Bob flashed back to the installation of the new roof. First the crew removed the old layers of roofing material from the barn. Next they added a layer of Louisiana Pacific oriented strand board (OSB) over the original sheathing. It's manufactured with thin wafers of wood, resins and wax compressed under intense heat. When used as roof sheathing it's extremely resistant to moisture damage. Then they stapled down a layer of felt paper and marked with chalk lines to lay out the courses of asphalt shingles. Since these are double layer shingles, they're fastened along the pre-marked white line to assure that both layers are attached to the roof. Frames for the Velux VSE skylights were installed. These vented skylights will be operated with a hand-held remote. Copper step flashing is added to the side of the skylights and the asphalt roof shingles are fastened up to it.

Bob and Jack Viera demonstrate installation of 3-tab asphalt roof shingles. An ice and water barrier is added and secured with aluminum nails.

Kevin Benjer in on hand to demonstrate the correct way to apply asphalt roofing shingles and a ridge vent. Chaulk lines are drawn to ensure proper alignment and then each course of shingles are added. The ridge vent is installed last and help provide ventilation to the attic.

Ryley and Dominic demonstrate installation of architectural grade dimensional asphalt shingles on the Habitat for Humanity Blitz Build house in Yonkers, New York.

Bob and roofer Paul Morris start by cutting a rough opening in the roof and laying a weather shield. The skylight is mounted into place and the flashing is applied. Bob then assists in laying the new asphalt-shingles.

When roofing your house, consider using a metal roof. Available in a variety of colors and styles, metal roofing is made of recycled materials and can be recycled itself, saving space in landfills. Considered a lifetime roof, a metal roof lasts four to five times longer than asphalt. And it performs better in fire, snow loads, hail, and high winds.

Here s another great tip from BobVila.com. When photovoltaics or the conversion of solar energy to electric power came on the scene 30 years ago, it was so inefficient that few thought it could ever power American homes. But the technology has come a long way, and demand for PV systems in the U.S. is now growing at almost 25 percent per year. In sunny California, brownouts and energy crises have pushed the state to set an ambitious goal of putting photovoltaic systems on a million roofs by 2016. The cost of installation can be daunting for homeowners, but government incentives make them much more enticing. The federal government rebates $2,000 per system. In California, the state not only gives a property tax reduction for the cost of the system, it also rebates $2.50 for every system watt. So, a 4-kilowatt system that costs $36,000 only winds up costing the homeowner $24,000. In Florida, homeowners can get $4 per system watt, so the same system costs only $18,000. Add to that the value of the electricity generated by the system which, depending on your area, can be between $250 and $750 per year and photovoltaics start to make a lot more sense. As roof-mounted panels or even integrated into asphalt roof shingles, photovoltaic cells contain silicon wafers which react to sunlight by releasing free electrons. These electrons create direct electric current, or D/C power. The system s inverter switches the D/C to the alternating current, or A/C, that powers our homes. Household photovoltaic systems have become simpler and better adapted to mainstream use now that grid-tied net metering is easier and no battery backup is needed. Any electricity the system generates that s not used in the home gets sold directly back to the power company. In sunny areas, the larger 4-kilowatt systems available today can generate half or more of what the average household consumes. Even where it s not so sunny, photovoltaic systems have become so viable that many forward-thinking developers are pairing them with geothermal heat systems to market the new non-polluting, low-energy home. Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com

Bob Fulmer from Harraseeket Restoration, Inc. joins Bob on the roof of the breezeway to install a double-lock standing seam copper roof. Before installing the copper, a plywood deck is applied, followed by a layer of bituthene for moisture resistance and then a resin paper slip sheet. The resin paper helps absorb the condensation generated on the back side of the copper panels by temperature changes. Additionally it insulates the copper from touching asphalt-based underlayment or bituthene on which standing water creates a diluted form of sulphuric acid which will degrade the copper. The copper panels are brake-formed at the shop and brought on site ready to install. The panels are joined in a double-lock standing seam in a two-step process. First the male edge is locked over the top of the female seam. Then a second seamer completes the second lock producing a one inch high profile double-locked at the top which is rolled over into the finished standing seam using hand crimpers.. This 16-oz. standing seam copper roof should have a 75 year life expectancy. Proper application is critical. Lack of provisions for thermal expansion such as permanently attaching the copper to the roof will create stress in the panel and eventually cause material failure. Also fasteners should be from the copper family or electrolysis will set up.

Jesse Gonzalez joins Bob at the Punta Gorda storm-ready home to explain the roofing process. The crew has already nailed on the 30 pound asphalt-impregnated felt paper. They are now hot mopping 90 pound roll roofing with asphalt adhesive to make it adhere to the felt paper below. Gonzalez shows Bob the decorative wood dormers on the front of the house that are wrapped in house paper to protect against water intrusion. Bob remarks on the decorative arches above the front entry porch and the front window. They mirror each other as design elements and will both feature decorative columns. Around the back of the house the crew is completing a section of roof deck. They are using 5/8-inch plywood sheathing for a stiffer, more wind-resistant roof deck. The crew uses metal plywood clips to align the plywood and keep it even for nailing.

Ken Langevin from Owens Corning tells Bob about the architectural shingles that have been selected to replace the old roofing material. The shingles are called architectural because they have a three-dimensional look, and they have a 40-year warranty because of the extra build-up of asphalt and mineral granules. Contractors find the shingles are easy to install. The ridge vent comes in a roll. It's rolled out on the ridge and attached with a nail gun. It has a wind driven baffle so any rain that does get in will just sit, and it's covered with the hip and ridge shingle to give it that architectural, three-dimensional look. They also installed an ice and water barrier on the ridge and eaves so that any ice build-up in the gutters won't be able to push up underneath the new shingles.