For this I use: 2 pieces of c/board cut to fit either side of the roof with a cutout for the chimney.
2 pieces of c/board cut to match the angle of the walls.
Matchsticks for support.
Scouring pads for the tharch.(use the cheap one's and splt them)
I then stick the 2 roof halves together with masking tape - glue in the angled pieces and supports.
Once everthing has dried I paint the roof and then start lying on the Thatch.
I cut strips of equaal width and one slightly wider.Then the strips are glued on one overlapping the other.Once both sides are done I use the wider strip to form the roof cap.