I am doing a rough job putting a little roof on an outside toilet.

It's only 4 feet long and I'm using those concrete tiles which are

in the shape of the old sheets of corrugated(crimped) metal that I

used to see in Europe a long time ago.

Anyway,I want to seal where the long side of the tiles are flush with a concrete

wall.

I was going to use silicone but the gaps were too big in places so I put

wall putty on first and it looks O.K.

My question is ...what do I do next...........

1-should I just leave it at that....is wall putty water proof...will it make a seal.or

2-put a layer of silicone on top of the putty.

Expanding foam? that's what I used when I found out the "builders hadn't left enough of a overhang!

Typically on a 'Roof tile to Headwall' install, you would have a run of sheetmetal flashing that lays on top of the tiles and extends up the wall. This should be sealed on the top of the sheetmetal where it meet the wall with roof cement or another small piece of sheetmetal to protect against water pushing into the joint. The lower side over the roofing tiles is typically left open to allow any water that may get under the flashing to have an easy path to drain out.

I would recommend doing a search for 'roof flashing' and the checkout the images on the various methods used to do what you want to accomplish.

Cheers!

Thai style is to put a wedge of concrete at the join. That's very rough.

Google 'Flashband tape' for ideas.

Is roof cement available in Thailand.