If your roof is leaking, don't despair. You can find and fix a roof leak yourself to protect your home until you can get professional help.
How to Find and Fix a Roof Leak
Finding a roof leak can be tricky, but a doing a temporary fix yourself can save your home.
Head For the Attic
To find your the source of your leaking roof, make for its source: the attic. Take a flashlight and go up during the day, either while it's raining or shortly after a rainstorm so the moist spots will still be visible. Step carefully from joist to joist rather than on the space between joists--you don't want to fall through into the room below you. Look for spots that may be darker than the surrounding area--a telltale sign of moisture--or for spots of mold that will show you where the leak is coming through. Once you find a sign of a leak, use your flashlight to follow the dark spot or mold stain upward along the roof. Remember, water leaks downward, so the actual source of the leak may be higher than the place where you see evidence of it. Once you find a likely looking spot, try turning off your flashlight and looking for a spot where daylight shines through. The leak might be small enough that you can't see daylight or the water might be seeping between some overlapping shingles, so a lack of daylight isn't a sign that there is no leak--but if you do see the light, you know that you've found the spot that needs roof leak repair. If your roof has insulation, keep in mind that you can't find the source of your leaking roof just by looking at discolored spots on the insulation; there may be a lot more water damage on the side of the insulation that you can't see, and the only way to find the source of the leak is to remove the insulation and look directly at the wood.
Simulate a Rainstorm
If you're in the middle of a dry spell but want some roof repair before the next rainstorm comes in, you and another person can simulate a rainstorm to find the source of your leaking roof. While you're in the attic with your flashlight, send a friend up to the roof with a garden hose. Have your friend run the hose over the roof one section at a time while you look for leaks with your flashlight. This has the added bonus of giving you a controlled setting to look for leaks; if it's actually raining, there will be rain all over the roof, making it harder to pinpoint the source of the leak. With a friend helping, however, you can know exactly what section of your roof is damaged so you can find and fix a roof leak more easily.
Emergency Roof Repair
Once you've found the source of the leak, you can jury-rig a quick roof leak repair with nothing more complicated than 6-mm polyethylene sheeting and a few two-by-fours. Measure the leaking section of the roof, then cut out enough sheeting to cover it, giving yourself about four extra feet for good measure. Staple one end to a two-by-four that's as long as the plastic is wide, then nail another two-by-four along the top to make a plastic "sandwich." If you're trying to do a flat roof repair, you can simply make another two-by-four "sandwich" on the other end to keep it from blowing away and place it on the leak. If your roof is sloped, you can drape the plastic over the peak of the roof, then make another "sandwich" at the bottom. Some experts recommend using roofing nails to secure the plastic instead. This is a more secure fix, but it can cause further damage to the shingles that you nail, so think about how much extra damage you're willing to cause.
Covering a Small Hole
If a small hole under the shingle is the source of your roof leak, you can fix it by picking up a 12 x 12 piece of metal flashing. Simply pry up the shingle and slide the metal flashing in underneath it to cover the hole. You may need to pry up some of the roofing around the shingle to fix a roof leak.
Repairing a Shingle
A curled, cracked or missing shingle could be the reason you need sloped or flat roof repair. If your shingle is curling, simply flatten it out and apply roofing cement to secure it in place. (This is actually a best-case scenario for a leaking roof, since cementing a curling shingle can be a permanent fix as long as it isn't curling because it's reached the end of its lifespan.) If a cracked or missing shingle is the problem, you can make a temporary replacement shingle in the same way that you would use to cover a small hole. Simply trim a piece of metal to the right size and shape, then slide it into place and secure it with roofing nails.
Repairing in Wet Weather
If you're in the middle of a rainy stretch of weather and you can't get the roofing cement to dry before it washes away, try using black tar as a temporary patch. Black tar will stick even in wet weather, so you can paint it over small cracks and gaps to create a makeshift patch until professional help arrives to fix a roof leak.