ripped out the underlayment and the subfloor is 5/8' TG. I plan on putting down 1/2" underlayment, ditra and then tiling. Question about estimating the amount of tiles needed though. The kitchen is 240sq/ft (approx) and I plan on doing a pattern much like what Harry did here:
www.ontariotile.com/photos/harryspics/heatedfloors/easyheat10.jpg

the tiles I'll be using are 18" and 6.5" porcelain as shown here:

http://www.kulkarnicorp.com/images/tiles/pattern.jpg

Is there an easy way to estimate how many large/small tiles I'll need?

thanks!

Davey,

That is known as the Hopscotch pattern. You will need an equal number of pieces in each size. Normally the small tiles are one quarter the size of the large tile. In that case it would be 80% large and 20% small tile by the sq. ft.

Since yours size ratio is not 1:4 as in (12x12 and 6x6, you'll have to find the ration between the 2 sizes. My brain is too tired right now to do it for you. But it's easy.

Jaz

Dave, maybe my brain isn't working correctly this early in the AM, but is that pattern going to work out correctly? I would think that the smaller tile would have to be 1/2 the width or 1/3 the width of the larger tile to keep the pattern consistent. Incidently, your ratio is
7.7 to 1.

Maybe the pattern won't work. I hadn't thought of it that way and without enough tiles here to test the pattern I couldn't see it. By what Jaz is saying the smaller tiles would have to be 4.5" not the 6.5" that I have. Back to the drawing board...

If you do the same pattern as your photo it will work. The two tile sizes don't matter.
Becuase your pattern is one large tile and one small just add the square footage of the two pcs. (18x18 and 6-1/2x 6-1/2)for a total of 2.55 sq ft Divide that into 240 sq ft which gives you about 94pcs of each size.
Depending on how chopped up the room is, you will need to add a min waste factor of 15% to that number.

Randall is right,the tile sizes don't matter.A few times I've used 20" and 13" in the "hopscotch" laying pattern.Only once a third tile size is added to the composition are the sizes important.Then the tiles will dictate the width of the grout joint.

I like the multisize tile laying patterns as they don't have a continuous grout line or that grid effect.In the future,I think the trend will be these types of laying patterns...in residential design anyway.

RC, I had to sit and stare at your drawing for five minutes to figure out how that would work, but I guess you are correct. Apparently I wasn't tilting my head in the right direction when I first looked at it.

thanks for all the replies. I'll get my head around this and then start tiling, reporting back with pics of course. I guess the one drawback is the tiles meeting the walls will change in size as I go along, not a big deal though.

David

Hey Ron,

How do you deal with your edges? From some rough drawings I've done it looks like I may end up with edge pieces being on 1/8" thickness in order to complete the pattern.

Dave, this would be a non linear pattern so no grout lines will be aligned. So your probably only going to have a few small pcs.

Depending on how precise you want to be, you might want to just have an extra wide grout space near the wall in those spots.

Unfortunately it's one of the drawbacks to this kind of pattern.