Tiling vertical post

kellyharris15

I am remodeling an old house I bought about 8 months ago. One of my ambitious ideas was to tile a vertical wood post I built to seperate my kitchen from dining room. I successfully tiled and grouted the whole post, which goes from floor to ceiling. The grout lines are about 1/4 inch wide. The tiles are 12x12 slate (cut to size). I completed the post about 3 months ago and it has looked beautiful with no concerns at all until 2 days ago. I happened to look closer at it and noticed that along both main sides of the post the grout lines had completely separated and cracked. I pressed on a few of the top tiles on the narrow side of the post and they fell right off. I looked even closer and noticed that almost all of the tiles were no longer solid on the post...the mortar has separated and the tiles move to the touch. This house was built in 1910 and there is a sagging section of the floor below the post in the basement. I had noticed this before but assumed it had sagged as much as it was going to...

1. Is this directly related to the potentially sagging floor below the post?
2. Could it be more related to my inexperience with tiling...maybe using the wrong mortar, grout, trowel, etc...? (It held up for 3 months with no issues at all)
3. Could it be related to cold weather? (The post is by my back door which is my primary door and is opened and closed a lot with the cold air coming in. My house is kept at at least 65 degrees usually, but does get down to about 60 at times.)

I bought a steel support to hoist up the sagging floor from the basement. I plan to lift it up over the course of the next few weeks then go from there.

Any advice would be a great help!

Thanks

Boostedfdrx7

First off your grout joints are a little thick for walls. If you like the wide joint look, then I would use some type of latex grout or epoxy grout. I keep my grout joints right around 1/8" to 3/16".

Next, what type of mortar are you using to stick the tiles to the post? also are you applying the tile right to the wood or do did you put up concrete board between the post and your tile.

I dont think that sagging is your problem. like you said, the house has had a long time to settle. and the cold weather wont affect it either. The only way weather would affect it is if you have alot of humidity by the post. moisture can get in the cracks of the grout and separate the mortar from your posts. thats where the cement board comes in handy

kellyharris15

Thanks so much for replying. Everything you mentioned makes a lot of sense. I used a general purpose mortar for the tiles. I was advised at Lowe's that the mortar for the project would not matter. However I did use sanded grout for the joints, instead of latex or epoxy grout. Also, I mortared the tiles directly to the wood beam I built. I did not use any kind of cement board between the wood and tile. These are things I didn't even think of.

kellyharris15

In your experience would making these changes you suggested make the tile post durable and long lasting?

Thanks again for your help

Boostedfdrx7

yes these changes would make the tile last not just a few years, but decades. the tile is not going to add any structural strength, so the tile should last as long as the post will. I dont know if your using premix thin set or not but a good quality thin set can go along way. I do appreciate lowes and home depot, but not all of the department people know what they are talking about. When in doubt always remember you get what you pay for, especially in materials.

kellyharris15

Great. Thanks again for your advice!

oh'mike

Tile over wood will frequently fail--wood expands and contracts more than the tile--breaking the bond.

Time to take it down---screw or nail 1/4 inch Durrock or Wonderboard--onto the post first--
Then apply the tile with latex modified thinset-( powdered)

That should do it---The grout width is a matter of style--and has nothing to do with the failure --

Good luck--have fun---Mike--

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kellyharris15

Thanks oh'mike for the advice. I do plan to take it down and start over. I will definately use the wonderboard, I've heard good things about it.

Do you know if the type of grout used makes a difference? I used sanded grout and have heard that maybe I should have used a latex or epoxy based grout since the tiles are vertical..

Thanks again

chinablue

I'd like to do something close to what Kelly did. I have two 4x4 support posts supporting my outdoor lanai roof that I would like to tile. They do not get direct rain on them, but they are out doors in Tampa, Florida and they are already painted. I don't want to tile the whole post..just about 3 feet from the ground up as an accent, since I'm having my pool re-coated and cement re-cool decked.

I'm not an experienced tiler, but I do know that cement board is usually recommended and I'd like to use small mosaic tiles. Can I use a bull nose tile to cover the edge and some sort of construction adhesive to finish off the top edge? Any tips from the experienced masters here would be greatly appreciated!

Thankz,
China

Bud Cline

First the posts should be covered with a minimum 3/8" exterior plywood, then cement board, then tile using modified thinset tile mortar.

chinablue

Thank you Mr. Cline.
Can I ask why the plywood is necessary if I'm using a cement board? I really didn't want to change the profile of the post making the bottom any bigger than what the cement board and tile will already do...

Bud Cline

The ply may not be totally necessary but all dimensional lumber moves and the plywood will help to stabilize the posts expansion and contraction. You can try using just the cement board but what you are doing is "trying" it. Better safe than sorry in my thinking.

chinablue

Thank you again sir for taking time to reply. I can hear my Dad saying..."Do it right or don't do it at all"

I will attempt the plywood. Wish me luck!