A roof that looses its waterproof integrity can cause a great deal of problems for the building. The area of the roof around the leak begins to rot as well as the area under the leak inside the structure. One of the key linchpins of the waterproof system of any roof is the flashing. Follow these steps to replace roof flashing.
Remove the surrounding shingles. In order to replace roof flashing you need to remove the shingles that are laid on top of the old flashing. Be very careful when removing the shingles. If you pull the nails from the shingles cautiously you can reuse the shingles after you replace the roof flashing.
Loosen the siding. If the flashing is running up along the side of a wall, you must loosen the bottom of the siding so you can remove the flashing from behind the siding and slide the new piece underneath where the original piece was.
Cut a new piece of flashing to replace the old one. Use the metal snips to cut a piece of new flashing. If you make a mistake, make sure you error on the side of cutting the piece too long instead of too short. It is much better to cut a little off to make it fit than sticking another piece on the end.
Crimp the new piece of flashing. Use a metal break to bend the flashing down the middle at a 90 degree angle. This is not necessary if you are going to use the flashing to replace roof flashing along a valley in the roof.
Lay the flashing where you want it and nail it down. Drive the nails as far towards the edges as possible where they are covered by the shingles or siding. Flashing with a nail in the middle of it cannot do you much good.
Replace the shingles and siding. Nail the shingles and siding that you loosened back into place on top of the new piece of flashing. Use the roof cement along the outside edges of the shingles so water can not flow back from the flashing underneath of the shingles.