[JazMan]

Hi,

Your joists should be fine for natural stone as long as they are in good shape and no one drill large holes or notched them. Installing blocking between the joists would be a good idea since the planks are not t&g.

I would have used 5/8" instead of 1/2", but still should be OK. What type and grade of ply did you use? You are not supposed to screw the underlayment into the joists, just to the subfloor. In your case you should have used screws that are 1 1/4 - 1 1/2" long.

Planning on using Ditra or 1/4" cement board.

I vote for Ditra. :thumbsup:

Can anyone ball-park the cost difference

The difference depends on what you'll be paying for Ditra. Generally I would say Ditra is worth 2x more.

Jaz

 

[Bud Cline]

In this case DITRA would be the wiser choice.

 

[allusionart]

Update

Well, the ply is 5-ply rated pine...actually just over .5" thick. The screws I used were indeed 1.25", only longer where I went into my joists (whoops). I can remove the ones in the joists if ya'll think it'll be problematic.

The joists are all cross-braced at the half way point, as far as blocking...all my utils run through there so I don't think its an option at this point.

I'm gonna run with the Ditra.

Thanks so much for your reply guys...

I have read much valuable information from you two on this site.