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THE WESTERN PRODUCER | WWW.PRODUCER.COM | OCTOBER 27, 2011
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HOME RENOVATION | ENVIRONMENTALLY FRIENDLY
It’s not easy being green when choosing how to renovate ENERGY FIELD
WILL ODDIE
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enovating is part of the human condition. Whether it was adding branches to the temporary hut, putting more thatch on the roof or enlarging our one-room soddy, we have been renovating ever since we developed shelter. Environmentally conscious construction often focuses on new buildings, but maintaining and renovating an existing building can be more green than new construction. Lots of resources are involved in construction, both material and energy. Demolition and removal to a landfill requires lots of energy, while rebuilding with entirely with new materials adds a greater environmental load to a project. What renovations and new construction have in common is the selection of environmentally friendly materials. For example, air quality is no less important in a renovated building than in a new one. Only painting? Use low VOC paint. Flooring? Consider using long-lasting hardwood, tile or bamboo. Carpets? Use those made from recycled pop bottles. Cabinets? Use those that do not off-gas formaldehyde. If the changes are mostly cosmetic, such as painting, consider a primer paint that acts a vapour retardant. However, if your house is old, the many layers of oil paint may already be doing a good job. Buildings that are made air tighter may need heat recovery ventilation units that exhausts moist air and preheats the incoming replacement air. Many attempts to fill existing wall cavities have been tried over the years, including the ill-fated and banned urea-formaldehyde. Blown cellulose has been used with holes drilled from the inside or outside. However, there is no method of insitu insulating that has proven to effectively fill the cavity. Crossblocking or wiring often causes material to hang up, meaning there are voids in the wall. Adding enough insulation to dramatically reduce your energy bill will likely mean removing the inner wall material or the outer wall material.
If you decide to “go all the way” with the exterior wall, you can add foam insulation sheets and carry the insulation, below-grade quality, right down the basement wall to the footing. If you go with the interior wall, you will have to remove the trim, being careful with dry and brittle material if you plan on re-using it. Then you have another choice: install foam sheets over the existing studs or build another inner stud wall set in from the existing wall and fill in the space with batt or blown cellulose insulations. You may have to add extensions to window and door jambs. Modern living often calls for more open design. However, make sure
walls are not load bearing before removing them. Central walls are likely to be load bearing in older houses. It is still possible to remove most of the wall, but a beam will have to be installed to carry the load. It is best to consult an engineer or competent contractor. Increasing R-value Attic insulation is easy with batts and even easier with blown cellulose, which is available at many retailers. The weak spot in older houses is the edge where the space is so minimal. If you want to improve the level of insulation in that area, one solution is to install a minimum 1.5 inch layer
of foam sheeting polyisocyanurate. It provides the most R-value, R5 per inch, on the whole ceiling. New drywall boarding then goes over that. Such sheet foam also serves as an airvapour barrier. Windows are often the focus of upgrades, but it doesn’t mean that replacement is the only option. Many good windows are trashed, but significant improvements can be made by careful weather stripping. New developments have also been made in low ‘E’ storm windows. Keep in mind the appearance of new windows in the context of older houses. If they are on the agenda, homeowners must decide whether to use box units inside the original
jambs or remove the jambs and go back to the framing. Sealing around window units goes a long way to stopping air leakage. Older buildings are not inherently better. In lots of cases, old construction was inferior to current construction. However, older buildings often have character, including the style of design, materials used and detailed craftsmanship. Renovating can improve livability and energy efficiency but it is always challenging. However, it is also rewarding if you can do it green. Will Oddie is a renewable energy, sustainable building consultant with a lifetime interest in energy conservation. To contact Oddie, send e-mail to energyfield@producer.com.
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Weigh the pros and cons Inside or out, sometimes a decision becomes obvious. If you have a beautiful, old brick veneer house, you are not likely going to want to remove that brick. It has a large embodied energy, would be extremely costly to replace and holds out the hot days of summer. On the other hand, the decision may be easier and different if it is a 1950s bungalow. Removing the outside wall finish would be less of a loss and much less disruptive. Upgrading the insulation will be a major job, whether it is done inside or outside, and some waste will be produced from the removed material. However, the long-term energy savings swing the balance toward being green. access=subscriber section=crops,none,none
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