Green roof waterproofing

The thought ocurred to me that there might be a green way of waterproofing a (wooden) roof using some sort of tree resin, or a mixture of different resins or another compound. I'm posting this to encourage brainstorming on this as I was surprised to not being able to find anything concrete on this through google.

I suppose tar could be called natural, but hardly green because of all the carcinogens in it. But resins seem to me to be a viable candidate to start with. As I understand pine resin, if used, would have to be mixed with something to stop it from setting completely in cold weather and cracking? What could accomplish this?

What have you guys used? How did you fare?

(WHOA! Why does my name have "Hatfield" in it allofasudden?? What is Hatfield anyway?)

Paddy, the new forum software requires a last name. Hatfield and McCoy have been used until you fix your name.

Were the original wood shingles coated with anything? I always thought it was the layering of the shingles and steepness of the roof
that kept the water out of the house. Now I am wondering...

Well that's true but in time untreated wood would let water through.

Make a paste from linseed and wood ash, paint on and let dry. It acts as a insecticide and petrifying agent. You'll not live to see the day it rots.

Ding Fod wrote:Make a paste from linseed and wood ash, paint on and let dry. It acts as a insecticide and petrifying agent. You'll not live to see the day it rots.

I like that idea much myself, would you use ashes of hardwood or no matter what kind?

In the old days of wooden ships, they used to use a tar pitch made from trees to waterproof their ships. That's why sailors used to be called "tars".

Ding Fod wrote:Make a paste from linseed and wood ash, paint on and let dry. It acts as a insecticide and petrifying agent. You'll not live to see the day it rots.

Would this work for treating posts in the ground in a WOFATI?

aman

I don't know how long it would last but indeed, pine tar was once the only way to waterproof a ship. As I understand it you had to continually maintain the ship in order to keep it waterproof.

http://www.youtube.com/watch?v=zv0JMKbFsrQ

The by-product is char. Char coal is a mixture of natural tree char, and mineral bed coal. Hence charcoal.

Anyway, you might find it useful, although getting enough to make this meaningful would be tough I suspect.