Back again...the things you do for love
I did a slightly more visual test by running some building line over a specific joist and put a 3mm shim for reference. The building line was 2mm at most.
So while the the movement looks bad to me (I really have no point of reference though), the visible deflection cannot be more than 1.5mm as at no point does the building line rise above the shim but you can see clear air underneath.
So if the allowable deflection over a 3ft span is 2.5mm (36/360) then the L value is more like L/720 observed.
If someone were tiling a
standard bathroom i.e. 8x2 joists, 10ft span and 16"OC then the allowable deflection is 120/360 which is about 8mm. I cannot imagine doing the same jump test on this setup would yield zero movement.
I'm still feel like some extra noggins or doubling up with the left over timber would provide some more assurances though I just dont feel like it would further reduce what I'm observing.
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