Quality roof installation is key to long roof life
BY RODNEY PHILLIPS A roof will only do its job if designed and constructed to really keep the water out. Overall design, structural integrity, flashing detail, underlayment and correct shingle installation are vital to optimum performance. You might have requested "30-year" shingles, but they are only as good as their installation allows. You can't do much to correct design flaws once you own the home, so be forewarned about overly creative rooflines. Watch out for dead valleys where gable meets gable, concentrating water and trapping leaves. Be cautious of designs that transfer the rain load to a restricted area or introduce so many intersecting roof angles that water flow and valley integrity become likely problems. Extreme roof slopes are also tricky. Too steep and repair becomes a nightmare; too shallow and typical shingle installation won't be possible. Whatever the design, a roof must be built with quality material and careful labor. The framing members should follow all code requirements to provide a sound and stable platform for the decking. Properly seasoned material assembled with the correct fasteners is all it takes, but unless you know the ins and outs of rough carpentry, get your home inspector to give the roof framing a once-over. The decking is key. I like plywood on any horizontal surface, a minimum of 1/2 inch, but thicker is better. Properly installed, the decking presents a smooth, gap-free surface to support the actual roofing material and take the fasteners required to attach flashing, roofing felt and shingles. Don't forget the flashing. Flashing covers the joints at sidewalls, at chimneys, in valleys, at roof penetrations and along the eaves (the horizontal edges of the roof) and rakes (the angled edges of gable ends). Get your roofer to show you the specifications for each flashing detail on your roof and explain how his procedures will meet code requirements. A critical part of roof flashing -- drip edge -- is often neglected, although it's called for in the code. This metal flashing covers the gap between roof decking and the facia board nailed to the rafter ends along the eaves and rakes. When gutters are installed, it helps keep water from backing up into the eaves and also blocks critters like squirrels and roof rats from easy entry. Roofing felt, the black "tar paper" installed as a base for the shingles, is the first line of defense against leaks. Get an abstract of the NRCA (National Roofing Contractor's Association) manual, or talk to your local roofing supply house for a detailed look at how felt should be installed. Done properly, it will look like it could keep the rain out on its own and show a neat, craftsman-like appearance. The shingles also need to go on immediately. If the felt has been exposed to weather, it needs to be replaced before the final roofing material is applied. Now about those shingles. Despite all the brands and styles, one thing is common to all: Put them up wrong and their guarantee is void. How is it then that they are so often installed incorrectly? Sometimes it's skip nailing -- not using the correct number of nails; sometimes placement -- nailing in the tar strip; or, worse, nailing through an exposed shingle tab. Over-driving the nail damages the attached shingle and under-driving lets the head pop through the shingle tab above. The roof will eventually leak either way. Problem is, these flaws will be hidden unless the installer is so sloppy the whole roof looks bad enough to call everything into question. What if you just need a repair? All of the above applies or your repair is just a patch. It might hold for a while, but most patches lead to additional damage. A cautious roofer will remove all the roofing material in the plane of the repair. Sounds like extra cost -- and it is -- but the result will be good for all. If a contractor, however, proposes a repair without water-testing your roof to locate the leak, direct him or her to the exit portion of your driveway. Nobody cares about your home more than you do. The quality of your roof is directly proportional to the time you are on site. Be nice, but be there. David "Rodney" Phillips is co-host of the "Bob and RodMan Home Show," a home remodeling show that airs on WQXI AM 790, 7-10 a.m. on Saturdays.
| 
