Deflection resources.. "simplified" version..

[HomeDepotAssociate]

Now i know a few alarms probably went off when i used the word simplified.. or maybe not..
Could you guys either point me in the right direction to read about floor deflection? i know their was a thread on here somewhere but im having trouble finding it.. ive been meaning to learn up on it for a while but, well you know how that sort of thing goes!

I never bring up the issue of floor deflection with customers when im trying to get them started on their tile projects becuase A- i know nothing about it,
B- im afraid i might overwhelm them... which to be honest isint a good reason.

So aside from me doing the "heavy lifting" for them... if you were trying to explain to a diyer how to check thier deflection, how would you go about it? how much emphasis to place on checking this before tiling? and could you post links to good threads/thread on deflection? do newer homes usually have good floor deflection? we run tiles classes here usually every saturday if customers are interested and i think that would be a good time to address the issue briefly

thanks in advance

[bbcamp]

Try this thread.

[gsr]

There may be no easy way, it seems to be a complicated subject with a lot of variables. It's been said that the Deflecto calculator works because it's very conservative. I don't know how much advice you could give on the floor of the store without opening up a lot of liability. In any case...

Here are some maximum span tables:
http://www.awc.org/pdf/STJR_2005.pdf

and a more thorough discussion:
http://bct.nrc.umass.edu/index.php/p...g-span-tables/

When I need to check deflection I just go to the Deflecto (above). I guess you could just direct (all) your customers to the John Bridge site!

[HomeDepotAssociate]

Thankyou for the link to the thread

Yeah, it seems like a tricky one, especially to reciprocate to customers..
and actually i just went over some basics with a guy for our tile clinic and i strongly encouraged him to visit this site for questions he may have as he goes to do his floor. told him you are all very nice men and women and would be more than willing to answer questions he has and even correct some of my possible bad advice

Oh! One questions slightly off the thread subject but i wont spam and open up a new one;

If you have a floor that is plywood, mdf, and then vinyl

would you just need to pull up the vinyl, the mdf, leave the plywood and put down backerboard *or* could you pull up the vinyl and leave the MDF? NOw i know theirs probably going to be a lot of glue thier so maybe i've answered my own question.. but if there werent any glue thier (say it was loose lay vinyl), could you go over the plywood/mdf?

unless of course mdf is particle board.. (my intelligence is showing )

[Dave Taylor]

Kon asked:

If you have a floor that is plywood, mdf, and then vinyl
would you just need to pull up the vinyl, the mdf,

Yes and yes.

TYW folk don't usually recommend tiling over vinyl because.... it's someone else's work and.... may become the weak link in a floor sandwich supporting a ceramic or stone covering.

MDF (medium density fiberboard) swells tremendously when damp and (as such) is considered too unstable in a floor sandwich supporting a ceramic or stone covering.

So..... both vinyl and MDF should be removed prior to preparation for installing a ceramic or stone covering.

would you just need to pull up the vinyl, the MDF, leave the plywood and put down backer-board

Yes and no. It depends on the type, condition and thickness of the remaining floor after removing vinyl and MDF.

Often, after removing a vinyl covering and its' Lauan, or MDF, or particle board substrate..... it becomes necessary to add additional ply underlayment before applying cement board.

I hope this helps.

[HomeDepotAssociate]

Yes it does thankyou
could i ask you one more question then, would you need to add another sheet of plywood because of how the floor was originally (plywood+mdf).. in saying that.. i guess your changing the "structure" (for lack of a better word) of the floor so your going to need to add plywood to make up for the missing height? or strength?

[dhagin]

Have you invested in that TCNA Handbook yet?

Need to know what the structure is. Plug numbers into deflecto. Then need to know joist spacing. Then plywood thickness. Then whether ceramic/porcelain or natural stone. Also what tiling substrate are you planning on? Then what the substrate manufacturer requires under it.

BTW, most all this and more in that handbook.

[HomeDepotAssociate]

LOL
youi know what
i really need to go through that handbook