Could joist bridging prevent movement and noise in my tile floor?

Question

Brand new tiles installed by contractor 4 years ago in kitchen, bathroom and also in a new house extension on pillars.  Tiles started clicking in the extension during first winter.  Now the grout is clearly starting to deteriorate.  Obviously the extension will need to be redone completely.
Since then a few tiles started clicking in the bathroom and in the kitchen but also only winter.
Subfloor information :

The house extension on pillars is brand new so I hope everything is repecting modern standards... which is weird because the problem is worst there!
In the house I have 2x8 joists with plank flooring and plywood on top of it. Don't know plywood thickness.

Since the problem is happening on two different types of subflooring I think the tiler somewhat messed up with the glue!
Questions :

Why it clicks only in winter?  Humidity, temperature?  There is a
big difference between winter and summer temperature here.
If possible I would like to fix the kitchen and the bathroom before it
gets worse.  Since the tiles click only in winter I am wondering if
bridging the joist could help.  If so, should I do it in summer when
it is not clicking?

jwh20 · Answer

The floor under your tile is moving.  Likely there is enough pressure from the joists in the summer to keep things relatively steady but clearly when things dry out in the winter there is more movement and you get the audible clicking.
The problem is that tile with grout is very intolerant of any movement at all.  The grout will quickly crack and start to pop out of the joints as you have seen.
No easy fix in my opinion.  Your contractor should have ensured that the floor was solid and without any movement before tiling over it.  It seems that was not done.
Now the best you can do without pulling up the tile and fixing the root cause is a band-aid fix.  Remove the grout and re-grout with a more flexible type of grout, such as latex grout. This will just extend the time until you have to do it again but possibly by then you'll be tired of this flooring and can have it done properly.
Some bridging MAY help but there is no guarantee.  It's worth a try at this point.

Lee Sam · Answer

No, adding bridging (or blocking) will not stop the movement that is causing your tiles to move and crack. In fact, it could cause more clicking and add noise to your floor. (More pieces of wood deflecting and moving.)
Bridging keeps the joists from laying over on their sides when overstressed. They do not help the deflection which is causing the movement (and cracking).
Obviously you do not have a problem with the joists laying over on their sides or they would have failed.
Often people suggest adding bridging or blocking to “transfer” the floor loads to adjacent joists. This is minimal, especially if you have a subfloor AND underlayment.
Tile floors require a very stiff structural floor system, which means the normal deflection of 1/280 or 1/360 should be increased to 1/720. Bridging will not do that.
You mentioned the noise occurs during the winter and not the summer. This could be due to humidity allowing the “wetter” winter joists to deflect more.
Rather, I’d suggest “sistering” another joist along side the existing joists to help stiffen the floor by decreasing the deflection. You didn’t give the composition of your structural floor construction, so I can’t tell you how overstressed the joists are currently, but you do not have to extend the new joists onto a support. Rather, I’d add another 2x8 joist to within 12” or so of a bearing point.

Could joist bridging prevent movement and noise in my tile floor?

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