Finding the source of a roof leak can sometimes be easy. On other occasions the leak will require detective work and possibly a garden hose and an inside spotter to determine the origin of the roof leak. If you don’t feel comfortable on a roof, you will have to find an honest roof repair expert to assist you. Sometimes this can be just as hard as finding the smallest leak because some roofing company’s are just out to make money.
For your safety it is highly recommended that an experienced and qualified roofing expert should inspect your roof. Like any credible roofing contractor, Waukesha Roof Repair provides free inspections — with the exception of our emergency service.
For information purposes, here are some of the common roof leak areas:
The Field of Shingles
If you have an older roof it is possible that the roof leak is within the roof field. What this means is that the leak is somewhere within the expanse of shingles, slate, shakes, or whatever type of material your roof consists of. If your roof is asphalt, then you can often times inspect the shingle field with ease; unless of course the roof pitch is very steep. When this is the case, finding the roof leak will require other methods such as using a hook-ladder or a combination of jacks and ladders. Other materials such as slate or steel roofs may not be so easily inspected either as you can crack the roofing if you walk on it, or it is too slippery to walk on. In most cases, however, it is as simple as looking at the roof from the ground and noticing that a shingle or tab is simply missing and allowing water to migrate through and into your home.
A valley is a line where two roof planes intersect. Here in Wisconsin metal flashing in the valleys is most common. However, some roofers use rolled roofing or they will lace the shingles together to form what is referred to as a California valley. Valleys can be big problems if you do not trim the shingles correctly. When you trim a shingle for a valley you end up with a chisel point on the end of the shingle. If a second cut is not made to make this point blunt, then water can travel along the top of the shingle and find its way inside your house.
Head Wall Flashing’s
Some roofs stop at a vertical wall where there is a dormer or other structural protrusion such as a chimney. In these cases a metal flashing must be in place to direct water streaming down the wall away from the stopping point of the shingles. This flashing is often behind the siding or in front of a brick wall.
These flashings extend over the shingles at least three inches. If the wall is brick or other masonry there is an additional counter-flashing which bends and extends one into a mortar joint or a cut joint. Generally tar, caulk or roofing cement will be used in conjunction with the exposed seam where the metal flashing intersects the brick or stone and it has simply decayed or cracked. Other times the metal itself is corroded and must be replaced in its entirety.
Chimneys are the number one source of most roof leaks. Chimneys contain four different types of flashing. Each and every one must be right or you will have a roof leak at the point where the chimney enters the house. Moreover, the counter-flashing that goes into the brick or mortar joint must be right. A hairline crack above the flashing can allow vast amounts of water to run behind the flashing’s and leak into your house.
Wall Step Flashing
Some roof leaks happen at step flashings. Step-flashings are used where a roof climbs alongside a vertical wall. As each row of shingles is laid, a step flashing is installed over the shingle next to the wall. Part of the flashing turns up on the wall and the other portion gets covered by the next row of shinglesand often times cannot be seen. Some times these metal flashing corrode and need replacement, while other times they simply were installed incorrectly or simply are missing.
Plumbing Vent Flashing’s
Newer vent flashings that seal PVC vent tubes incorporate a rubber seal with an aluminum flashing. The rubber can fail in as little as 10 to 15 years.
You’ll recognize this flashing because it dives up and under the shingles that extend up your roof from the middle of the plumbing vent. The bottom half of the flashing will be exposed and actually covers the shingles below the pipe.
Furnace or B-Vent Flashing
These flashings are basically identical to plumbing vent flashings. However, they sometimes have a metal storm collar. These simply fit tightly around the vertical pipe that exits the roof. If the storm collar becomes loose it can cause leaks. Otherwise, and on rare occasion the metal flashing itself will corrode and fail.
Ice Dam Leak
Ice dam leaks plague us Wisconsinites here in the snow belt. These leaks can happen even if everything on your roof is just fine!
Ice dams block the natural flow of water down a roof. The water begins to back up under flashings, shingles, tar paper, etc. Once water begins to flow into the house, it can drip for days. The only means of preventing this problem is to install an ice and water shield membrane under the roofing.
The membrane itself won’t stop the ice, but it will stop water leaks if installed properly.
Wind Blown Rain Leak
Wind driven rain can also be a major problem. Once again, you could actually have a good roof and wind will drive water up and under your roofing materials or flashings. The only lines of defense are tar paper and the ice and water shield membrane.
Non-Roof Leak !
Sometimes you think you have a roof leak when in fact the roof is fine. Attic condensation is a prime example. High humidity can cause condensation and “rain” to fall in your attic. It can also make the underside of the roof sheathing look wet. In these cases you may think you have a roof leak, but instead its just condensation.