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Roofing Material Types

Roofing contractors on the job

Not long ago, asphalt shingles, slate, clay or concrete tiles were about the only roofing options. Today, advanced roofing materials provide an unprecedented range of alternatives, as well as new looks for existing materials.

Here is a list of 9 different types of roofing to consider for your next re-roofing job:
1. Solar tiles

Advanced solar collectors integrate seamlessly into existing shingles, generating up to 1 kilowatt of energy per 100 square feet. Theyre particularly good for sunny roofs in homeowners associations that forbid typical solar panels. While they may help offset energy costs with solar power, they also cost more than traditional solar options.

2. Asphalt shingles

Asphalt shingles are the most common roofing materials in America because theyre effective in all environmental conditions. Quality varies widely, so ask whether they pass the ASTM D3161, Class F (110 mph) or ASTM D7158, Class H (150 mph) wind tests and the AC438 durability test. Upfront costs are low, but you should expect to replace the shingles after about 20 years. If you live in a hail prone area, consider impact resistant shingles which have a UL 2218 Class 4 rating. Impact resistant shingles may qualify for a discount on your homeowners premium.

3. Metal roofing

Metal roofing comes in vertical panels or shingles resembling slate, tile and shake and lasts about 60 years. Metal excels at sloughing off heavy snow and rain, wont burn and resists high winds. It is lightweight and can be installed over existing roofs. However, metal can be noisy during rainstorms, and may dent from hail. Average costs range between $5 and $12 per square foot, depending on type and style of metal which is more than asphalt but less than concrete tiles. Corrosion also varies by material.

4. Stone-coated steel

Interlocking panels mimic slate, clay or shingles and resist damage caused by heavy rains (up to 8.8 inches per hour), winds of 120 miles per hour, uplifting, hail and freeze-thaw cycles. Consequently, theyre an economical, effective choice for wet, windy regions or areas prone to wildfires. Some stone-coated steel roofs are warranted for the lifetime of the house.

5. Slate

Slate roofing lasts more than 100 years. It wont burn, is waterproof and resists mold and fungus. Slate is effective in wet climates but is expensive, heavy and may be easily broken when stepped on. Keep this in mind if you live in an area that experiences hail.

6. Rubber slate

Rubber slate looks natural and can be cut with a knife to fit intricate roofs like those found on Victorian homes. Rubber slate roofs can last 100 years but can be damaged by satellite dishes and walking so may also be susceptible to damage by hail, similar to slate. Roofing professionals that are trained to install rubber slate may be hard to find.

7. Clay and concrete tiles

Clay and concrete roof tiles can withstand damage from tornadoes, hurricanes or winds up to 125 miles per hour and even earthquakes, according to "A Summary of Experimental Studies on Seismic Performance of Concrete and Clay Roofing Tiles" by the University of Southern California for the Tile Roofing Institute. They are good in warm, dry climates. They may require extra support to bear their weight, and they are likely to break when walked on.

8. Green roofs

Green roofs are covered with plants and can improve air quality, reduce water runoff and insulate homes to reduce urban heat islands. However, they need extra structural support, a vapor barrier, thermal insulation, waterproofing, drainage, water filtration, soil, compost and plants. Their estimated lifespan is 40 years.

9. Built-up roofing

This heavy roofing consists of layers of asphalt, tar or adhesive topped with an aggregate and is only for flat roofs. Tar and gravel roofs, also for flat roofs, are best for roof-top decks with heavy foot traffic. These roofs may become sticky in summer, and it is harder to shovel snow off of these roofs when compared to smooth surfaces. They can last 20 to 25 years. The best type of roof for you really depends on your climate, budget and house. To see whats best in your area, talk with licensed roofing contractors and look at some of the newer developments nearby to get ideas on what type of roofing material to use. Regardless of what type of roof you go with, there is always a chance it can be damaged. Roofing can be expensive, so you want to make sure youre covered when the unexpected happens.

How Trees Survive Cold Weather

tree with snow

Fossil records tell us that about 250 million years ago, trees were not able to live at temperatures below zero. It was only adapted to live in the tropics where it is always warm, the water is always liquid, and the leaves are safe year round without fear of frost.

If you took a tropical tree, whether ancient or modern, and moved it to Siberia or Patagonia in winter, its water would freeze into sharp edged ice crystals. They would fatally puncture the living cells in all of the tree's leaves. This is the same thing happens to lettuce and spinach when you freeze them.

The cold weather means that the water in the trees plumbing system freezes. Dangerous bubbles form in the ice from gases that was previously dissolved in the liquid water. The ice itself does not cause much harm. However, when it thaws the water remains, which is a problem because the entire plumbing system relies on the intramolecular attraction of water molecules pulling each other upwards against gravity. Air bubbles break the chain of molecules essentially shutting off the flow of water.

Therefore, to survive in cold weather, trees need to avoid two things:

1) Bubbles in its pipes
2) Direct damage to cells due to ice crystals

Trees solve the first problem before leaving hot climates, because air bubbles also are a problem during drought. When plants are working hard to get water from the soil, their water conducting pipes accidentally absorbed very small pockets of air from the surrounding tissue. To combat this, trees in the dry tropics developed skinnier pipes, which, thanks to the counter intuitive physics of bubbles and water, develop fewer bubble blockages than the wide high capacity pipes of their wet tropical cousins. Therefore, the plumbing of ancestral drought adapted trees was accidently pre adapted to the cold as well. This adaption occurred well before the trees began to spread beyond the tropics.

Upon arriving in cold places, trees developed two techniques that they still use to avoid frozen leaves. The first is to fill the living leaf cells with concentrated sugary sap, which is the biological version of anti-freeze. Some trees, mostly evergreen conifers like Pine or Spruce, use solely this technique and keep their needle like leaves unfrozen year round with their super strong anti-freeze.

However, some other varieties, such as maple, birch, and larches, combine a less extreme level of sugar in their leaves with a practice of going leafless during the winter to avoid foliar frostbite. These techniques are uniquely cold beating adaptations. That is until the decedents of leaf dropping trees made it back to the dry tropics, where their strategy helps them deal with the extended seasons of drought monsoonal climates.

As far as we know, sugary sap remains the only adaptation that is only useful in cold places. Which is why you have to come to the north if you want to tap into the sweet anti-freeze that might just help you survive the winter. We call it Maple Syrup, and it is delicious.

To learn more about caring for your trees during cold weather contact your local tree service expertslocal tree service experts.