On Jan 19, 3:40*pm, wrote:
I am a novice DIYer who is renovating a second floor bathroom. I
removed the subfloor to move some pipes and now that I am ready to
relay the subfloor I have discovered that one of the joists ( which
are 16 inches apart) and which is in the centre of the room has sagged
an inch. It has sagged where the first floor chandalier was attached.
I removed the chandalier and tried to pull up on the joist but it
won't budge.I am limited as to how much I can push up on the joist
from the first floor because I dont want to disturb the finished
ceiling.

When I lay plywood across the joists there is an inch gap between the
plywood and the one joist. I could proceed and screw the plywood down
and then use a levelling mortar to fill the trough, or I could place
shims *on the top of the 2x10 joist so that the plywood would lay
flat.What would be a good material to use as a shim? or how would an
expert proceed?
Brent
Thanks

I think you would get best results from Ken's approach. Attaching a
straight joist of the longest possible length to the existing joist
would provide enough extra strength to support the chandelier as well
as provide a solid level surface for the sub floor.

The sagging joist is probably the result of 'creep' resulting from the
unplanned for weight of the light.
Deforming the sagging joist without cracking it would take a period of
weeks at least.

T