How To Install Roof Felt
Want to learn to install roof felt? Installing the felt on steep roofs is a slow, difficult and tedious job. Be careful!
I use 15lb. felt (tar paper). If you expect an extended time to get the roof on, you should use 30lb. felt, as it will resist the weather better and longer. Of course, it costs twice as much, because it covers half the area.
STEP 1: To install roof felt, starting at one end on the bottom edge, lay the felt in place and nail the bottom corner once. The felt should not hang over the fascia edge or the end, but just cover the decking.
STEP 2: Roll the felt out ten or twelve feet and straighten it up so that it is running true with the roof edge.
STEP 3: Use 1” plasticap nails to fasten the felt. Place three nails on every rafter. Do not nail the top edge.
STEP 4: Continue across the house and cut the roll off. Nail the first run complete and cut off any excess on each end, as this will catch wind and tear the felt up.
STEP 5: Place the felt for the next run, overlapping to the first line on the previous felt, (this should be two or three inches).
STEP 6: Tack the bottom corner, roll the felt out ten or twelve feet and straighten it up so that it is running true with the previous run’s line.
STEP 7: Maintain the line of fasteners you began, placing three nails on every rafter. The nail along the bottom will nail the top of the previous run as well. Again, do not nail the top edge.
STEP 8: Place the felt on the dormer roofs, lapping it onto the house roof a foot or so.
STEP 9: Run felt on the house on top of the dormer felt.
STEP 10: Continue running the felt on the house side until you lap over the top.
STEP 11: Lap the felt over the top ridge and nail it down on both sides, even if you are using ridge vents. The felt will be cut out later, if you are.
Now you have learned the proper way to install roof felt.