Hello all!

I've been resorting to TOH ever since I bought my house. Most of the time the solutions suit the work directly, but this time I really don't know what to do, and since the task is quite specific, I decided to ask here.

I couldn't attach the picture to this post (not a valid image file?!), so here's a link: https://lh3.googleusercontent.com/-n...ketch_roof.png

To put that picture into words:

- my shed was built using concrete posts (6x) between which concrete slabs where inserted. Then a 2cm diametre bolt was placed at the top of those posts, probably using a bore in the post itself. Overall, the shed is a rectangle with posts at each corner, plus two in the middle of the long sides.

- a thick wood beam was placed along the top of each long side; it had to be bored as well to let the bolts through. The bolts where then bent onto the wood... It was on top of these beams that simple corrugated boards where fastened to make the roof. The angle was achieved by having the concrete posts on one long side be taller than the others.

Now, both the corrugated plates and the wood beams need to be replaced (they rotted where the bolts securing the plate penetrate). I could try to bend the large bolts back into place and replicate the current arrangement. On the other hand, I'm wary that the wood is also rotten and going to rot further at the concrete/wood interface, because the concrete seems to get wet all the time. I also want to raise the roof by about 30cm, and that requires a good frame on top of that concrete..

How would you go about connecting a wood frame to that concrete? Also, what would be a sensible scheme to prepare a wood frame on the concrete that would make building the higher roof on top of it easier (ie, since the concrete sides are not level, placing joists is harder..)?