt nuts. Ideally nails should be used to temporarily set the piece and then either lag bolts or more preferably carriage bolts should be used to lock them together. Don t use lags because they will split the wood and weaken your lumber. It is much stronger than a lag bolt simply because the railing post is fastened on both sides whereas a lag bolt only attaches the post to one joist.

However shifting and settling can work these loose and separate the boards. I intend to glue and bolt a 50 100mm c16 timber to one side about 1 5 meters long and think it might be worth also fixing 18mm osb3 smart ply to the other mainly because i have an offcuts which will fit perfectly across 1 7 meter span and i figured this might add some further stiffness. The use of a carriage bolt with a simpson tension tie is ideal. I d use carrige bolts or through bolts nuts to bolt through the new full lenghth sister joist spacer joists and the original chopped joist.

You ll need a top and bottom bolt slightly staggered about every 2 feet to transfer the load to your new joists. When sistering these pieces together it is easy to put just a few nails in the boards and move on. Tension ties are connected to the joist using simpson sd 10 screws that are 1 long. If time or budget permits it would be nice to test some improper options like fewer fasteners than needed deck screws and maybe carriage bolts installed at an angle.

Floor joist testing. I would like to test nails lag bolts simpson sds bolts or similar and bolts with nuts.