DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Flooring (http://www.diychatroom.com/f5/)
-   -   Cheapest thinset for backerboard ok? (http://www.diychatroom.com/f5/cheapest-thinset-backerboard-ok-185989/)

jsunsun 08-26-2013 09:25 PM

Cheapest thinset for backerboard ok?
 
Hi all,

I'm looking to tile my floors that has plywood subfloor. I will be installing backerboard underlayment for the tiles (marble). To adhere the backerboards to the subfloor, is it ok to use the cheapest thinset I can find as shown here?

http://www.homedepot.ca/product/cust...y-50-lb/921779

The product description only mentions this for tiling over concrete (no mention of plywood), so maybe it may not adhere properly on plywood? However, I heard that thinset under backerboards is mostly just to fill the potential voids.

Will this thinset be ok for laying the backerboards? Thanks!

pgc555 08-26-2013 10:35 PM

THe difference between Custom and Versabond is about 10 bucks a bag. Use Versabond for both the underlayment and your tile

JazMan 08-26-2013 11:00 PM

Hi guys,

It's generally accepted that you can use a cheapo unmodified thin set for under concrete backers, but some want you to use modified. What brand backer will you be using?

You may not know, (?) but natural stone tiles require a much stiffer subfloor system than ceramic tiles do. I'm betting your subfloor is probably gonna fail minimum requirements. Just a wild guess. :no:

Tell us how the house is framed, type and size of joists, species and grade of joists would really help, joists' spacing, unsupported span. Also need to know the type, thickness and number of layer that make your subfloor/underlayment before any tile backer.

Jaz

jsunsun 08-27-2013 11:33 AM

1 Attachment(s)
The backerboards I'm using are called Wonderboards. The instructions made no mention of what type of thinset is required, it just says "apply mortar..."

Regarding whether the floors can support marble tiles: The subfloor boards are 3/4" thick. The joists are 2x10s, spaced 10-11" apart. Some parts of the floor have 2 ply 2x10s. The longest unsupported span (I-beam to exterior foundation) is 14 feet. I have no idea what type the subfloors and joists these are, but attached are images if that helps. Amongst all the houses I've "stomped" on, this house definitely feels amongst the most solid. Almost as if I'm stomping on concrete.

JazMan 08-27-2013 08:01 PM

Hi Sun,

Quote:

Originally Posted by jsunsun
The instructions made no mention of what type of thinset is required, it just says "apply mortar..."

Actually you must have missed the directions. http://www.custombuildingproducts.com/TDS/TDS-266.pdf

Use a polymer-modified mortar meeting ANSI A118.4 standards, such as FlexBond® Crack Prevention Mortar, for leveling bed and joint treatment; mortars meeting ANSI A118.1, A118.4 or A118.11 adhesive can also be used.


So it sounds like you're saying the unknown species and grade of the 2x10" joists are spaced 12" o.c. there are some joists that are sistered, and they span 14' 0".

It's not clear whether "the subfloor boards" you refer to are 3/4" planks or the plywood subfloor. It sounds like you meant the subfloor are 3/4" planks and there's 3/4" plywood over them. So, do you have two layers of subfloor? If so and they're in good condition, that's a good thing. :thumbsup:

So to sum up; if my assumptions are right, your subfloor should be stiff enough for natural stone tiles if installed correctly and still in good shape. The framing seems a little shy of min. specs but I can't say for sure without knowing their species and grade. I think you're very close if the joists are grade #2 and the species is Southern Pine. If everything else was fine, I'd do your install, but I would stress there would be no warranty against cracking due to subfloor deflection.

Jaz

jsunsun 08-27-2013 08:21 PM

Thanks! I didn't know there is a more detailed instructions other than what is on the board itself. I guess they do want a modified thinset, so I guess that rules out the cheapo thinset. Thanks all!

JazMan 08-27-2013 08:29 PM

They prefer a modified mortar but you can use a cheapo unmodified meeting A118.1 Be sure to follow instructions about the bond breaker tape over the subfloor seams and be sure to use the correct mesh tape for the CBU seams.

It sometimes isn't worth getting two type of mortar cuz you're likely to have partial bags left and the savings may not buy you a happy meal. Now if it's a large job, then.................

Jaz

jeffnc 08-27-2013 09:18 PM

Quote:

Originally Posted by JazMan (Post 1235080)
It's not clear whether "the subfloor boards" you refer to are 3/4" planks or the plywood subfloor. It sounds like you meant the subfloor are 3/4" planks and there's 3/4" plywood over them. So, do you have two layers of subfloor?

Look at his picture, which implies the subfloor boards are solely 3/4" plywood.


All times are GMT -5. The time now is 10:38 PM.


Copyright © 2003-2014 Escalate Media LP. All Rights Reserved