12 x 18 Herring Bone Expansion Joints

[bctile601]

Have a larger floor project to start using a 12 x 18 over crack isolation membrane laid in herring bone pattern on diagonal. On plywood with I-Joists. Floor measures out a bit over 1800sf. There are basically 2 larger rooms, one completely open, the other 1/2 has a stairwell amd several rooms. It seems to mee that cutting a silicone joint across the doorways will not be enough. Cutting across this diagonal layout is certainly not in the minds of the client.

Looking for best way to install joints so the work is done correctly, and the least noticeable for the client.

Also looking for ways of explaing the cut joints.

[gueuzeman]

TCNA handbook is always a good start. Then point out that it says that an engineer should be spec'ing the exp. joints, and you think they should pay for that.

Last resort I always invite them to go on a walk down all the tiled hallways of a local shopping mall, plenty of patterns, expansion joints, and broken tile to see usually.


.

[eurob]

It seems that the only way of doing this -- not cutting across an expansion joint -- is to locate the areas where the expansion joints will be and use a flexible joint ( soft joint ) on both sides of the row of tiles ( same location of the expansion joint ).

You can also consider This method .

[Dave Gobis]

Stair-step joints are better than nothing. We have been having this argument a number of years. Over wood is even more problematic given the joist bay deflection. Hope the floor is good and stiff.

• saw-tooth joints affect the
performance of sealant and caulking
materials and are not recommended
unless used with a crack isolation
membrane.
• refer to sealant section in ANSI tile
installation specification.

[bctile601]

Enjoyed a quick conversation with the client and we have selected a few spots ( 6 ) in the 1800sf to place saw cut joints and fill with silicone. All the tile work is over crack membrane, floor isn't ' stiff ' but ain't sappy either.

[cx]

Brian, I don't know how big that tile installation might be, but I don't see that skinny little cut buying you much protection. If it's gotta be there, I'd at least make it wide enough to do some good.

[bctile601]

I understand that the joints should not be less than 1/8". These are 1/8", the grout joints in the tile are 3/16".

[cx]

Actually, I believe the industry standard calls for a minimum of 1/4" for that joint, Brian.

And, again, I'd wanna know the size of the entire installation and other factors to determine if even that was enough.

[bctile601]

it reads ' preffered not less than 1/4", but never less than 1/8" '

I might be able to cut the tile in-place to widen the joint, but this will introduce great risk of ruining the installation.

[cx]

Might wanna read that again, Brian.

The line you quote is for mosaic tile and glazed wall tiles. The requirement for pavers is "same as grout joint, but not less than 1/4."

You really aughta do something with that if you can. Your customer is gonna be sufficiently unhappy with having that cut joint without having a cut joint and still having a movement accommodation problem down the line, eh?

[bctile601]

ha, right again eh CX ? !!

will hafta risk that cut.

[John Bridge]

Something with a water attachment, Brian.

[bctile601]

Yes, I have an Alpha, just need to change out the turbo blade that's on it. May have to re-cut the edge tiles.

[John Bridge]

Might be a three-person job. Somebody to catch the spray and somebody to hold the other end of a long straight-edge that the saw can ride against.

[cx]

I'm thinking it you don't have a little hand-held wet saw like the Felker FHS-4 it might be a really good time to get you one. Or is that what you're calling "an Alpha"?

Maybe you could save one of JB's three men by attaching the straight-edge to the subfloor in the grout joints?