masonry

Green roofs are popular in many European countries. A green roof is a layer of vegetation planted over a waterproofing system installed on a flat or slightly sloped roof. Such roofs provide shade, remove heat from the air, and reduce temperatures of the roof surface, reducing energy use in the building and diminishing the urban heat-island effect.

A recent study by the University of Plymouth in the UK looked at the effectiveness of living walls – essentially the equivalent of a green roof located on the wall of a building.

The study looked at the effect of retrofitting an existing masonry wall with an exterior living wall façade consisting of a flexible felt fabric sheet system with pockets holding soil in which plants could grow.

Five weeks of measurements demonstrated that the amount of heat lost through the retrofitted wall was 31.4% lower than that of the original structure. They also found that daytime temperatures within the newly covered section remained more stable than the area with exposed masonry, so that less energy was required to heat that area.

The concept of living walls is fairly new but could be valuable in temperate climates such as Great Britain. Buildings in the UK account for 17% of greenhouse gas emissions and space heating accounts for 60% of all the energy used in buildings. So, improving the thermal performance of buildings would have a significant effect on reducing energy use and therefore emissions.

So-called green infrastructure, including green roofs and living walls, provides a nature-based solution that can help tackle climate change, air pollution, and other modern urban problems.

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Living walls can reduce heat lost from buildings by over 30%, study shows

Photo, posted June 19, 2011, courtesy of Linda Hartley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mass timber is a type of construction typically characterized by the use of large solid wood panels for wall, floor, and roof construction. Large structural panels, posts, and beams glued under pressure or nailed together in layers, with the wood’s grain stacked perpendicular for extra strength – are prized as innovative building materials, superior to concrete and steel in many ways. Mass timber has pushed the perceived boundaries of wood construction, leading to building heights and spans that traditionally have required concrete, steel or masonry for structural support. The move to mass timber has become something of a construction revolution and many see it as a significant part of a climate change solution.

The question is just how green is mass timber construction? How sustainable is it in terms of the forest management, logging, manufacture and transportation of wood products involved?

A number of environmental groups are very skeptical. There is not yet comprehensive data on the subject. Only recently have interdisciplinary scientists begun to study the potential climate impacts of the wide use of mass timber.

Despite these questions, the mass timber industry is taking off. Demand for mass timber posts and beams has led to new sawmills opening in the U.S. Northwest and many new jobs for loggers.

The aesthetics and economics of mass timber are both very attractive compared with conventional large-scale construction materials. The real unknowns relate to the environmental impact of its widespread use. If that can take place in a sustainable and environmentally conscientious way, it would be very important in the fight against climate change. Carbon dioxide emissions from the building industry account for more than a third of global emissions, primarily from the concrete and steel industries.

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As Mass Timber Takes Off, How Green Is This New Building Material?

Photo, posted March 19, 2018, courtesy of Freres Lumber Co via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.