250 to 300mm center to center
Under electrical code 368.56(B), flexible cords and cables can be attached to building surfaces. However, under electrical code 400.8, flexible cords and cables are not permitted to be dropped from a bar joist.
Drill a hole large enough and pull the cable through. The hole must be 1-1/2" from the edge of the joist to prevent nails or drywall screws from penetrating the cable. If the hole is less than this distance, a nail plate must be installed over the edge of the joist so when the wall covering is added, a screw or nail can't penetrate the wire. Any hole drilled through a joist must be no more than a fifth of the depth of the joist and should be as near as possible to the centre of the joist. Holes bigger than 30mm are not recommended without specifically designed additional strengthening to the joist.
Dan L. Wheat has written: 'Predicting the strength of wood-joist floors' -- subject(s): Floors, Wooden, Joints (Engineering), Wooden Floors
Anton Polensek has written: 'Static and dynamic analysis of wood-joist floors by the finite element method' -- subject(s): Floors, Wooden, Wooden Floors
A roof truss is a wooden frame for a roof, consisting of rafters and a ceiling joist. The shape of the roof truss determines the shape of the roof.
A joist is a beam, a supporting structure in a building. The roof joist was riddled with dry rot and had to be replaced.
Floor joist or ceiling joist? Floor joist have a board on the end all the way along the side of the building called a rim joist. Like the cross bar on the top of a T. Ceiling joist are nailed down into the top plate of the wall and to the rafters where possible.
it depen on the size of the joist
A 20 delta size nail should be used to attach the band joist to a joist when end nailing. A 16 D can also be used.
beam transfer loads from the joist to the wall or column where it supports..
There are several ways, but probably the easiest way would be to temporarily buck under the afflicted ceiling joist with a 2x6 temporarily, until the joist is in line with the others. Then go into the attic and cut and attach a 2x6 to the joist and vertically to the roof ridge. Remove the buck. The joist should stay in place.