# Ditra PM Advice



## angus242 (Oct 20, 2007)

I recently received this PM. I am going to start anonymously posting the PM questions so everyone can benefit:



> Angus, I'm hoping you can help me. I've been searching all evening to find out if 1/2 plywood subfloor, 2X10 joists on 12" centers is sufficient enough subfloor for Ditra XL and 12" tiles. Schluter info starts at 5/8" on 16" centers.
> 
> There is 1/4" ply on top of the 1/2 ply but I don't see it adding anything to support tile.
> 
> ...


----------



## angus242 (Oct 20, 2007)

This was my answer:



> Well you might not like my answer but you asked for it :laughing:
> 
> My opinion is a floor should be 3/4" T&G for a subfloor and 1/2" exterior ply for the underlayment. Ditra (standard) and tile. That would be over a properly structured joist system with a deflection ratio no worse than L/360.
> 
> ...


Please feel free to say what you would do :thumbsup:


----------



## PPRI (Oct 9, 2010)

You were very helpful I think. I still don't know why everyone likes the ditra so much. I really didn't care for it.


----------



## angus242 (Oct 20, 2007)

I have yet to find any other underlayment that is overall as good. I'm talking price, installation easy and material benefits, nothing comes close. :thumbup:


----------



## Paulie (Feb 11, 2009)

_Add another 1/2", Ditra and live long & prosper! _

Wow, I didn't know Vulcans used ditra too. Come to think about it I never saw a bathroom on the Enterprise, wonder if they were tiled.


----------



## JohnFRWhipple (Oct 20, 2009)

*Ditra over plywood*



angus242 said:


> I have yet to find any other underlayment that is overall as good. I'm talking price, installation easy and material benefits, nothing comes close. :thumbup:


I have stopped looking for a better system than Ditra for the floors.

My go to floor assembly is as follows;

1) 5/8 plywood subfloor or original 5/8 - 7/8 ship lap (often these sub floors are swiss cheesed while adding blocking or changing plumbing lines).

2) 1/2" plywood on top - glued and screwed to the Step One

3) Clean floor - rough it up - clean floor and prime 

4) Cable heat. 

5) Self level

6) Ditra

7) Tile and grout.


This system has worked for me the past 6 years and netted "Zero Call Backs"


The Romans had linear channel drains. The Romans used Sand Beds for uncoupling 12" - 20" thick. They also had Slaves.....

Ditra is lighter and most of my clients don't want a 12 " step into their bathrooms

:w00t:


----------



## CookeCarpentry (Feb 26, 2009)

I might have gone with a 5/8" exterior ply as the underlayment.

Unless removal of existing 1/2" subfloor was in the budget...

:thumbsup:


----------



## CookeCarpentry (Feb 26, 2009)

PPRI said:


> You were very helpful I think. I still don't know why everyone likes the ditra so much. I really didn't care for it.


Not to hijack the thread, but can you elaborate?


----------



## PPRI (Oct 9, 2010)

I mean I thought it was great for it's ease of use. It doesn't weigh a thing. It's easy to store and cut to fit crazy areas. I don't know if I was using to much thinset to set the stuff or what but it just didn't seem to get me as flat of a base as I am used to with concrete or hardi. I could tell where my knees were.


----------



## Splinter (Apr 5, 2005)

PPRI said:


> I could tell where my knees were.


I thought I was the only one that was bothered by this... 

I just grab a scrap of plywood out of the shop to kneel on now. Spreads the load out, no more potholes.


----------



## mr marble (Nov 3, 2010)

angus242 said:


> This was my answer:
> 
> Please feel free to say what you would do :thumbsup:


Why not wire mesh and sand mix?, you can go as thin as 3/8 min to what ever the desired thickness to meet at the door I'm assuming hard wood?, and if you need waterproofing , there is a roll on liquid most manufactures produce, and this combo is cheaper and stronger then schluter ditra mat yes it saves time but do the heights match ? Hmmmm lol


----------



## mr marble (Nov 3, 2010)

angus242 said:


> This was my answer:
> 
> Please feel free to say what you would do :thumbsup:


Angus I like that you use food products, awesome, but I have a great knowledge in the old school ways true, tried, tested for many years even centuries , there are pros and coma to the old and new , Rome was built with mud it's still there lol just a point !, your knowledge is great on the new products, but don't be so quick to dismiss old school ways my friend , don't take this the wrong way plz I'm not trying to criticize just reminding you old is food lmfao cheers my friend  by the way my real name is Jason , company name, Mr. Marble , p.show do I do mobile uploads with my I phone?


----------



## mr marble (Nov 3, 2010)

mr marble said:


> Angus I like that you use food products, awesome, but I have a great knowledge in the old school ways true, tried, tested for many years even centuries , there are pros and coma to the old and new , Rome was built with mud it's still there lol just a point !, your knowledge is great on the new products, but don't be so quick to dismiss old school ways my friend , don't take this the wrong way plz I'm not trying to criticize just reminding you old is food lmfao cheers my friend  by the way my real name is Jason , company name, Mr. Marble , p.show do I do mobile uploads with my I phone?


Sorry about the spelling damn spell check it puts what it wants , I have to start proof reading before posting lol sorry guys , great contractor but can't spell lmfao .....


----------

