By Mike Tonsbeek

There basically two types of roof tiles, clay and concrete.  The oldest types of roof tiles are made of clay.  Clay tiles have been around for many centuries dating back to the Neolithic period in China and later made popular by the Romans.  Concrete tiles were first created in the middle of the 19^th century in Germany and gained popularity in the middle of the 20^th century.

Clay tiles have basically remained the same over the centuries when they were individually handmade.  Today’s clay tiles are machine made, achieving more uniformity in both shape and color consistency.  They are available in a variety of shapes and styles and finishes.

Concrete tiles are also machine made for the same reasons as today’s clay tiles.  They have gained more popularity than clay in the current construction industry primarily due to cost but also due to a larger selection styles and colors compared to clay tile.

One of the biggest misconception of tile roofs, either clay or concrete, is that they virtually last forever.  It is true that the tile will last for many, many years; however, tiles are only one component of a tile roof system. One of the more important components of the tile roof system nowadays is the underlayment that the tiles are installed over.  Roof tile primary functions is to serve as a water shedding component, protect the underlayment from damaging elements and provide the desired aesthetics intended by the building’s architects.  

Roof tiles will continue to maintain their popularity for many years to come due to their proven durability and aesthetic values they provide.

DGBA Video Series: A Garden in the sky….

Not only are builders using metal roofs for commercial buildings, multi-family units and retail shopping centers but, more and more, cool metal roofs are being utilized for residential housing as well.

Metal roofs are on the leading edge of technology and are being sought after as an energy saving material for your home. They can improve the esthetics of your house and the can also provide long-term savings on energy costs.

So what is the difference between asphalt and metal roofing? Simply put, asphalt traps heat in the house while metal roofs reflect the sun’s energy and keeps heat away from the home. An unpainted metal roof will reflect much of the solar radiation which is usually absorbed in your attic.

‘Cool’ refers to the cooling aspects that the color coating provides on a metal roof.  So for homes in warmer climates like Dallas, a pre-painted or granular coated metal roofing system is recommended. These roofs not only reflect the heat, they also re-emit heat of absorbed solar radiation which can make your home’s temperature even cooler. Your home will stay warmer in the winter because the metal roofs are reflecting inside heat from the underside of the roof back into the home which adds up to a comfortable living environment and more savings for the homeowner.

There are additional advantages to a cool metal roof system that you may not have considered. Check out these 10 personal and environmental benefits of a metal roofing system:

1. Wide variety of ‘cool’ colors and finishes so you can customize your roof to meet your architectural style

2. Fire resistance can save your family and contents in case of a fire

3. Contain a significant amount of recycled material and are 100% recyclable

4. Can be designed to resist strong winds.

5. Low-maintenance and they do not warp, split or crack

6. They can be configured to catch rain water for harvesting systems

7. Are light weight and can be applied over an original roof saving waste and removal costs

8. Sustainable and have greater durability than other roofing systems which leads to a longer life cycle

9. Homeowner may qualify for a tax credit or insurance rebate

10. Most metal roofing systems come with a 20 year warranty

What is ponding water?  Ponding water as defined by the NRCA, National Roofing Contractors Association, as water that remains on a roof surface longer than 48 hours after the termination of the most recent rain event.

Long-term ponding water on a roof surface is one of the most destructive conditions that can adversely affect the life cycle of a flat roof system.  The UBC, Uniform Building Code, and the IBC, International Building Code, require that a flat roof surface deck is provided with a minimal sloping of ¼” per foot for proper roof drainage.  Most buildings are built with that requirement, however, while this sloping is provided at the building framing stage some sloping is lost when the with the adding of additional construction components that typically are suspended from roof joists or trusses such as ceiling, plumbing and electrical systems. Heavy roof top equipment such as HVAC, refrigeration and air circulation systems may also contribute to loss of sloping to the roof deck.

There are several methods of correcting water ponding issues on a flat roof.  The most effective is to provide proper sloping with tapered insulation or re-decking with rip-strip framing.  For moderate to severe localized ponding, layering additional roofing membrane can produce limited success, however, care must be exercised not to just to move the ponding issue to another location of the roof.  Another method to correct moderate to severe ponding, is installing an additional surface drain recessed in to a sump box at the deepest point of the ponding.  This method requires the enlistment of a plumbing contractor for feasibility and installation of a drainpipe to the exterior of the building.

Most roofing material manufacturers will void their product warranties when ponding water conditions exist.  There are a limited type of roofing systems were ponding water does not affect the roof system life cycle or manufacturers warranties. The use of these systems should always be explored.

One should always consult with a qualified professional roofing contractor when dealing with ponding water conditions on a roof.   Budget restraints may leave both the building owner and roofing contractor with limited options on the decision to choose the lesser of two evils in choosing the better solution to the condition.

MT

Yes, roofs of all types require periodic maintenance.  Most building owners do not proactively maintain their roofs, only calling for service after a problem arises such as interior water intrusion that usually also causes other damage to the building.

Proper proactive roof maintenance should always include a visual inspection by a qualified roofing professional at least once every two years; however, building owners can also conduct a bi-annual inspection themselves. 

The first thing persons inspecting a roof surface must do is employ proper safety practices in order to prevent injury to the person inspecting the roof, such as fall protection and safe ladder use.

The primary condition a building owner should look for is accumulation of debris on the roof that affects the proper drainage of the roof.  Any debris observed on the roof surface should be removed by hand and not by mechanical means such as a leaf rake, broom or a garden blower as these activities may cause unnecessary damage to the roof surface.

Next, all rooftop penetrations such as plumbing, attic and hood vents should be visually inspected for damage such as fastener displacement and failed waterproof sealing.  Damaged or unsealed vents are a leading cause of interior moisture intrusion.

All sheet metal flashing components at walls, chimneys and other vertical transitions should also be inspected for proper waterproof sealing at lap joints and corners.  Sealant failures at these locations are also a primary cause of interior water intrusion.

The roof inspection should also include visual inspection for any type of roofing material displacement usually associated with wind damage.  It is a good idea to inspect a roof surface after a wind event, as the damage may not be observable from the ground.

Trees, vines and shrubs should always be maintained away from the roof as far as possible in order to prevent contact with the roof surface, as this condition will lead to roof damage, roofing material displacement and subsequent interior water intrusion.

In the event that unsatisfactory conditions are observed on the roof it is recommended that a roofing professional be contacted for proper repairs.

(MT)

Asphalt shingles possess an overwhelming share of the U.S. steep-slope roofing market and may be reinforced with organic or fiberglass materials. Although asphalt shingles reinforced with organic felts have been around much longer, fiberglass-reinforced products now dominate the market.

Organic shingles consist of a cellulose-fiber (i.e., wood) base that is saturated with asphalt and coated with colored mineral granules.

Fiberglass shingles consist of a fiberglass mat, top-and-bottom layers of asphalt, and mineral granules. Asphalt shingles’ fire resistances, like most other roofing materials, are categorized by Class A, B or C. Class A signifies the most fire-resistant; Classes B and C denote less fire resistance. Generally, most fiberglass shingles have Class A fire ratings, and most organic shingles have Class C ratings.

A shingle’s reinforcement has little effect on its appearance. Organic and fiberglass products are available in laminated (architectural) grades that offer a textured appearance. Zinc or copper-coated ceramic granules also can be applied to organic or fiberglass products to protect against algae attack, a common problem in warm, humid parts of the United States. Both types of shingles also are available in a variety of colors.

This house has an ENERGY STAR ^® rated cool roof system in Dallas, Texas. The reflectivity property of the ‘cool metal roof’ allows this home to reduce its energy costs in the summer months. The roof was built so it sloped in one direction and can be used to collect rain water once a water harvesting device has been installed. The collected water can then be used to water the home-owner’s landscape, while conserving water and saving on utilities.

Photo credit: elgreco in bethesda

The Consortium for Research on Renewable Industrial Materials (CORRIM) at the University of Washington conducted a study on the environmental impact of lumber production.  They have interesting findings that might shock you regarding the sustainablility of wood.  Wood is among the most energy-efficient and environmentally friendly of all building materials.  Wood buildings are readily adapted and are a renewable resource, a characteristic of unparalleled value.  

CORRIM is a non-profit consortium of 15 research institutions formed to research the use of wood as a renewable material. In the study, CORRIM used typical building designs to construct hypothetical homes, and then compared the environmental benefits of wood-framed versus steel-framed houses in a cold climate and wood versus concrete in a warm climate.  The study looked at environmental effects across the entire life cycle of the home and produced the following results:

Energy Use:

• Construction of the wood-frame home used 17% less energy than the matching steel-frame home.
• Construction of the wood-frame home used 16% less energy than the matching concrete-frame home.
• The energy consumption measured included not just electricity, but also diesel and fuel oil to extract and haul materials, natural gas to generate steam in lumber mills, and electricity for steel mills.  

Global Warming:

• The global warming potential of the wood-frame home was 26% lower than the steel-frame home.
• The global warming potential for the wood-frame home was 31% lower than for the concrete-frame home.
• Using wood products instead of steel or concrete can further reduce greenhouse gas emissions from fossil fuels because more than half the energy used by wood mills comes from biomass – bark, sawdust and other residuals – a renewable source of energy.