If you have had some step flashing on your home for a while, you may find that you need to remove it and replace it with some new flashing. Over time, step flashing can develop corrosion, or the parts of the flashing could be broken or damaged. This could allow water to come into your home, so it is vital to repair this problem as quickly as possible. Replacing step flashing like this is not a difficult task, and you should be able to finish it in a few hours.
Step 1 - Remove the Old Step Flashing
Take off the old shingles and place them to one side. You should then be able to see the exposed step flashing so you can evaluate how badly damaged it is. Sometimes it is better simply to lay the new flashing directly over the old, but if you are not too keen on doing this, then you should remove the flashing by chipping off the caulk, and then pulling off the roofing nails with the claw side of your hammer. Once this has been done, use a crow bay to pry up the old step flashing.
Step 2 - Adding New Step Flashing
Begin by measuring the length of roof you need to cover. This will allow you to determine how much step flashing you need to purchase. If you by flat flashing, you will need to bend it to form the 90 degree angle required. Find the first piece of flashing and install this into the flashing siding. Push it under the exposed shingle, and then caulk the edges to hold it firmly in place. You should then add more caulk to the edges of the flashing in order to secure it to the roof.
Step 3 - Adding More Step Flashing
Once you have added this piece, you can then continue to add the rest to your roof. Use nails to hold the step flashing in place along the vertical connections. Cover this hole using some caulk, and place the next layer of flashing well over the hole. This should stop water from penetrating the hole. Repeat this process all along the roof, taking care that you follow a good line, and don't leave any gaps along which water could get into the roof. Use a lot of caulk to provide a good seal when laying the step flashing.
Step 4 - Completing the Job
When you have finished adding the step flashing, you can then put the shingles back into position. Make sure that it overlaps with the edge of the flashing. Lay from the furthest shingle in towards the middle of the step flashing, so that the water is pushed towards the valley. A single roof nail should secure all of your shingles, and you should also take the opportunity to discard any that look damaged, or which are unsuitable for re-use.