Roofing felt is a heavy black paper that is filled with asphalt. It comes in rolls and is a layer of weather protection when installed as an underlayment over roof decking. The most common size for roofing is 36 inches wide and is called a 6.8kg. paper. Some rolls come pre-marked to help you keep the strips straight on the roof. Drip edge along the eaves, valley liner and flashing should all be installed before the roofing felt. Drip edge along the rakes should be installed after.
Step One
What is Roofing Felt? - Roofing felt is a heavy black paper that is filled with asphalt. It comes in rolls and is a layer of weather protection when installed as an underlayment over roof decking. The most common size for roofing is 36 inches wide and is called a 6.8kg. paper. Some rolls come pre-marked to help you keep the strips straight on the roof. Drip edge along the eaves, valley liner and flashing should all be installed before the roofing felt. Drip edge along the rakes should be installed after.
Step Two
Preparing the Decking - Before you install roofing felt, you must clean the decking well. It should be free of moisture and debris. If any of the decking has moisture or other damage it should be replaced at this time. Go over the entire deck to check for nails. Sometimes when old roofing material is removed, the nails do not come out with the material. Run a flat head shovel along the decking and it will stop if it hits a nail. Remove the nail and make sure there are no wood splinters sticking up. Once the decking is ready, snap a chalk line 33 5/8 inches above the eave line. This will allow for a 3/8 inch overhang of the first strip of roofing felt. Snap the rest of the lines, moving up the roof every 34 inches.
Step Three
Install the Roofing Felt - Begin the installation at the eave edge and roll from rake to rake. Tack the paper down around the centre to keep it from blowing or falling off the roof. Cut the paper flush at the rake with a utility knife and adjust it to your chalk line. Make sure you have your 3/8 inch overhang. Once you have it adjusted and lying smooth, nail with roofing nails or staple in place every three or four inches on the lower half of the paper. Repeat the process, moving up the roof until you reach the ridge. Where the paper meets end to end, overlap it by four inches. Overlap by six inches at valleys, ridges and hips. If you need to fit the paper around a vent pipe, slit the paper and fit it over the pipe.