Floor advice needed

[poynton phil]

Got a 45msq floor to do with porcelain tiles soon. The floor is floor boards,with a 5msq concrete utility room. The plan is to overboard with 6 or 10mm marmox and tile inserting a movement joint where the wood meets the concrete. Does this sound ok, or should i be thinking about using ditra as well. Any advice will be appreciated

 

[DHTiling]

Why marmox.. is there UFH being used..?

 

[poynton phil]

I meant hardie board, Dave, my mistake

 

[david campbell]

40m2 is a too big an area to tile without an expansion in my opinion no matter the dimensions here it is going to be longer than 5m2 in at least one direction

 

[Rob Z]

Hi Phil to add to what David said....one thing the engineers tell us in the seminars is that the movement joints should also be placed such that they divide the field of tile up into dimensions with ratio no more than 1.5/1.0. Ideal would be fields of tile that are bound by movement joints that divide the tiles into square fields, but this isn't always practical.

I see more and more masonry on buildings divided this way, with soft joints in the flat work and on the walls laid out in the ratio roughly 1.5/1.0 or even closer to 1.0/1.0. This is of course on jobs where there is enough money to pay for this work and where there are architects or engineers that are spec-ing this kind of detail.

 

[poynton phil]

Thanks for that info David, the room is 8m x 5m so i will fit another movement joint at around the 5m mark.

Thanks for that info too Rob Z, not to sure what you mean though, would appreciate it if you could explain it a bit more simpler, or give an example. As I'm a bit on the inexperienced side (or just thick)

 

[david campbell]

why not put it in the middle and work outwards from it so the floor looks symetrical
you don't need to go to the 5m point before it is inserted as long as there isn't a run of more than 5m

i think rob means to put tiles into squares of say 6 x 6,giving 36 whole tiles and have expansions surrounding it to give a more asthetically pleasing look

 

[Rob Z]

Hi Phil

If I knew how to draw diagrams with photoshop, I could post some on here to make it more clear.

What the engineering types say is that a floor that is a lot longer than it is wide, will experience more stresses (and uneven stresses) than a floor that is roughly square in the layout.

If a room is for example 8 feet X 24 feet, then for best practice the length of 24 feet should be divided into thirds with soft joints. This would then make three separate tile installations of 8 feet X 8 feet. As the tile experiences stresses from heat/cold, sunlight, floor loading and deflection, etc, the three separate 8' X 8' fields of tile will perform better than one field of tile 8' X 24'.

Most customers don't want to see anything going through the field of tile, not a soft joint material or Schluter Dilex or anything else. It's an uphill struggle trying to get folks to agree to this, but the facts are the facts and these are the recommendations from the engineers.

I try to get a compromise and get one in place, whenever possible. And I try to place them where they blend in, like in a doorway, or going under a island cabinet, or in some way that is less noticeable.

I have a kitchen/breakfast room floor coming up, and I'll place a soft joint at the end of the run of cabinets going to the back door. It will only be 4' long, but will nicely divide the two rooms without anything being too noticeable. It won't get the ideal ratio of 1.0 to 1.0 for each section of the floor, but will end up with the kitchen at about 1.5/1.0 and the breakfast room at 1.0/1.0.

I've never gotten a clear answer from Schluter about this, but I think for a warranty claim for Ditra, this is one thing they look for when evaluating a potential floor failure. I've had discussions with my local reps about this, but haven't taken the time to see what is said in writing in any warranty information.

 

[poynton phil]

Thanks guys i think I understand a bit better now. But like you say Rob, now its just a matter of convincing the customer, as he has just emailed me saying, he has decided to go with a opus pattern.

 

[Rob Z]

Hi Phil, I know this is a problem...diagonal layout, running bond, opus pattern, any pattern...and having a soft joint through the field of tile is no one's first choice.

I point out to customers what we see in shopping malls here. There are elaborate tile layouts running all over the floors, and like clockwork there are soft joints placed every X feet (based on what the engineer spec'd), and with no regard for the design. They do these things because they work, but don't always look nice.

Good luck with this big job you have to start.