covered outdoor deck is getting tile

[dbol]

We have a job coming up that is going to get tile on a covered deck. It has 3/4 inch plywood. What would be the best underlayment? Ditra for the waterproof aspect? Or just a cement board like Hardi? I think someone has recommended to one of the higher ups in my company that we should put cement board and Ditra down. Is this something to consider or just awaste of time. I think it is waste of time and money because wouldn't that be like putting down two layers of cement board.

[Dave Taylor]

You prollly seen Noble Company's blurb on their 'Noble Deck' product b4 but..... one recommended way to install it is to put it over CBU....

http://www.noblecompany.com/literatu...006-04%20L.pdf

[NVC]

Hi Doug,

I believe Hardie isn't rated or "is not recommended" for exteriors.
Wonderboard is, and I'd guess Durarock is too (verify the Durarock though)

hope this helps,
Mark

[dbol]

so would it be ok to put down 1/4 inch wonderboard and then Ditra because I don't think we can get noble from our distributors. I learned something else today. Thank you JB forum.

[Davestone]

Doug, what do you have for joists,this'll push you one way or the other,are they 16" apart,how big are they?

[dbol]

16 oc ,2x10, and maybe 16 ft. span

[Davestone]

They're not gonna support a tile job,Doug, according to the deflecto.You'd need to cut down the span with a support midway,somehow.You're good for almost anything exterior rated with the 16" width though.

[dbol]

Thanks, I'll check for sure tomorrow.

[dbol]

I checked the span and it is only 8 ft. Is ditra over 3/4" pressure treated over an 8' span ok for this deck

[John Bridge]

Hi Doug,

No one has mentioned whether the deck is over living space. That would make a huge difference if using Schluter products. I would check out the Schluter site and Noble Company, too.

I don't like the treated plywood unless it has dried out for about six months or so.

http://www.schluter.com

http://www.noblecompany.com

[bandstand tile man]

Doug, Nearly 7 years ago i tiled an outdoor deck with living space under it. I used schluter troba system with wonder board on top of it and for extra protection I sealed the top of that with laticrete waterproofing. Im much more experianced now and less nervous but the customer wanted to be sure it wouldnt leak and it never has leaked. by the way it was in the mid west were it gets hot in the summer and freezing in winter.
RIch

[dbol]

No it is not over a living space. My boss who kind of our lead installer will be installing 1/2" wonderboard, ditra and then kerdi on the seams and edges. Would it be best to install the kerdi on the outside edges and lapp them over the sides. the builder wil put a molding on to cover this edge. Oh yeah I will be doing the easy money part, installing the tile.

[T_Hulse]

Check out Schluter Bara trims. They're like regular "L" flashing that has a perforated top that allows a great bond to the Kerdi band. Don't let the homeowner/builder put any flashing on for you, it'll probably just have to be torn off.

Also veryify that the siding is being removed where the deck joins the house so that the Kerdi band can be adhered directly to the plywood, then the tar paper/moisture barier overlaps that, then the siding is replaced.

Here's a link to the Schluter handbook for balcony/deck construction. It has all the important details.

[dbol]

The deck actually is next to brick, which we will flash with kerdi band and then put on a peice of bullnose and use it as base.