So, your roof has finally succumbed to the numerous climatic beatings that have accumulated in roof repair over the years. You’re ready, willing and able to make an ecological stand around your home and would love to start immediately – the problem is, green roofing materials are seemingly everywhere, and knowledge of sustainability baffles you.We’ve done the dirty work of locating the most ecologically-friendly roofing materials and list these in order of highest* thermal resistance, known around the block as R-Value.
Sprayed Polyurethane Foam (R-Value: 6.88 per inch)
First used in 1940’s military aircraft, polyurethane foam is one green roofing material that offers far less air escape than shingled roofing systems. At 1” in thickness, expect 40% of your home’s unannounced air loss to come roaring back, significantly reducing your energy bills all year long. When used as an underlayment (below conventional roofing materials, above oriented strand board decking), expect your R-Value to increase significantly while maintaining polyurethane’s moisture control properties. Today’s applications are completely eco-friendly and emit zero CFC’s.This sustainable material is also commonly used in commercial roofing applications, although residential dwellings stand to see considerable savings that commercial buildings cannot touch, in using polyurethane. While the cost of SPF roof applications may be high, the benefits are higher.
Extruded Polystyrene (R-Value: 5.00 per inch)
Those residential dwellings often plagued with rainy seasons would find XPS, or extruded polystyrene, perfect due to a consistent yet highly hydrophobic closed-cell assembly that’s resistant to water intrusion. Because these closed cells are surrounded by microscopic ‘voids,’ water absorption is much quicker than similar materials; when paired with proper sealing agents, these voids can easily soak up moisture that – you guessed it – could begin warping your OSB after 10 years.Since polystyrene comes in uninteresting white panels, you’ll need to either use this as underlayment or paint it to suit your color needs.
Thermoplastic Membranes (R-Value: 4.55 per inch)
Thermal insulations work best in low-sloped roofing applications, but they are growing in residential usage due to their highly reflective nature. Energy savings are achieved through highly emissive panels constructed with solar reflectivity, which disburse cooling loads throughout residential dwellings and work equally well atop commercial buildings.When assessing whether thermoplastic membranes would help your home, certain climate and size considerations should be taken into account. For example, seasonally-cooler areas like Seattle or Great Falls may not reap full benefits of this roofing material. These eco-friendly panels have a slight uptick in cost, yet this levels out when bills come in much lower than before.
Dimensional Shingles (R-Value: 1.69 w/ ½” plywood)
Dimensional shingles, which are much different than your standard three-tab, are generally what residential homes use. Designed for both looks and functionality, these roofing materials require two levels of underlayment: felt paper and either 7/16 or ½ plywood. OSB (oriented strand board) and CDX are common roofing plywood.
These shingles are not designed with a heavy R-value in mind. As they’re more affordable than thermoplastic or thermoset, builders can replace or repair roofs without passing on a huge expense to the homeowner. Architectural shingles last between 25 and 40 years, with costs that vary by region.
Copper Roof (R-value: variable)
Both malleable and ductile, copper in roofing applications is growing in popularity as it aesthetically enhances homes in ways architectural shingles cannot. These roofs theoretically could have a lifespan of up to 1000 years.
Copper roofing is simple to repair, much easier to work with as it requires no caulking, bends well around tight or irregular areas in roofs, and could even provide long-term ecological benefits to homeowners. R-values of copper will vary because copper sheets heat and cool much differently than standard roofing applications.
Watch. Learn. Construct.
With the popularity of television shows featuring large-scale renovations and rebuilds, the topic of energy efficiency has become widespread. New homes are increasingly moving towards a “passive” solution to heating and cooling, where eco-friendly roofing materials are utilized to enable a property to stay cool in the summer and warm in the winter with a minimal (or zero) outlay in energy bills.
Anyone interested in seeing how roofing materials might be utilized to stay congruent with eco-friendly values may be fascinated by seeing homes constructed with sustainable roofing materials, asking homeowners, questions about energy savings, then deciding which material is more suitable. Note that these three materials can be used in place of 15# felt paper, in conjunction with insulation or as standalone roofing materials.