Archive for the ‘Green Building Techniques’ category

Green Building Illustrated: Book Review

September 24th, 2014
Green Building Illustrated

Green Building Illustrated

Francis Ching is a well-known author and illustrator of books on design and construction, perhaps within the building sector his most well-known book is Building Construction Illustrated. Collaborating with Ian Shapiro on this latest book, the pair have developed a good introduction to green building for those just becoming familiar with the field, but it also serves as a good reference guide to green building for those of us with more experience.

“What is green building?”

The point of the question is to highlight the reality that it is really an evolving definition. Some buildings built to a high standard, have, upon evaluation, turned out to be less green than their standard counterparts because they use more energy than the comparative standard, whereas some net-zero or close to net zero buildings aren’t classified as green because the owner has decided not to go through the hoops necessary to become classified.

Further,  the authors address why building greener buildings is important, referring to climate change effects as well as resource depletion. They also delve into the different green classification systems that are available.What I like about this book is that after reading it you gain a basic understanding of all the elements involved in building a better, more resilient, lower impact building.

Hosting a Design Charette

Shapiro and Ching emphasize that with the development, design and construction of any building, there are thousands of decisions that are made. One decision affects another, so it means that there are trade-offs for every decision. Getting the design done right at the beginning can save time and money down the road and one of the best ways to do that is to have a design charette. A charette is like a round table discussion where every involved party can have a say in how the design will affect their portion of the building from plumbing, electrical, HVAC concerns, material selection, and occupant use post construction. Ideally charettes include the architect, general contractor, sub-trades, building owner and manager, in other words, all stakeholders.

The book is clearly illustrated and dedicates a good section to design and design issues. Getting the design right is one of the best ways to have the most significant impact on constructing a lower impact building. Again the book is thought-provoking: the authors ask “green buildings are lower impact than what?” In fact Shapiro gently takes LEED to task because the system fails to give points for designing a building that has a smaller surface area (therefore less exposure to the elements), than its standard counterpart. In other words, no points are given for designing a more efficiently shaped building than might otherwise be built. The authors explain the differences between the different green building rating systems out there, including LEED, Passivhaus, Living Building Challenge, and Green Globes.

Another perspective of the book is that it teaches readers to design buildings from the outside in, in layers. So, it looks at landscaping, site and orientation and how those factors affect the design of the building. Further, Shapiro and Ching highlight with detailed drawings, the importance of surface area on the energy efficiency of a building. In general terms, the smaller the surface area, the greater the energy efficiency of the building.

It takes only one brief glance at the chapter on windows to confirm that all those glass condos going up all over Toronto and Montreal are  an energy efficiency nightmare. Windows, in addition to having terrible insulation values, also pose potential leak problems between their frames and the building. If not sealed properly there is an extra source of potential drafts and water infiltration.

The chapter on building materials emphasizes the need to consider local, recycled and other materials with a low embodied energy. There is a handy table that shows the different embodied energy of different types of wall constructions.

One of the best features of this book is that it is an all in one reference guide for looking at how to build better buildings from design through to commissioning (evaluating a building’s systems to make sure they are all functioning properly). Once read cover to cover, it can be used as a reference guide to greener building and the different factors that need to be taken into account. While the book does not delve deep into any one area, it does provide a readable and approachable overview that’s easily understood by laypersons as well as professionals familiarizing themselves with green building practices. If I have one complaint, it is that for old people like myself, the spidery, handwritten style font is difficult to read.

Green Building Illustrated is available through John Wiley and Sons, or Amazon.

A Straw Bale Home Q&A with the Fourth Pig Sustainable Builders

July 7th, 2014
Rear view, straw bale constructed home addition

Photo courtesy of Mick Paterson. Rear view, straw bale constructed home addition, before exterior cladding

 

About a month ago I posted an article written by Terrell Wong, an architect specializing in sustainable building and design, about a straw bale addition to a home she had designed. She was frustrated because the city of Toronto denied it even though the city had built a straw bale building in High Park. One of the reasons the structure was denied was because the design doesn’t use a vapour barrier. The theory regarding a vapour barrier is that it is necessary to prevent water vapour from permeating walls and getting stuck there leading to mould and mildew problems which could eventually cause significant structural deterioration — not to mention indoor health problems. But straw bale building has been around for a lot longer than vapour barriers and homes built from straw have been around for hundreds of years in Europe and still stand today. What that indicates is that as long as you know what you are doing, straw bale homes are perfectly safe, healthy and durable, contrary to what someone unfamiliar with straw bale building might think.

After I posted the article, I was contacted by Mick Paterson, a project manager with The Fourth Pig, a co-operative sustainable building not-for-profit group based in Baysville, Ontario. He is currently overseeing a straw bale addition to a house in Toronto. They received approval from the city just as he contacted me, so his project was good to go.

I took the opportunity to visit when I was briefly in Toronto in June, to get a feel for a straw bale home and to ask questions that tend to come to mind when thinking about straw bale building. After the tour, I sent the team my questions and concerns — which I think are fairly representative of straw bale novices like myself. So, below are my questions and concerns, followed by Mick’s and his team’s answers.

 

Side view of straw bale addition and original house.

Side view of straw bale addition and original house.

1. The straw goes moldy after a while and can lead to such problems as black mould and wall collapse.

Fourth Pig:  Moisture is the enemy of any type of construction. The straw bales would only become moldy once prolonged heavy exposure to moisture is seen. A straw bale home must have a breathable protective coat. Lime and clay based plasters provide protection from bulk moisture while allowing any absorbed humidity to escape from the wall.

2. Straw can’t act as an insulation material.

Fourth Pig: Straw can be classed as one of the oldest insulation types on the planet. Straw has been used in Europe for centuries for insulation in different forms but straw bales as a wall construction and insulation really took off in the US in the mid-19th century.  Its r value is dependent on the bales compaction, orientation and construction detailing. The most agreed upon r value is 30 for 2 string bales or 1.4 to 2.6 per inch.

3. Its fire rating is low and therefore unsafe to use as a building material.

Fourth Pig: Both ATSM in the US and CSIRO in Australia show testing on straw bale walls to have a high resistance to fires with a 2 hour fire rating on plastered walls and 30 minute rating on an exposed strawbale. There are several examples of commercial straw bale buildings word wide. In Australia there is a veterinary hospital and in Colorado a Waldorf school chose straw bale as the only wall material for all 22,000 sq. ft. of its classrooms.
4. You need a vapor barrier to protect the straw from moisture.

Fourth Pig: Vapor barriers are not necessary for a straw bale wall as the plaster skin provides a similar function. As an added benefit lime and clay plasters allow the straw to absorb and release water vapor on both sides of the wall, preventing damage from accumulation. This happens in cold to hot climates, and dry to humid ones.

5. What is the best material to use for covering up the straw bale and why?

Fourth Pig: Natural plasters like lime and clay provide the most benefits for straw bale walls for their breathability qualities. Various factors such as design, cost, performance and historic longevity have shown the benefits of using lime and clay and avoiding cement and acrylic based plasters or covering the straw bales with drywall.

Straw bale wall

Close-up of Straw bale wall

6. Can straw bale be used for houses that are more than one story high?

Fourth Pig: The limits to how high you may build a SB wall are the same limits all buildings face. With intelligent design a skyscraper could be constructed with a façade of strawbales. (We would like to retrofit a multiple storey building with strawbales!)

7. How long does a house made with straw bale generally last?

Strawbale walls and all buildings will last as long as the buildings inhabitants make them last. All buildings require regular maintenance and upkeep as do strawbale walls. With proper design and upkeep SB walls can last for centuries or more. There are strawbale homes in the US that are still standing and in great condition from the mid to late 1800s.
8. Is it more or less expensive than building a stick built house?

Straw bale walls can be cheaper than regular insulated wall construction but there is so much variation of wall finishes and detailing that that need to be taken into account when trying to compare apples to apples. You will not get an R30 insulation value out of a traditional stick framed wall.

 

For more information on building a straw bale home, or have more questions about the material’s durability, visit the Fourth Pig’s website, or contact them directly.

 

 

Making Better Buildings Book Review

May 26th, 2014
Making Better Buildings

Making Better Buildings

I was asked to read and write a review for Chris Magwood’s new book, Making Better Buildings. I have written a good deal about the work that Chris does in the field as the director of the Endeavour Centre, a spin-off of a green building program that was developed at Sir Sanford Flemming College in Peterborough. Chris has substantial experience in using better, greener building materials and has used his knowledge to write this book.

The book is indispensable for anyone wanting to build a home using lower impact materials than today’s standard code-built home. The materials are classified by category for use in different phases of building, including foundations, walls, insulation, windows then roofing. Most of the book’s emphasis is placed on the materials used for the building envelope but there are also sections dedicated to different types of residential renewable energy generation, HVAC systems and interior finishes for floors, walls and counter tops, etc.

Chris describes how a material is manufactured including whether it’s harvested, mined, developed from chemicals, etc. You get a clear understanding of the overall environmental impact of a material.

One of the dilemmas I face when I write about materials is just exactly how green a material really is. With this book you can compare different types of foundations by how much embodied energy they contain as well as other environmental parameters.  A foundation made from earth-bagged forms has a “sample building embodied energy” of 0-16,665 megajoules while a foundation made from old tires and rammed earth (8% concrete) has a “sample building embodied energy” of 0-29,216 MJ. The variation depends on whether the materials are virgin or sourced on site and repurposed. This type of  material analysis is done for every material listed in the book so that each material can be compared consistently to another within the same category.

What Chris’ book does is thoroughly analyze materials in a way that helps novice and experienced builders decide which material will work best for their project and the impact on the environment that each material has. There is a chart for each material that identifies and rates on a scale of 1-10, not just embodied energy, but also,

  • overall environmental impacts,
  • waste generated,
  • energy efficiency of the product,
  • material costs,
  • labour inputs,
  • skill level needed by homeowner,
  • sourcing,
  • durability,
  • building code compliance and
  • indoor air quality.

By taking an analytical perspective, Chris remains impartial to each material. Note that he leaves out common building materials such as poured concrete foundations because their environmental impact is so detrimental.

Chris has created a list of pros and cons for each material to help you understand why one material might be more widely used than another.

If you are interested in building a home with a lower environmental impact  than the current standard built home offers, this is a great reference guide to help familiarize you with all of the latest lower impact materials currently available for building a home.

You can purchase Making Better Buildings through New Society (the publisher)’s website.

 

Skylights’ Function in The Active House

March 12th, 2014
Velux skylight operable with blinds

Velux skylight with blinds and operable glazing

Some green builders and energy auditors would argue that skylights have no place in a “green” home. After all, skylights puncture the building envelope allowing heat to escape in the winter and enter in the summer. Improper installation of skylights can add problems such as condensation build-up inside and ice damming outside.

However, in a house built to Active House standards, energy is an incorporated into the design but is not the driving component.  An Active House balances energy efficiency and human comfort by allowing natural daylight, fresh air and summer cross breezes into a building, while excluding excessive heat, cold, and glare from direct sunlight. This goal naturally means the home will have an abundance of windows and skylights — a direct contradiction of building philosophies such as Passive House which requires extremely tight building envelopes.

There have been many studies done on the positive effects of natural daylight on people’s health, and for those of us who live in northern climates and have suffered, even a little, from seasonal affective disorder, they will recognize the value of natural light, especially in the winter months. So while building envelopes are compromised with the addition of skylights, other green building goals are more than satisfied.

VELUX, a company established in Europe over 70 years ago, is well-known for its high-quality skylights. It has been involved with the Active House philosophy since its inception. I spoke with Nels Moxness and Russell Ibbotson of VELUX about the roles of skylights and their pros and cons in any building.

There are four major issues/concerns people have with skylights: air tightness, insulation value, solar heat gain and glare.

Air tightness: It’s no secret that many people who have lived in a house with skylights have experienced leaking at some point. While it can be due to faulty installation, often it is because the original skylights were installed using tar as the sealer around the flashing. Nels told me that after a few years of exposure to weather elements such as heat, cold, sunlight, water, snow, etc., the tar shrinks and cracks allowing water to infiltrate and find its way into the house. VELUX has always used a an engineered flashing which does not require sealants to maintain water tightness.  Their current product has the addition of  a rubber based membrane, which provides a shield from ice and water that often outlasts the roof’s shingles and prevents leaking. Further, to ensure proper installation of its skylights, VELUX certified installers  are required to attend a comprehensive installation training as well as have a job site inspected upon completion.

Insulation: With respect to insulation values, VELUX skylights are double-paned, flat glass, LoE³  that are filled with argon gas. This provides for a better insulation value than uninsulated skylights. The U-value for the installed skylights in the Active House in Thorold, Ontario is rated at 0.4 in Energy Star zones A, B and C (most of Canada’s population lives within these climate zones, Zone D, the coldest, covers the Arctic).  Note that there are 14 skylights in the Thorold house and the house achieved 1.6 air changes per hour. To give you an idea of how that compares to building code, the upgraded Ontario Building Code, 2012, and the newest Novoclimat (Quebec) building code require a minimum of 2.5 air changes per hour for a detached home.

Solar Heat Gain and Glare: Often, even in winter, if the sun is beating down on a house, without the protection trees or other buildings, the area under the skylight within the house will become so hot or bright that you avoid it completely. This effect is particularly brutal in the summer and will have the added consequence of forcing your air conditioner to work overtime. In fact, solar heat gain and direct glare from poorly placed skylights can negate any natural daylight advantage there is to installing them in the first place. Nels mentioned that with respect to solar heat gain, in the latest VELUX skylights, there is three times less solar heat gain than there was even ten years ago.  Further, VELUX is developing an exterior awning system to prevent solar heat gain and help block glare even more. As it is, you can add an interior blind system, operated by remote control, this is particularly relevant in a bedroom if you don’t like waking up with the summer sun (in Montreal in June, dawn starts around 4:30am and sunrise is at 5am). In fact the addition of a light-blocking blind to a skylight can increase energy performance by as much as 45%.

As the technology of skylights continuously improves, skylights’ importance  in a home’s design and functioning becomes increasingly valuable and homes built to Active House standards take full advantage of the newest skylights’ multi-functional qualities.

The multi-functional skylight:  The Thorold house is designed with 14 skylights which are used to bring daylight into areas that might not receive it otherwise such as bathrooms and stairwells. With increased daylight, demand for electric lighting is significantly decreased versus a standard house.

The ability of VELUX skylights to open to let in fresh air and let interior hot air escape allows architects who promote natural over mechanical ventilation to make use of stairwells as heat stacks.  When the cooler night air advances, ground floor windows can be opened along with skylights. As the hot air escapes through the skylights, the cooler night air gets sucked into the house to replace it. Cooling down a house is much more rapid, easing pressure on air conditioning and the electrical load.  Further, VELUX has just incorporated a solar panel into its skylight to operate it, so there is no need to add to the electrical load.

Rain Sensor: Because the skylights are operable, they include a rain sensor so if you aren’t home and it rains, they will close automatically.

Effectively placed and properly installed skylights can be a positive addition to any building, providing natural daylight in hard to reach spaces, lowering electrical lighting loads and improving occupants’ overall well being.

To find a Velux dealer near you visit the Velux website.

 

The Active House Philosophy – A New Building Standard From Europe

January 23rd, 2014

You may already be familiar with the Passive House movement. Homes built to that standard are entirely concerned with energy consumption from heating, cooling and plug load. The standard requires that homes be so well insulated that there is no need for a conventional furnace, but rather a pellet stove, baseboard heating or a heat pump will do. Because the standard focuses entirely on heating, builders attempting passive house certification will also sometimes combine it with other environmental certifications, such as LEED, which is concerned with overall building and occupant health. Now, however, there is a new building philosophy called Active House that was developed by several representatives, among others, those from Denmark and Holland. It has three main tenets: Occupants’ indoor comfort be maximized, Energy Consumption minimized and Environmental Conservation be considered at each building phase from design through use through end-of-life.

Active House Web of Categories

Instead of evaluating homes on a “points” basis the way LEED does, Active Houses are evaluated in a web on a scale from 1 to 4. “1” being the best and “4” the lowest. The idea is to achieve as many of the specific category demands as possible to create a broad web – 1s and 2s, the outer rings of the web, being preferable to 3s and 4s, the inner rings.

Comfort: The first category considered is indoor comfort. This is a broad and somewhat open-ended term and covers daylight, indoor temperature and indoor air quality.

  • Thermal Environment: One occupant might be more interested in keeping a room warmer or cooler than another and that’s exactly what the creators of the Active House had in mind — individual desires of the occupants. To achieve this and to conserve energy, zoned heating and cooling are used for different floors and rooms. Further, through the use of low to no energy features including orientation of the building, heat stack design, operable windows and the maximizing cross breezes, the use of natural ventilation is optimized and mechanical ventilation (and therefore electricity consumption) is limited. Building envelopes are well-insulated, so the addition of a Heat Recovery Ventilator is usually necessary to allow fresh air to enter and moist, stale air to leave the building even on excessively cold or hot days when windows aren’t opened. HRVs also improve energy efficiency as they transfer the heat from the stale air leaving to the fresh air entering.
  • Daylight: Of critical importance to a person’s mental and physical well-being is the amount and quality of daylight a building is designed to receive. With the fairly recent discovery of Seasonal Affective Disorder (SAD), most of us living in the Northern Hemisphere don’t receive enough natural daylight during the winter months, one of the consequences for some people being depression. Architects working to Active House philosophy are required to design homes with high quality daylight reaching as many lived-in rooms as possible (storage and utility rooms aren’t counted). The recommended daylight factor is 2% or higher, while the lowest score of evaluated rooms must be greater than 1% on average.
  • Indoor Air Quality: The Active House standard requires a constant supply of fresh air into the building, whether through operable windows or an HRV or a combination of the two. The HRV also can be used to control indoor humidity levels ensuring a dry environment to prevent mould growth.

Energy: Since the operation of buildings worldwide consumes about 40% of all fossil fuels, an Active House aims to be light on the use of carbon-based fuels and nuclear energy. For example, a house that uses 100% renewable energy scores a “1”, while a house using 25% or more renewable energy would score a “4”.

  • Energy Demand:  This is the amount of energy required by the house, including space heating and cooling, water heating, lighting, ventilation, technical installations, plug load and appliances.  In the design phase, architects will focus on designing a house that maximizes energy conservation and efficiency by taking advantage of passive solar gains for both lighting and heat, as well as designing tight building envelopes. Other features include the addition of renewable energy systems and demand-control ventilation, which also contribute to the energy savings. Use of dynamic building envelope with solar shadings and natural ventilations reduces the need for
    mechanical cooling and air conditioning during summer period. Finally, the type of construction is very important to successful implementation of this phase.
  • Energy Supply: The type and quality of energy supplied to the house is another important facet of the Active House philosophy. Homes that use 100% renewable energy produced on site or nearby receive a “1”. Homes that use 25% or more renewable energy receive a “4”. Note that not using any renewable energy isn’t even an option, regardless of how efficient you are.
  • Primary Energy Performance: This value is the calculation of (total energy consumption – renewable energy supply) x national primary energy factors. What they are looking for here,, in principle, is your CO2 output based on the national, or in our case, provincial, energy production mix. If your home uses 100% renewable energy, either from the grid or produced all on-site your score would be “1”.

Environment: This is the area that focuses on building materials, waste and life cycle. The Active House is concerned not only with the functioning of the building, but how it got there and what will happen to it when its useful life is over.

  • Environmental Load: Building a house is a disruptive process to the global environment. The Active House takes into account how damaging construction can be by considering a house’s  Global Warming Potential, Primary Energy consumption, ozone depletion, smog potential, water acidification potential and eutrophication of the soil. The environmental load is all encompassing, and considers the whole Life Cycle, including the production and transportation of the materials used to build the house, the maintenance and operation of the house, and disposal of the house at end of life.
  • Fresh water consumption: Minimizing consumption of freshwater by occupants’ also plays an important role in the Active House. A “1” is achieved by reducing water consumption by 50% versus the national average, while a “4” is graded for a house that conserves 10% or more. Devices and techniques used can be items such as a cistern to catch rain water or a gray water system, which captures used water from baths and showers and recirculates it to toilets. Low-flow fixtures can also be installed.
  • Sustainable Construction: As many renewable and recycled/recyclable products are used in the construction of the house as possible. A house containing a minimum of 5% recyclable content will receive a “4” while a house that uses over 50% recycled content receives a 1. Regarding wood, the standard is more demanding. At least 50% of all wood used in construction of the house must be certified either by PEFC or FSC. 25-80% of new material needs to be EMS certified. If you’re not familiar with this requirement, EMS stands for Environmental Management System, usually referring to ISO 14001 standard which is a voluntary guideline outlining the criteria a company would have to go through to get ISO 14001 certification. A company with an EMS in place tends to have a greater responsibility with how its products are made, including taking steps towards responsible sourcing and improving its overall energy and water efficiency.

Qualitative parameters:  In addition to the evaluative web used to rate an Active House, there is a long list of other considerations that are used to make this house a lower impact, thoughtfully designed house, which architects, designers and other building professionals can use as a guide. Other issues such as noise and acoustics, accessibility, visual transmittance and glare management among the factors considered.

The philosophy behind the design process is thorough, thoughtful and addresses gaps in the Passive House built house and even the LEED for Homes designation. It does not go as far as Living Building Challenge, which requires that most, if not all energy and water used by the house be produced or captured by the house. Perhaps though, it is a more realistic approach for urban dwellers. The developers of the Active House philosophy consider it a work in progress, not dissimilar to LEED. They evaluate houses already built to the standard to see how it can be improved. Homes are evaluated before and during occupancy and compared so that professionals involved in Active House design-build can learn from the results.

Active House Principle The first Canadian built Active House has just been completed in Thorold, Ontario by Great Gulf Homes. It provides an excellent example of the philosophy being put into practice. Stay tuned as I will discuss the features of that house in the next post.

For more information on the Active House philosophy, visit the website: http://www.activehouse.info/

The Active House Alliance is now in process of developing concept guidelines and classification for Active House projects, with an expected launch by the end of the year.

For two Active homes already built, see the following articles:

First Active House Nears Completion in the US

 

La Maison Aire et Lumiere (in French)

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