Making a small cottage with a thatched roof. Decided on the standard method of using teddy bear fur. First, I cut pieces of fur a half inch or so larger than the sanded roof all the way around. Glued the fur to the roof being careful to ensure the nap direction of the fur ran from roof peak towards the bottom edge.
Once the glue was dry I trimmed the edges by barely cutting through the fur’s backing within a quarter inch of the edge and pulling the excess away.
Using a scrubbing motion to make sure the paint got into the fur I painted it a yellowish brown.
Then jammed the comb against the nap to separate individual rows. Let it all dry.
The roof looked too yellow to me so I washed it a grayish brown, drybrushed it a light gray, and snipped away errant bits to neaten it up.
ALTERNATE: Another method is to use a terry cloth. An excellent tutorial is at http://ryan.skow.org/city/greentree/ThatchedRoof.html. I decided not to have separate rows this time. I used an old green towel, which added an extra step of spray painting the roof black after the Scenic Cement had dried. The resulting roof is much different that the previous one.