A galvanized steel roof has a life expectancy of an impressive fifty years under normal conditions. However, there are sometimes unforeseen conditions that can cause damage to the roof requiring it to be repaired before water leakage causes further damage. Even if the leak may be small, a leaking roof can quickly cause major damage to the interior or even the structure of the building itself. There are various methods of repairing a leak in a galvanized steel roof, and these repairs need to be carried out in stages. Some repairs, done with the right materials and to a professional standard, can last the entire life of the roof. Only work on the roof when the weather is dry and calm. The surface of the roof also needs to be completely dry.
Step 1 – Measure the Repair Area
Before you start, accurately measure the length and width of the hole, adding a couple of inches extra to both of these dimensions. This will determine how much materials you need to finish the job. Get the galvanized metal sheet that you will be using to repair the damage. Mark the measurements on the underside of the metal using a permanent marker pen.
Step 2 – Cut the Metal
Cut the metal using specialized metal snips. Set the scribe to a half of an inch, and run it along the edges of the cut piece of steel, snipping each corner of the patch at a 45 degree angle. Use the metal snips for this as well. Be sure that the angled cuts cross through the intersection of the half-inch scribe lines. Fold the sides of the metal patch using a sheet metal seamer, and use the scribe lines as your reference lines to mark the bends. All of the folds should bend towards the surface of the patch.
Step 3 – Clean the Metal Patch and Apply the Flux
Before you can apply it to the roof, the metal patch should be cleaned and smoothed using 120 grit sandpaper. The edges of the hole in the roof should also be cleaned in the same manner before applying flux to the edge of it and the edges of the patch. Use an acid brush to apply the flux thoroughly.
Step 4 – Place the Metal Patch
Place the patch over the repair area and place a weight upon it to keep it help firmly in place. With a heated soldering iron, rub lead-free solver around the edge of the metal patch, allowing it to flow under and set to fix the patch in place over the repair area. The solder should be left to cool and thoroughly harden before you should remove the weight. When it is dry, remove the weight and refinish the surface of the repaired area in the same manner as the rest of the roof.
( Source : http://www.doityourself.com/stry/how-to-repair-a-galvanized-steel-roof )
