The idea is to get more space under the existing porch for sitting in the rainy season plus cover for motorbike, etc.

To one side some 3 meters. Here the soil is slopping down some 30 cm. To avoid a sagging foundation I thought of using metal planks on short pillars. Cheaper than a concret sturctur? What would you use, what planks, wood is slippery when wet.

Any suggestions how to protect somewhat, not 100% against driffting rain?

We extended our porch also. Some 3 meters or so. Here's a thread where I posted some pics:

http://www.thaivisa.com/forum/topic/257672-finished-house-picture-views-and-gardens-welcome/page__view__findpost__p__3796054

Tile is also slippery when wet. And when it's windy, the rain comes in some meter and 1/2 or so. But that doesn't happen all the time. It sure is nice when it is really sunny out or when it's rainy.

Tiles! Much simpler and cheaper than wood and , of course you are right, anything is slippery in rain. Probably filling the slope is not such a big deal, as I thought. KISS= keep it simple!