Removing the Old Roof
So, when you have been thinking about replacing your roof and gone back and forth for a while, finally deciding to go for it, then it is time to figure out what to do with the old roof. Sometimes you can lay your new roof on top of the old roof and sometimes you have to remove the old roof first. This is worth looking into before starting work. So, let us say you have looked into this and have come to the conclusion that the old roof have to go, it is best to begin tearing it up at the ridge of the roof. I like to use a short-handle garden spade with a square bottom as it is great for getting underneath the roof shingles, lifting it up and then simply removing it. Just take care not to damage the existing flashing as it can often be used as a pattern for the new flashing – even if it is a bit damaged.
Once you have removed the old roof shingles, start by pulling out any old nails that you come across and repair any damaged sheathing that you see. Broken seals along the flashing can be repaired by removing the old caulking and applying a new layer. You can patch rusty spots and small pinholes with roofing cement and use a small cut from any new flashing material you might have purchased. Make sure that the cut out bit you are using is covering the hole by about 2 inches on all sides. Prepare it by using a wire brush, or possibly very course sandpaper, around the damaged part of the flashing, clean it with a damp cloth and daub some plastic cement on the damage, pressing the cut-out patch into the cement with a firm hand. Keep it in place for at least five minutes and then cover it with a second coating of cement. I think it goes without saying but if the sheathing is too badly damaged or the area of damage is very large, you will have to replace the flashing. If you have to replace corroded metal or repair broken seals beneath the flashing, you will have to remove the shingles closest to it in order to get enough room to work with.
If you come across resin pockets or knots, try to use a putty knife or even a normal knife to remove it. Cover the area, cracks and all, with galvanised metal squares – the most commonly used one is the 26-gauge one. Remember to clean the knife used with solvent, once it is done.