How much expansion should be allowed for 1600 sq ft?

[tileam2000]

Im tiling 1600 sq ft of 18" porcelain over a concrete slab in Florida. I will be taking the baseboards off prior to install and will try and make the floor as flat as possible for the money. How much space from the walls, and cabinets should I allow for exansion? Obviously a floor this big will have some movement. The slab is about 10 years old.

Also, currently there is about 750 sq ft of the existing original tile and the rest carpet that will need to come up. A lot of the existing tiles are hollow. and I see one big crack that runs the the grout joint from one end of a room to another (tile is run straight). Im guessing there is probably some sort of exansion joint/cold joint in the slab and the original tile mechanic layed out the floor based on this joint. The customer hasnt determined if they want the tile run straight or on a 45. If they run it on a 45 degree and there is a exapnsion joint in the slab would you recomment transferring the joint into the tile and putting a soft joint (caulking) in to fill....and if I run the tile straight should I lay my floor out so that the grout joint falls on the exansion joint (if the exansion joint is square with the house) and let the other cuts fall where they fall?

Just want some advice from some veteran pros out there.

Thank You

[tileam2000]

Also wanted to note, money may be an issue for the customer. I will strongly recommend them to cover slab prior to tile install with some kind of crack isolation membrane product. I most likely will be just covering cracks with something and not covering the whole floor because money seems to be an issue.

[jadnashua]

The distance between expansion joints depends on whether it's outside, or if there is significant sun exposure like through a series of larger windows. Outside, or where there's a lot of sun exposure inside require them closer together than an internal install without sun exposure.

You need a gap at all wall interfaces and any fixed points. So, to determine where and how many expansion joints in the field you may need, we'd need to know the room layout and measurements and window and sun exposure.

[Davy]

Andy, try to sell the membrane if you can. I have even installed the membrane free if they will buy it, it doesn't take that much time to apply. On jobs like this, it may save you from warranty work later on.

[tileam2000]

Davy, I had thought about telling them Id do the membrane for free. Its 1600 sq ft to lay down. Im doin the job by myself with no help and already giving them a great deal on the sq ft.
This particular customer is actually a friend as well so thats why Im giving them a good price.

[Elkski]

I seem to remember needing a joint closer 20' and closer with Sun exposure. I used the shluter metal joint with flexible grout joint in a near color match and it is hard to pick out now.

[tileam2000]

I am installing 1600 ft of 20" Porcelain (Daltile) for a customer. I looked at 3 samples tiles they had and already seen a size difference of almost an 1/8 inch! The problem is the home owner really wants small grout joints no larger than 1/8''. I told them that if there is an 1/8'' difference in size on some tiles and the grout joints are 1/8" than some of your grout joints will shrink up to 1/16" on both sides and you wont have any consistency in you grout lines. It will look bad and ultimately since I am doing the job and my name is on it I really dont want to install a floor that looks bad because the average person that looks at the floor will assume that the tile mechanic set the tiles uneven. They did say they are contemplating having me run the tile on a brick pattern which may hide the size diffence some, but it will still be a factor. I strongly recommended to continue shopping and a better more 'true' tile will come up, but they are getting this tile for $1.20 sq ft and money is definitely an issue.

What do you recommend I tell them?

[Lazarus]

You can tell them that it is universally recommended that the joint width of a given tile MUST be at least three times the "variation" in size from the smallest tile measured to the largest.

With 1/8" variation, grout joint should be a minimum of 3/8." At the price they paid, any smaller will appear to be a Hack Job. Ask if that's what they want.

[tilejoe]

That's the kind of tile you get for $1.20 a foot.

Speed, quality, price, pick two.

You are looking at 3/8" lines.

[tileam2000]

I understand the ratio method of opening up the grout lines to accommodate for the tile size inconsistency, but theres no way I'd ever lay 3/8" grout lines, lol. Thats ridiculous. Im definitely going to try and talk them into looking for a different tile.

[cx]

This the same 1600-foot job in Florida you posted about earlier, Andy?

[tilejoe]

Sorry, I meant 3/16" lines, you could make that happen.

3/8" are freaking canyons

[Ken]

Originally Posted by tilejoe

Sorry, I meant 3/16" lines, you could make that happen.

3/8" are freaking canyons

I think running a 3/16" joint would look horrible when the author of this thread has already said that three sample tile he's looked at vary by 1/8".. Gonna be hard to make that look nice.

[tilejoe]

Originally Posted by kurgon

I think running a 3/16" joint would look horrible when the author of this thread has already said that three sample tile he's looked at vary by 1/8".. Gonna be hard to make that look nice.

2 opinions. And neither one of us is doing the work

[ob1kanobee]

Grid the floor and make it work or use your eyes to do the best you can. They are after all million dollar instruments and for some of us they still work. If set some, say 50 sq. ft. or so and let them look at what the best you can do is. If they are happy with it then continue and have them look again at some point. They just aren't gonna line up exactly but a good grout job helps a lot. Spacers will throw you off pretty far and if the tiles are that bad they won't be much good.

I use grids in these instances so I have straight lines and fudge/work out the rest. It's like Mexican tile only on a micro level. PITA but it is what it is.