It was just this fall when the rain storms hit that I was again reminded how important it is to keep your roofing maintained. As a matter of course we inspect all roofs at least twice a year, but recently we ran into a major leaking problem with a new commercial tenant. The building had a jumble of roofs, and of course once the rainy season started, we had nothing but leaks in their space that made it almost impossible to use. Our maintenance team followed normal procedures cleaning the gutters, downspouts and drains which normally solves the leak problem, but this time to no avail.
The roof leak could not be found; we agreed to install a new roof. In the process of the installation, we discovered that water had leaked behind the roof flashing of an exterior wall and was pouring into the crawl space. With the leak identified and repaired, the tenant can again run their business. Good roof maintenance is key to avoiding costly leaks and water damage. Understanding the construction, materials and style of your roof is a good starting point in identifying and avoiding potential problems.
To introduce this conversation you need to know that there are many kinds of roof styles: Shed, Hip, Mansard, Gable, Gambrel, Saltbox, Flat are some of the most popular.
Attention to Roof Care
There are many different kinds of roofing materials used all over the world. They all have different attributes, costs and aesthetics, and all need constant attention to insure long-term life. Many roofs are designed to be replaced in 15 – 30 years, but some can last anywhere from 50 to 200 years. The environment surrounding a roof also has a significant impact on the length of roof serviceability. The south side of many roofs often has more wear from the sun which can reduce the lifespan of a roof. Inadequate attic ventilation can create a damp atmosphere that has a deteriorating effect on roofing. Tree branches overhanging or in contact with roofs need to be cut back, due to not on the leaves and debris that fall on the roof, but also the wear created by the branches and the pathway provided for insects to travel to your building. Roofs framed with lumber attract pests that can destroy your roof. Just imagine the squirrel that decides your roof drain or gutter is a good place to call home and uses it to store nuts, causing the water to back up and flood the inside.
A common residential roof is asphalt /fiberglass shingle roofing, also called composition roofing. This type of roofing has a lifespan of 15 to 40 years depending on the quality of roofing installed. It consists of a rag fiber or a fiberglass mat impregnated with asphalt and covered with colored mineral granules. They come in a wide variety of colors, designs and weights. Standard style shingles can be roofed over up to 3 times, but architectural shingles must be torn off in order to be replaced due to the unevenness of the surface. Asphalt roofs show their age when the mineral granules wear off and the corners and the edges of the shingles begin to curl and crack. The first sign of problems usually shows up in the valleys of the roofing where the most wear and tear is due to water run off by the rains. The granules are there to protect the asphalt from the ultraviolet rays of the sun. Asphalt roofs need adequate ventilation to keep humidity from pushing them off of the roof.
Wood shingles, commonly made of cedar, cypress and redwood, are highly rot-resistant and may last 30 – 35 years if property installed and maintained.(including regular roof cleaning and oiling.) The sun tends to dry out the roof shingles and they will split. As wood shingles and shakes age, they may shrink and become brittle and form gaps between the shingles. Unusually only single tiles fail and can be individually replaced. The ridge cap on a wood shingle roof is the most susceptible to warping and splitting, and should be replaced as soon as warping appears.
The best wood roofing materials are also pressure treated with a wood preservative and fire retardants. Builders use wooden shakes for the look as well as for its insulating qualities. Dealers of wooden shingles also encourage their use due to their light weight in earthquake-prone areas, and also because wood can withstand extreme temperature changes.
This roofing material is found mostly on the east coast of North America. Slate is still being quarried in Virginia, Pennsylvania, New York and Vermont, (though Slate quarries existed in Maine and Georgia). Each quarry delivers a different kind of slate so it is important to have a slate expert guide you. There is also a “Slate Roof Bible” ( www.jenkinspublishing.com) that can instruct you.
Life expectancy of slate can exceed 150 years. In England some slate roofs have been know to be in place in excess of 800 years. Winters can be particularly hard on slate roofs. Heavy ice and snow can slide off the roof carrying with it the slate tiles roof. That is why on many slate roofs you will see small metal projections sticking up. They break up the snow and ice, allowing it to slide off of the roof without causing damage.
General signs of wear are delamination, discoloration, fungi growth and slipping or dislodged slate. Cap courses on the ridges and hips are most vulnerable to seepage. A great online reference is www.jenkinspublishing.com.
Cement and Clay Tile
Cement and clay tile roofs have existed in the southern latitudes for centuries. Ancient Egyptians, Greeks and Romans used tiles for their roofs. They are considered durable, fireproof and weather resistant, though with the mission or barrel design wind-driven rain may create some leaking. With such tile roofs contractors recommend a sub roof. Modern “concrete” roof tiles are usually flat and are used in the place of wooden shingles where owners are concerned about fire hazards. Lightweight shingles of this variety are usually not used in areas with heavy snow loads.
Tiles have to be regularly maintained. They tend to be brittle and crack when you walk on them. Even though the Tile Institute thinks that tile weight is not an issue for roofing, in commercial applications I have seen roof trusses bow if the structural engineer did not run their calculations properly. This usually occurs when air conditioning units are also nestled in the truss spaces. As with slate roofs, tile-roofing specialists should be the ones to take care of you tile roof.
Metal roofs are resistant to environmental damage; they are highly fire resistant and require limited maintenance. Materials used include copper, tin, aluminum or other alloys with combinations of the metals. Typically they come installed with a baked-in paint color. Metal roofing has many advantages. For example, metal roofs have a lower life cycle cost than most traditional roofing material such as asphalt or cedar, and they can withstand severe weather such as hail, snow, high winds as well as fire. Metal roofs can initially cost three to four times more than traditional roofing materials, but property owners should keep in mind that the typical asphalt or cedar roof requires replacement every 15 years. Metal roofs, however, may last up to 60 years.
Most flat roofs are used in commercial settings, but there are also flat roofed apartment buildings. Because the roofs are flat roof drainage is important. If your roof ends up with a big lake because it does not drain, the water will find a way to work through your roof covering. (Note: there are some roofs designed to retain water. It is urged that the deck design be particularly stout due to the weight of the water and that the roof is drained in the fall to prevent winter freeze damage). Leaks, when they do occur, are difficult to locate and therefore difficult to repair.
There are many types of flat roofing systems. Below noted are three popular types:
Built up roofing systems also called BUR has been a very reliable product. It is not unusual to have many layers of roofing alternating hot melted Tar and special fiberglass roofing paper to hold the tar in place. Typically four to five layers create a minimum layering though layers of up to 6 are not uncommon. Generally, built up roof membranes are surfaced with a mineral aggregate and bitumen, a liquid applied coating, or a granule-surfaced cap sheet. This roof also works well where there are many air conditioning units and the roof sees a lot of traffic. In some cases you can also get a good fire rating from a built up roof.
Modified Bitumen roofs also called torch down roofing, is a self-contained, complete roofing and waterproofing system in rolls. The product is composed of spunbound polyester fabric sandwiched between two layers of APP modified bitumen. It is greater than 150 mils thick, possessing superior heat resistance, low temperature flexibility and excellent workability. It offers both good elasticity and outstanding tensile strength. It is applied over a roofing deck with an overlap that then is fused together with a torch, thus the name –torch down. It does not need a kettle of hot tar to apply and is more convenient for some roofers to use. It does not have the same class fire rating system as built up roofing. This product is tough, puncture-resistant, and also good for a roof with heavy traffic.
Single ply systems:
- Fully adhered
- Partially adhered
- Loose Laid
- Protected membrane roof
- Mechanically -fastened
The Durolast membrane is classified as a co-polymer alloy and is a proprietary thermoplastic formulation consisting of resins, plasticizers, stabilizers, biocides, flame retardants and U. V. absorbents. The membrane is laminated to a weft insertion knitted scrim. Roof Maintenance Finally, all roofs need care and attention. All roofs should be cleaned off at least once a year and inspected visually at that time. Gutters and downspouts should be cleaned at least twice a year in the fall and in the spring. Mold, mildew and algae should be kept off of roofs. Moss can be removed with a solution of zinc sulfate. Some people use zinc strips at the ridge caps for moss control the reaction between the rainwater and the zinc forms a mild chemical solution that is carried over the roof and retards the formation of moss, fungus and mildew. Roof care is a critical ingredient to insuring your investment. This primer gets you started and a good roofer will finish the project for you.