FIRSTLY RIP OFF OLD FELT AND REMOVE ALL NAILS. THEN CHECK THAT THE BOARDS ARE SOUND IF THERE ARE THEN REPLACE THEM. THEN YOU NEED TO PURCHASE SOME MINERAL FELT IT COMES IN ROLLS ABOUT 1200MM WIDE. CUT OFF A LENGTH ABOUT 150MM LONGER THAN THE ROOF ITS SELF AND PLACE ON THE EAVES (BOTTOM OF ROOF) AND OVERHANGING EACH IN BY 75MM SO YOU CAN TUCK IT UNDER THEN USING SOME 15MM GALVANISE CLOUT NAILS NAIL THE TOP OF THE FELT TO THE ROOF TIMBERS,MAKE SURE THE FELT IS PARRALLEL TO THE EDGE OF THE ROOF. REPEAT THIS ON THE OTHER SIDE AND WORK YOUR WAY UP THE ROOF MAKING SURE THAT YOU OVER LAP EACH ROW BY ABOUT 150MM MAKE SURE THE TOP PIECE OF FELT COVERS THE RIDGE AND THE EDGE OF THE FELT ON BOTH SIDES THEN NAIL THE BOTTOM OF THIS PIECE AND IT WILL BE WATERTIGHT EACH NAIL SHOULD BE ABOUT 100MM APART ONCE YOU HAVE COVERED THE WHOLE ROOF NAIL THE EXCESS AT THE EAVES UNDER THE ROOF. HOPE THIS HELPS
GRAHAM LAMB, August 2008
