Notching of joists
We've had 145 x 65mm joists put in for the first floor but they have had to be notched by 30mm on one end to get them to sit in a steal beam. Will these beams still be okay to support the first floor? Conscious it's over 1/4 of the depth of the beam.
Thank you in advance!
Replies from 9 tradespeople
NO
The max you can notch it is .125 x depth which in your case is 18mm.
Evan under IRC its .25
You should put a timber in the flanges of the steel beam and either fix it with tec bolts or drill the timber and steel and bolt it then use joist hangers-on for joists.
as described, it’s a concern and needs checking.
A 30 mm notch on a 145 mm joist is just over 20% of the depth, which is outside standard UK guidance if it’s at the bearing end.
Hello I would bolt a timber into the web of the steel & then use joist hangers to hang floor joists , then you are not taking any meat out of floor joists
Short answer: not okay without an engineer’s sign-off.
No. 30mm end notch in a 145mm joist too deep. Unless an engineer approves it.
Ideally get them to replace the joists or put them all on support wedges
The maximum depth of a notch should be no deeper than the lesser of 0.125 times the depth of the joist or 35mm.
The best solution is the bolt a timber in to the web of the steel and use joist hangers. I use this method if there is a height difference or too much to be notched.
