Should my roof be torn off?
We generally recommend tearoff on most everything because you expose all of the old flashings and the possibility of the sheathing (wood) needing work. You can overlay a roof if it only has one existing layer on it. We don't recommend it very often. It must be in good condition - not curled or buckled. We tear off 95% of our roofs and overlay approximately 5%. Examples of tearoffs.
What type of shingle is right for my roof?
Asphalt is a thing of the past. Asphalt shingles used to be a primarily asbestos shingle, they have since changed these to an organic mat. This organic mat is similar to cardboard. It will absorb moisture, warp, swell and curl. The curled shingles may still have some life left in them. A fiberglass shingle has a thicker mat of fiberglass sandwiched between two sturdy layers of asphalt. Actually a fiberglass shingle has more weatherproofing asphalt than an old asphalt shingle. A fiberglass shingle will not absorb moisture. It will not rot, and it is more fire retardant then the old asphalt shingles. Fiberglass shingles have been around since the 1950's. Owens Corning started testing the fiberglass shingle on a home in Washington DC in the early 1950's. There are no companies that currently make an asphalt shingle.
What is the possibility of the sheeting needing work?
Most tear offs will have at least some wood that needs to reworked, renailed, or replaced. It is very hard to tell the extent of the work that will need to be done until the shingles are torn up. We try to get an idea how much resheeting wood will be needed by examining the roof. However, this is only an estimate of the actual amount of wood that will be used. Any good contractor will let you know up front how much any additional wood will cost, so that there are no surprises for anyone as the work progresses.
If there has been a leak, you can count on the wood in that area will need to be replaced. If there has been inadequate ventilation, the wood can mold and will need to be replaced also. Examples of sheeting.
Why is the single coverage interlocking shingle inferior... ?
Single coverage shingles are inferior simply because there is only single coverage. If a tree branch pokes a shingle, or you have a washout area, you will have a leak simply because there is only one layer of coverage. With the double coverage shingle, if something wears through the first layer, you will have a backup. Also single coverage interlocking shingles lock together at their four corners; each of these corners is an ice trap. Anytime you have ice buildup, you have the potential for a leak. The double coverage sealdown shingle sheds ice and water more efficiently, and has less potential for leaks. We will only install double coverage sealdown shingles. We feel that strongly about their superiority.
What is proper shingle alignment?
Proper shingle alignment is both vertical and horizontal alignment. Horizontal alignment is accomplished by snapping a chalk line across the roof. We snap a chalk line every two rows to keep a nice straight line. For the vertical alignment we either snap another chalk line, forming a grid, or we use a carpenters square to precut the shingles and make sure they are true and square before installing. Three tab shingles, like the Owens Corning Supreme, depend upon both horizontal and vertical alignment. Dimensional shingles do not require a vertical, because they are a random tab-less shingle. Example of proper shingle alignment.
How should the valleys be treated?
There are three valley systems common to roofing. One, is the half laced or California cut snapped valley system. Second is an aluminum or metal valley. Third, a laced or weaved valley. The laced or weaved valley is an inferior system because it tends to hold water and rot prematurely where the two panels are laced together. This system does not allow for proper water flow. The aluminum valley is subject to high expansion and contraction due to the intense heat and sun on the aluminum. This expansion and contraction tends to cause it to buckle and warp. Also after it has been bent to fit the valley there is only approximately 11 inches of coverage on either side of the valley. It is probable that snow, ice or water could slid down the valley and back up past those 11 inches leading to leakage. Also your shingle warranty ends where the metal begins. What we prefer is the half laced or California cut snapped valley system. In this system the smaller panel, or dormer panel, is run up on to the main roof, and then the main roof is run over top of the smaller panel. Then a chalk line is snapped a little bit high of center and the top layer is cut out. This gives you a clean, neat valley system that is less likely to cause problems in the future. Examples of valleys.
Should metal edge be used?
A good heavy gauge metal edge should be used on at least 99% of all roofs, on the rake edge and the drainedge. We use heavy gauge, two inch by four inch, hemmed drip edge. This gives us a good straight edge to work off of. It also keeps the water flowing into the gutters, and not down the side of you house. The only time dripedge may not be used is when ornate woodwork is used, or on a rustic log cabin. In an instance when dripedge is not used, the shingles are extended one inch further to provide the same action.
What about the soil stack and chimney flashings?
Soil stack flashing should always be replaced when reroofing a house. There are three styles of soilstack flashings.
- a plastic base with a rubber ring.
- aluminum base with a rubber ring.
- all neoprene.
Neoprene flashings can shrink and are the most susceptible to leakage during blowing rains. The aluminum base with a rubber ring can dry rot, crack and split also leading to leakage. The plastic with a rubber ring are a little more expensive, but they are the most durable. You don't want to call us back for a leak, and we don't want you to have to call us back. So we install the best products.
Unless the chimney flashing is a heavy gauge aluminum and bent into the brick it will be cut off and replaced with heavy gauge aluminum or sometimes copper. The chimney should be stepflashed and counter flashed with aluminum or copper as desired by the homeowner.
Flashing is a procedure that must be used around all roof protrusions; soilstacks, vents, etc. The correct flashing procedure is two shingles go under the flashing and the next two or three shingles are cut over the flashing. When the water runs down hill it will run over the flashing and not under it. Examples of good and poor flashing.
Should the roof be ventilated?
Yes, every roof should be ventilated. The only exception is a cathedral roof with a tongue and groove ceiling. The roof must be ventilated for warranty purposes. Ventilation helps prevent the attic space from overheating, causing the shingles to curl and shorten their life. Proper ventilation also helps to prevent condensation from forming on the inside of the roof surface causing water damage in the house. Click here for more information on ventilation.
How much ventilation is needed?
You can't have to much ventilation on a residential roof. One box vent is required every nine feet, eight to eighteen inches from the peak. Three feet of ridgevent is equivalent to one box vent. We prefer to use a continuous rolled, capover, concealed ridgevent that is maintenance free. Aluminum ridgevents have a seam every ten feet that is very hard to keep sealed water tight due to the expansion and contraction of the aluminum. Coravent, Ventsure and Trimline are our preferred choice of concealed ridgevent. These brands are easy to work with, they are not too soft to hold a good nail, nor are they so hard they are brittle.
|
