Roofing Replacement – The Seven Basics
There are seven Basic elements in your roofing. The Support, the Deck, the Underlayment, the Roof Covering, the Flashing, the Ridge Vents, and the Design.
1: The structure under your actual roofing; the support beams (rafters, trusses), typically in the attic, that support the roof structure from underneath. You need to conduct a thorough inspection of your home’s attic, or have it done by a professional and go with them to see the condition for yourself. If your supporting structures are warped, rotten, insect ridden or otherwise damaged, you should not consider replacing what’s above those structures until you address the quality and strength of your roof’s supports.
2: The Deck: which is sometimes called sheathing; that’s the wood (typically plywood panels) or metal sheeting attached to these supports. When you eventually choose a roofing contractor and sign a contract, be sure it specifies the cost that contractor charges to replace any panels. Neither you nor your contractor will know how many, if any, panels are damaged and in need of replacement until the contractor removes the old roof covering materials. We suggest that you ask your contractor to specify in the contract how many panels they’ll replace for free, along with the cost of additional replacements. This avoids confusion or any feeling that you are being taken advantage of with ‘hidden’ costs.
3: The Underlayment: It’s that material that looks like black paper or felt that covers up the Deck panels. It’s often saturated with asphalt and provides moisture and air barrier lay over the deck.
4: The Roof Covering, typically Shingles or Tiles, which are the exterior elements that come into direct contact with the elements. They are your home’s first line of defense against rain, snow, ice, hail and high winds. In the United States, the most popular covering by far is Asphalt Shingles, but roof covering can also be clay or concrete tiles, wood, metal or a synthetic material. For more about Asphalt shingles, refer to our Tutorial called “Asphalt Shingles”. Newer technology incorporating fiberglass has revolutionized asphalt shingles and greatly improved their performance and lifespan.
5: The Flashing that waterproofs and weather proofs those parts of your home most likely to collect water or leak. This is especially true with anything that protrudes through your roof, like your chimney, skylights, exhaust events. Also, edges of your roofing or the ‘valley’ where two sloping sections of roof connect are locations where water or snow will naturally accumulate, so flashing can help protect you from that water.
Flashing is usually sheet metal that is bent and formed to provide that barrier between your roofing and whatever is protruding through it. It can be galvanized steel, stainless steel, aluminum, copper or some other metals, or a synthetic material. The formed flashing has to assure that water can not penetrate into or through your roofing system. Water can find its way into your roofing by gravity, by surface tension, or by high winds that actually drive it upwards.
6: The Ridge Vents that typically sit at the highest point of your roof, to allow for air flow through your attic. The Ridge vents help balance the temperature between outside and inside, which can help prevent damage like a warped deck or cracked shingles. A properly ventilated attic is a key to a healthy roofing system. These ridge vents atop your roof will be covered by materials that match the covering you choose. For example, if you cover your roof with shingles, there will be matching shingle material covering your ridge vents.
7: The Roof Design: The shape, arrangement and slope of the different sections of your roof that determine its ability to shed water and withstand infiltration of air and moisture. For more details about Roof Design Terms, refer to our Tutorial called “Roof Design Terms”. For general purposes, just realize that the complexity of your roof’s design, the more individual sections, the more protrusions, overhangs, et cetera, that more material and labor will be needed to properly complete your job.
I hope this helps you get started, and feel free to drop me a line about your renovation project. Good luck and enjoy your home!