Your choice of roofing materials often depends on your locality, as much as on your own personal taste. In some regions, for example, metal roofing is a common selection due to its fire resistance, while in other regions, the predominant home styles might call for a Spanish-influenced tile tool. Roof pitch (angle) also affects the kind of roofing materials you can use. For example, wood shake shingles can be used for steeper pitched roofs but are not suitable for flatter, low-pitched roofs.
The most common choices for residential roofing include:
- Asphalt composition shingles: These are cheap and easily obtainable, but they are less attractive than other options due to their flat appearance. This is by far the most popular type of roofing material.
- Wood shakes or shingles: These are pricey but attractive shingles. They have great durability but aren’t a good choice in regions where there is a fire danger.
- Metal Roofing: Metal roofs made of steel or aluminum have become more popular in recent years, due in part to their durability and because they are fireproof. These are expensive roofs that require specialty contractors for installation, but they may be cost-effective over the long run due to their long life. Several types of metal roofing systems are available, including raised-seam panels and products that mimic the look of composite shingles.
- Slate roofing: This is a highly attractive, high-end roofing option, but it is expensive and very heavy. Slate roofs are extremely slippery to walk on and difficult to repair when damaged.
- Composition slate: These synthetic tiles made from 95 percent recycled materials, including rubber, are gaining in popularity. They closely resemble slate and other forms of stone tile but are much lighter and less susceptible to damage.
- Clay or ceramic tile: Long the most predominant image in Southern California and Florida, the so-called Spanish-style red tile roof is still common but is being gradually replaced by metal and composite materials that mimic the Spanish tile look. Other roofing materials are now available which meet ceramic tile’s fire retardant ability, with much less weight put on the roof. This type of shingle is called the half-barrel because it is essentially a cylinder cut in half length-wise, roughly 16 inches long.
Tear Off or Second Layer?
It was once common to lay a new shingle roof over the preexisting layer at least once, or sometimes even twice. This is no longer allowed in some jurisdictions, where complete tear-off of the previous roofing is now required. Even where layering is allowed, applying a new layer of shingles over the old should be carefully considered on the basis of its pros and cons:
- Weight: The main argument against laying additional layers of asphalt shingles is that the roofing materials can get too heavy for the underlying roof framing. This can be a structural problem, especially for older houses. It is often said that a triple layer of asphalt shingles is equal to a single layer of slate shingles—an exceedingly heavy type of material.
- Telegraphing: Another problem with shingling over existing shingles is that you are essentially repeating some of the surface irregularities that may already be present. If you’re contemplating putting on a new roof, there’s probably a good chance that you may have bubbles, bumps, and waves that should be remedied. Putting new shingles over existing problems can leave you with a rather unattractive new roof. One way to minimize this problem is to go over the old roof and correct as many problems as you can before re-roofing. It doesn’t take much more than a hammer, some roofing nails, and a handful of shingles to correct bumps, gaps, and protruding nails.
- Work and waste reduction: The primary advantage of layering is that it reduces the work involved. Stripping off the existing layer and then laying down a new layer adds more work to the process. This isn’t a real problem if roofing professionals are tackling the job—they can strip most roofs in a morning—but if you’re doing the job yourself, it can be a strong argument for roofing right over the old roof.