Suspended Timber Floor Tile Prep

[Deyna]

To be honest I've spent the last couple of nights poking and prodding and even with the extra walls its just not good enough...

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Even with overboarding again I don't think this can be eliminated or at least reduced to an acceptable level.

 

[Deyna]

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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[Perry]

Put a full glass of water till its convex. Then jump on the floor. if it OK the floor will be dry. That's the old way.

 

[Deyna]

Put a full glass of water till its convex. Then jump on the floor. if it OK the floor will be dry. That's the old way.

Ye I did that. It didnt spill!

 

[Perry]

That's what I have always used never had a problem yet in 35 years.

 

[Deyna]

I did however spill my beer last night after foolishly putting it on the floor. Didnt even have a sip :/

 

[Andy Rhodes]

What you need to ask yourself Denya is can you live with the 1.5 mm deflection, because if you can you answered your question you asked us all & all this has been possible because of all the good information you have provided us with

 

[Deyna]

@Andy Rhodes Thanks fella, you guys have helped massively. Like I said its hard not having a point of reference for what is acceptable. I feel more confident given the additional steps I took on everyones advice and I am happy to take this risk now. The overboarding with cement board removed any flex in the ply as well.

 

[Andy Rhodes]

Advice is always free, it's nice to be nice

 

[Deyna]

So heres my progress...

Had to use the levelling clips due to slight bend in the tiles would not have managed to lay without lippage so something to be mindful of when evaluating plank tiles next time.

Unfortunately I think they are expensive junk (the clips) but in this case a necessary evil to get a good finish. I found that probably 80% of them snapped incorrectly so I'm using my multitool with to grind them down to where they should be. Obviously this is due excess adhesive squeezing up around the clip when putting the tile in place but it seems difficult to find a balance without leaving voids around the clip areas. Didnt feel like I had too much addy though so I will need to find a solution for the extension as I wont have the patience to make good such a large area!

Again, thanks guys for the help. Had some good fortune with end of tile landing right on the pipes so saved me taking the rad off 🙂