Joe, you can overlap as logic would indicate, but you don;t have to.

As long as you have the 50mm or 2" overlap at the seams, no worries!

Capillary action is not a factor.

I thought I read a few years ago that the Schluter boys built a Kerdi-lined container and filled it with water. I forget how long they let it sit. They later tore it apart and water penetration into the seams was essentially negligible.

Kerdi is also hydrophobic. You can take a piece of it, roll it into a tight cone so it looks like an ice cream cone, add water, and no water will leak out the bottom.

I seldom have this much faith in a product, but I think Kerdi is a great product.

It's so good I even used it in my Mom's bathroom! And if it's good enough for Mommy...

Mongo

I really questioned this myself on how Schluter video showed it.

I knew it didn't matter but I thought putting in the corner strip on side and floor last would be preferred, so water can
better run over the Kerdi, especially on the floor ..this is what I did.

Konrad

I thought I read a few years ago that the Schluter boys built a Kerdi-lined container and filled it with water. I forget how long they let it sit. They later tore it apart and water penetration into the seams was essentially negligible.

It was 3' deep, and they let it sit for 24 hours, and it only penetrated 3/4"

Thanks for the replies. It's nice that it can be installed in any sequence, whatever is convenient for the situation. For piece of mind, I'll probably go bottom up anyway to reduce the impact of first time user snafus. Vertical installation as Mongo did in his Kerdi 101 lesson also seems like a good idea.