The design process for a high performance home in the forests of Southern Vermont
We are starting a new Bluetime Collaborative project here in the Brattleboro area. This will be a High Performance house that will provide the chosen team including myself and the builder the opportunity to refine the integrated process that goes with building a HPH. We don’t know yet if this project will be built toward any certification such as Passive House or Efficiency Vermont’s High Performance Home program. That question will be addressed early on in the design process. I reworked my contract quite a bit to set up and guide the process better than a standard contract does. This includes fleshing out the design process, what to expect and when, expected meetings along with the purpose and goals of those meetings and finally, guidance with selecting the right contractor for the job at the start of the project – meaning at the start of design.
I am fortunate to live and practice in an area with an impressively large number of excellent builders with a high level of interest and enthusiasm for building science and green building and training in Passive House and high performance building. I have been finding that I can’t or rather, shouldn't, as an architect, design and detail a HPH without the full partnership of the people who will be doing the actual building. I can’t draw up a set of plans and send them out to bid. There are many conversations to have during the design process with the builder and a high level of builder competency and knowledge is required.
The process of designing and building a High Performance Home requires a level of integration between architect and builder that is uncommon. In the past I have followed a more traditional approach, working with the client to develop a design then taking it to one or more builders to price and build. This is the normal way things are done and many builders and architects prefer this approach. I have decided however that to provide the level of service and quality of product that I want to be known for, a truly integrated and refined process where the builder is retained at the very beginning, provides expertise, guidance, cost-benefit analysis + research support from the very beginning of design is necessary. And I provide similar through construction.
The result can be much more time and resource efficient process, a more refined and well designed project, and overall, a higher level of control and accountability for the builder, the architect and most importantly, the client.
For this project, I introduced my clients to three such general contracting firms and helped them interview all three. The first meeting was with Josh and Gero of Mindel and Morse Builders – a firm that have worked a lot with. I was a carpenter with them in the late nineties after architecture school. The second meeting was almost immediately after that with Scott and Gabe of Mathes/Hulme. I had done the Brattleboro Tiny house with them several years ago when they were just getting started on their own and we have been looking for a project to do together ever since. Later in the day we met with Chad of Vermont Natural Homes (who built the Greenfield house) at his own straw bale home complete with an amazing spread of hors de vors (thanks Carly!) Wish I had gotten a pic of that.
All three firms are super-professional and very supportive of each other. There is an impressive culture of support among many local builders locally with a monthly building science group that supports continuing education and discussion. Firms often help each other out with manpower and expertise. This project can provide an excellent case study and learning opportunity for the local building community.
Over the next week, the clients were further wined and dined by the builders with house tours and the clients were starting to realize not only that they were in good hands but that they had a really difficult decision to make in choosing which builder to hire.
So now that I have put some serious pressure on myself (and the builder) to do an awesome job, I will reveal that the clients have chosen Mathes/Hulme who are now busy writing up a pre-construction agreement which will be a further definition of their role in the process that I introduced in my own proposal. I haven’t had a conversation with the clients yet about what tipped the scales toward Mathes Hulme. I tried to remain very neutral during the interviews which was rather easy as I was just pleased with the opportunity to work with any of the firms.
I will be meeting this week with Gabe Hulme and Mel Baiser of Helm Construction Solutions, a construction management firm that both Mathes/Hulme and Vermont Natural Homes use. We will discuss first steps, who will be doing what and when – process and scheduling. We will discuss how communications will be handled (we might give Slack a try) and generally mapping out the next few months. I have been sketching - schemes, sections, details etc to start that conversation with the builder before I refine it a bit and present to the client.
Here are some decent shots of the Greenfield House project which is nearly complete and not a full-on Passive house but did meet the Mass Tier 3 rating requirements. There will be minor things to do over the next year. I will continue to photograph this house over time to improve my photography skills so stay tuned for more. This project was a collaboration with myself, Vermont Architect Robert Swinburne, sometimes known as Bluetime Collaborative and Vermont Natural Homes and Helm Construction Solutions working for VNH Details: The house has 16" thick walls with an empty service cavity so that's not all insulation, Klearwall windows + a Menk storefront window, custom fabricated steel stairs with live edge cherry treads, local maple floors, Vermont slate tile in the upstairs bath and mudroom, stone countertops from Ashfield stone - (the stone is quarried locally and represents the underlying bedrock in this region) - accurately detailed and proportioned roof trim (to make the house look super classy) a bold front porch made from Vermont white cedar, black three tab shingles ( I HATE architectural shingles). We achieved an airtightness level of .066 - Mike Duclos of DEAP Energy Group did the testing and Mass Tier III certification. Fresh air is supplied by two pair of Lunos through the wall air exchange units from 475 High Performance Building Supply The overall footprint is 700 s.f. with 600 s.f. per floor on the inside. Visitors report that it feels much larger.
The overall design is intended to be super classy and appeal to both traditionalists and modernists without being overtly stylistically categorizable. I wanted to show that a modern, superinsulated (almost Passive House certifiable) house doesn't have to look super modern or look like it was designed by an person who only cared about the numbers like so many super high performance houses do. I think we pulled that one off.
I have a lot of photos from the Greenfield project. I am spending a fair amount of time on site working out details with the builder. I strongly feel that this is the way it should be. Things never translate perfectly from paper to built form no matter how much detail and specificity I put into a set of construction documents and on this project, I am spending much time on site figuring things out and detailing to a higher level. I think Chad, the builder, appreciates this process and I'm finding that it hearkens back to my pre-architect design build days. I hope to do more projects with this level of involvement in the future. I really think that this is "the way to go" here are lots of photos. Note the local wood use: Cherry stair treads with "live" edge, local maple flooring downstairs and pine upstairs, Vermont slate, and a wall sheathed with weathered pine off my own land.
Bob, in response to your invitation to comment on the passive house you are designing for us, here are some thoughts. I see this first of all as an opportunity to be part of the solution instead of part of the problem. The chance to show off the kind of technology and design choices that--were they widely adopted--could significantly reduce reliance on fossil fuels feels not just like an opportunity to showcase your talents as an architect but to participate in a necessary new way of thinking about housing. That you are, coincidentally, our son-in-law certainly plays a role in our enthusiasm, but it goes so far beyond providing for immediate family and grandchildren. It goes to realizing the models that are going to keep the earth inhabitable for everyone's grandchildren.
Coming back to the ground now, to the very immediate house in question and the very personal responses on an aesthetic and emotional level: It's exciting to think about having a space designed to support who we are and how we like to occupy space. The openness of most of the design, combined with the privacy of spaces designated for bedroom and in-home offices for each of us, is perfect. I imagine fondly the day when, if one of us is cooking in the kitchen and the other is in the living room, we won't have to shout to each other to be heard. I look forward to having a cup of tea by the floor-to-ceiling south-facing windows. Visual access to the outside year-round is crucial to my mental health, and if I have a view of the outside space, I need far less inside space. I am inordinately pleased by the idea that we may be able to design a root cellar into this house. The idea of storing garden vegetables connects the seasons for me. (An aside: I got a ridiculous amount of pleasure in Seattle from picking kiwi fruit in October/November, and eating it in December, January, and even February.) And, of course, those floor-to-ceiling south-facing windows will be a great spot for starting plants in the winter and early spring. Did I say I love the idea of floor-to-ceiling south-facing windows?
We love wood fires, but I've got to admit that each time I build one these days and notice the ash that has to be cleaned out and the wood dust on the rug that will need to be vacuumed I realize these are tasks I will not miss. And again, as we age, and things tend to take a little more time to accomplish just because of increased physical limitations, I won't regret leaving wood and ash hauling behind. It will leave more time for reading and writing. In the cozy office spaces or by the wonderful floor-to-ceiling windows.
Then there’s air quality and noise issues. I’m given to respiratory irritations and ailments, which means that, especially during heating season, I keep a HEPA filter running in the living room and a humidifier in the bedroom. Both are noisy, but help to create a white noise effect that drowns out traffic on the street outside. I know I’m going to enjoy the quiet of a super-insulated house and the climate-controlled clean air I’ll be breathing.
As we are very near retirement age, it pleases me that we're designing this house to be one in which we can age. Thinking ahead not to the inevitability but the possibility of one or the other of us needing a wheelchair at some point, and having the first floor bathroom at the ready, means not having to worry about retrofitting in a hurry someday.
Just knowing some of the principles of Passive House design has made me so much more aware of heat and cold. I take a hot bath, and imagine the system that will capture the heat as the water cools. I open the curtains when the sun is shining, the better to capture a bit of the free solar warmth. I have begun to use the term "thermal bridging" in casual conversation.
Circling back to the overview: I like that we are able to support, with this project, not only the concept of Passive House but also the business model that you, Mel, and Chad are using. Having presided over a remodel in Seattle, I need no convincing that it's going to be worth it to have project coordination and scheduling built in to the process and the services your team is going to provide us.
This is from Mel Baiser of Baiser Construction Management. I am working with her on several projects and here is what she has to say about the Greenfield project. I have the great fortune of teaming up with Architect Bob Swinburne of Bluetime Collaborative and builder, Chad Mathrani of Vermont Natural Homes on the construction of a Passive House in Greenfield, MA. This project is incredibly exciting for a number of reasons. For a passive house certified builder (PHIUS) this is rare opportunity to be involved in the planning and construction of a home which meets the highest international building standards. As someone in my mid-thirties and the parent of a young child, I am all too aware of the climate crisis. I am also a firm believer in that bumper sticker slogan, “If you are not part of the solution, you are part of the problem.” Having dedicated over a decade to working in construction, I am committed to every effort to push this industry towards sustainability. After all, nearly 50% of the energy consumed in the U.S. can be attributed to the initial construction and operation of our buildings. Buildings that meet the Passive House standard are the buildings of tomorrow (even though we are far behind Europe and really they should be the buildings of today.) My company’s logo is “revolutionizing the building process” and though I may be outing myself in terms of political sympathies, my intent is to bring a new level of efficiency, organization and collaboration to the construction industry. In particular, in a high performance, net zero or passive house building, effective pre-construction planning and an integrated delivery process is essential to the success of these projects. My company offers cost planning, scheduling and project management services and I feel grateful to have found like-minded architects and builders (and clients) with whom to collaborate. I often find the traditional top down, architect driven delivery method (design, bid, build) to be antiquated, inefficient and not a suitable match for high performance building. By involving the builder, cost estimator and even the client very early on in schematic design, you can save thousands of dollars, weeks in the schedule, avoid technical errors and potential interpersonal conflict down the road. Green building is really nothing more than a marketing tool until we make it financially and culturally accessible. Aside from achieving the Passive House standard (heating and cooling demand less than or equal to 4.75 KBtus per SF/Yr; Primary energy demand less than or equal to 38 KBtus per SF/Yr and an air leakage rate of .6 air changes per hour at 50 Pascal) our team is motivated to bring this project in on a relatively modest budget. An architect committed to building performance, budget, function and aesthetic; a contractor/project management collaborative leading local natural and high performance building efforts and a client who believes in the importance of healthy efficient homes and “you get what you pay for” is the absolute dream team for any project, but especially for this project.
Mel Baiser Baiser Construction Management email@example.com
I took a shot at writing down my own thoughts about the Greenfield project I’m doing for my wife’s folks. Sometimes I have so many half-baked ideas in my head that writing them down creates a jelling effect and helps me to clarify and focus my efforts. I’m planning on documenting this project to a much higher level than I have in the past, partly because we are assembling something of a dream team to get this done and partly because I am using this project to redefine how I work in order to bring my own practice to a higher level. I have encouraged the others to start writing as well and some of that will show up here on the blog as well for a more well-rounded perspective. We are currently exploring the feasibility of doing this house as a Passive house and seeking certification. I hope, as usual, to show what can be accomplished when a highly functional and customized plan is also an emotionally uplifting place to live. This projects continues my exploration into the emotional aspects of “home” and how to use architecture to augment and reinforce the emotional connection to place. Phew! What have I to gain from doing this project as a full-on Certified Passive House? So what if the winter heating bills drop from $75/month to $25/month? Is that really worth all the extra effort and expense to go through certification? We don’t know the answer to that yet. “Let me run some numbers” as the engineer or accountant would say. Passive house has cache. It attracts media. There is huge marketing potential. The clients (my in-laws) are understandably interested in that aspect of it - it relates to their son-in-law’s ability to financially support his wife and children. I want to do more of this type of work in the future and will I ever get such a good opportunity to gain exposure, attention and build a reputation that to do a very attractive and relevant project at this highest level… and market it to the greatest extent possible. I have seen that model propel other firms into the limelight so I am aware of what power and potential in inherent in this thinking. Otherwise- My own limited knowledge of Passive House indicated that this house as designed thus far could attain Passive House certification with minimal extra effort. I’m a Certified Passive House Designer – CPHD with the international credential but I have little practical experience. This project could be a great way to gain that experience. The most effort and extra money will probably be in soft costs – hiring someone with experience to do the energy modeling, advise on detailing and assist in the certification process. With this project we are also formalizing a fairly progressive project delivery process that I am realizing is crucial to creating high performance buildings. This represents the direction my own business model is headed in. I have, in the past, followed both the more traditional architect route where I work with clients to design and detail a project and we shop it out to builders. I have also worked (more often) in a more design-build model where the builder is integrated into the process from very early in the process. That has been my preferred method of project delivery but I am realizing that to provide the highest levels of service, I need to fill in some gaps. I can’t do everything and I don’t have expertise in everything so I’m bringing in people to help fill the traditional gaps. Subcontractors as well need to be on board as part of the team at a much earlier stage and need to be aware that they will be asked to perform at a very high level of professionalism. Part of my job is to make that as easy as possible for them through design and detailing. I am working on this project with Mel Baiser of Baiser Construction Management and Chad Mathrani of Vermont Natural Homes both of whom have training in passive house detailing and construction. They understand what it takes to reach that highest level of building excellence. And considerable enthusiasm to do so. We are pouring over the details as fast as I can draw them up to insure that no stone is left unturned. The process requires a high level of integration at this early stage in terms of product selection, integrated assembly, cost (and relative costs). Assumptions are challenged and vetted and everything will be put down on paper before the project is staked out on the site which is under considerable snow at the moment. We will maintain a process blog as part of Vermont Architect to provide a window into this process. Blog readers and Bluetime Collaborative facebook followers have already seen some early schematic design images of this project. Stay tuned.
I’m working on detailing out a smallish house in Greenfield, MA. We probably won’t go full Passive House on this but we will look at what additional costs and detailing it would take. And if we’re close… We are doing some novel (to me) stuff for the shell of the house that, I suspect, will become more standard practice for me in years to come. Here are some “progress print” detail drawings from the plan set. My drawings tend to look a bit different than most architect's drawings due to two things: The time I spent wielding a hammer and trying to interpret my own drawings and the fact that I have worked as a sole practitioner for so long and have developed my own graphic style. I should add to that a third thing – my knowledge of building science informed best practices.
The first thing you will notice about these drawings is actually the most important thing. The red and blue dotted lines represent the weather resistant barrier and the air barrier respectively. If your drawings don’t have at least the air barrier called out in the sections, (and continuous around the thermal envelope) The drawings are incomplete. I have been getting picky in my detailing about how to make the air barrier both easy to achieve and durable. In my opinion, relying on painted sheetrock to serve as an air barrier just doesn’t cut it – certainly not for the next 100 years.
Many builders and architects in the Northeast US are still building 2x6 walls with fiberglass batts and a poly vapor barrier. That’s how I learned to do it when I was just starting out in the 90’s. I also opened up a number of walls built that way that were full of mold.
builders don’t build this way anymore. Check the Building Science Corporation website for some pictures of what can go wrong.
One part of building science is probability and statistics. I often hear builders say “I’ve always built that way and I’ve never had any problems” - that you know about. But those builders are only looking at 50 or 100 projects. Luck plays a part here. What happens when you look at thousands or even tens of thousands? You start to see some patterns emerge and you start to see the luck factor drop out of the equation. You are able to formulate some best practice standards for a number of things including durability, air quality, energy use and even catastrophic failure. I prefer to work with builders who are informed about building science and involved in the discussion.
That’s easy here in the Southeastern Vermont area home of Building Green area, home of Building Green and SEON which sponsors a well-attended monthly building science discussion group and learning circle. – If anyone wants to get something like this started in their own community, send Guy an email at the address in their website.
I owe it to my clients to help them get the best constructed project possible. That, in addition to the most functional, aesthetically appropriate, finely crafted project possible. – Oh and the budget thing too – Detailing such as represented in these drawings is also very much about budget. The goal is to bump up the levels of insulation, air tightness, r value of windows etc. so that we can eliminate the traditional boiler and heat distribution system in favor of a minisplit heat pump which is more of an appliance than a system and dramatically less expensive. (I think this link is a GBA pro only link - subscription) For those without a subscription try this alternative Ideally, it becomes a wash cost wise but with the added bonus of very low monthly heating and cooling costs. Those savings alone can represent hundreds of dollars per month.
I am working on a 1400 s.f house in Massachusetts. Given that the walls are over a foot thick, the actual square footage is quite a bit less (about 1200). The extra insulation (and cutting edge building science) allows us to forgo a heat system other than a relatively inexpensive minisplit - and monthly fuel bills. Here are a few images of what I'm up to. no fancy rendering for now, just the Sketchup model and some Vectorworks CAD drawings.
I spent a fair amount of time detailing the steel and wood stairs in Sketchup as I have found that is the only way for me to really figure out every nut and bolt and refine the design to the level that I am comfortable with before construction drawings. I like to approach the stair as sculpture with every piece exact and connections "just so". Thus I am able to design something that is quick and easy to assemble with just the right amount of "fudge space" built in.
The floor plans have shrunk and simplified from the last version becoming more functional and comfortable.
Just a quickie about thermal bridging and air sealing. I can explain it in way fewer words and terms and scientific-ness than what you find when you go looking for information on the web. Thermal bridging is when there is too much stuff that is not insulation in a section of exterior wall. This includes most traditionally framed houses. Especially near outside corners and around windows. In the cold of winter, the inside room surface of these areas stay much cooler than the surrounding room temperature and condensation occurs, then mold.
Improper air sealing is when your builder tells you your house needs to breathe and he's not talking about an air exchange system. Improper air sealing allows air to enter your house through tiny pathways through and near these moldy areas. The mold spores are then breathed in by your children.
A House for Slow LivingThe original concept came to me in a dream (yes – I dream architecturally) I think the dream may have been generated by this image which has been on my bulletin board fora few years: The original sketch was called “a house for food”
The core concept was centered around the growing, preparation and consumption of food which lends itself to the idea of gatherings of family and friends and leads to the notion of how to live in a close relationship to the local environment. From my own experience I drew upon the old fashioned ideas of hunkering down by the fire on a cold winter evening, opening the house up to the sounds, smells and breezes of a summer day, “putting food by” and making routine preparations for winter in the Autumn, starting seedlings on a windowsill in the spring, caring for children or elders. Also, how can we appreciate the beauty of the winter landscape and light without feeling overcome by it. This is a common issue in the Northeast. Where do you sit to watch a thunderstorm rolling in or to watch the snow fall? Music! – not just acoustics but around here, everybody is also a musician. How does that fit into our daily lives? Much inspiration is to be found in images and stories depicting rural life from previous times in Europe and America. I am drawn to the imagery of hard working English country houses where the real life of the house centers between the kitchen and the door stoop leading directly to the working yard and gardens. Think: Peter Rabbit in Mr. McGregor’s Garden by Beatrix Potter with a potting shed, cold frames and lots of cabbages. I am fascinated by early New England farms and town dwellings and how lives were played out in them. Not the big events but the little, day to day, season to season routines. Light and fresh air are celebrated and sought after and even, perhaps, taken for granted in an age before television and telephones. Materials are worn but durable, practical and show their age and history and that is where their beauty lies.
The Building Science aspect of design and detailing that we are all so immersed in lately addresses the idea of being able to lock the door and walk away for a month in the winter and not worry about much of anything. The neighbor has the key and will water the plants. Building Science addresses being what we are calling “net zero” so you are not storing and burning fossil fuel on site and paying for it as well. Building Science addresses the notion of simplicity – who needs a heating system that could go on the fritz and bust your pipes and freeze all your house plants so when your neighbor comes over to water the house plants, he finds an awful mess and has to call you in some recently devastated country where you are doing relief work. Building Science allows you to return in March to a house filled with fresh air and no mildew. (building science can’t help with what you left in the fridge) Building Science can free you from many previously taken for granted maintenance issues and expenses such as painting and periodic repair, maintenance and replacement of the mechanical parts of the house because now you have fewer and simpler systems.
How then, to marry my heady and romantic thoughts with the physics of modern building science? How do I pack all of this sensuality and feeling into a house that celebrates the process of living this chosen life rather than reminding one of the potentially inherent drudgery? Since these ideas are very personal to me, it isn’t very difficult to make a series of design moves and decisions that bring me pretty close. I have been moving in this direction for much of my life. I am often “pretty close” but getting to that higher level is tricky and elusive. I’m not there yet with this design but it’s still early….
In this design, I'm trying to balance small and simple with a richness of space that goes far beyond light and shadow, a good floor plan and simplicity of form and add my own interpretation of what it can mean to live in Vermont and lead a life integrated with the climate and culture of the place. I'm drawing heavily on history and my own sense of aesthetics as well as all my cumulative observations and experience.
Dang! Maybe I should tear down my own house and build something like this!
Note: this blog entry was published on Green Building Advisor on March 31, 2014 I have been asked about my Passive House consultant training by other architects enough times that I though I'd write up a quick synopsis, one year later.
For me, the Passive House training was very useful for several reasons, not the least of which was the networking aspect. It is a small community with some really great conversation happening and it is fun to be a part of that. There is a lot of controversy as well, especially on GreenBuildingAdvisor.com Such as where does the law of diminishing returns kick in when it comes to insulating and how to handle latent loads (excess moisture). Plus there's the whole U.S. vs the rest of the world thing which I won't go into as I find it rather annoying, or at least boring. Secondly, It represents state of the art science on how to build good buildings with an overriding emphasis on simplicity and quality. Passive House is really all about quality and even, as I'm finding out, represents a necessary re-thinking of how to get something built. A much more collaborative approach is necessary than often happens when building even high-end projects. The process gets much less linear. I also like the idea that the Passive House approach is a valid part of the conversation, not just achieving certification and getting the plaque to hang beside the front door. I see projects being showcased that utilized the approach in a value engineering manner to get the most bang for the buck that simply don't have the budget to go all the way and attain certification and I like the general consensus that that is okay. Much of my own work had been trending in the PH direction anyway so it was good to undergo the intensive training so that I could make decisions with much more confidence and authority that comes with PH credentials. As an architect who was never very (ahem) enthusiastic about the numbers and physics of things and more into the airy-fairy poetic nature and scholarly aspect of architecture it was also helpful in terms of training my weaknesses. I call myself a Passive House designer rather than a consultant in part because If I were to attempt a full-on certified Passive House, I would want to hire someone more experienced who does this on a daily basis to do the actual numbers part and look over their shoulder through the process - at least for the first few times. There is also the notion, similar to my approach to structural engineering where I try not to design anything too complicated to engineer myself - I prefer not to design anything that would require a complicated heating/ventilating system. It does get more complicated in renovation/addition work though for sure. My approach to structural engineering has always been very intuitive and very related to my own building experience and knowledge of materials, assemblies and connections My structural engineering professor once told me that the intuition part is vital and more than half the battle. First you intuit the solution then you apply numbers and formulas to check yourself. The Passive House training augmented my intuition and gave me more confidence to apply the numbers as well as a perspective on when, where and why.
Plus it was really good for marketing.
I had another comment recently from a builder who wants to build a house that breathes. I started to reply in an email and then decided to put it hereon the blog instead. What we are doing nowadays in the world of high performance homes is based on studying hundreds of thousands of houses built in the last half century that have failed (which includes the majority of 70's and 80's super-insulated and passive solar homes in the northeast) and applying those lessons to building a durable house nowadays. Houses from before that time period that failed for one reason or another are mostly gone and many of those that remain are simple piggy banks for big oil. We put our money in and the oil companies take it out. Simple. (usually, I like simple but...) For the past few decades, builders in the northeast have been living in a vacuum while the northern Europeans and Canadians paid much more attention to how houses fail, learning from them and adapting. Now the conversation is opening up again and we are taking a seat at the table.
I have lived in houses that breath my whole life. It sucks. Aside from the part where you have to give your money to someone else just to not freeze to death in the winter, there is the comfort aspect of things. Houses I have lived in have never been all that comfortable whether in terms of temperature or moisture levels or even wiping mildew off the window sills. Now, with two children, I worry about the air quality and mold issues inherent in my house that breathes. I would rather be able to seal up the house in the winter and be confident that I was breathing fresh Vermont air all the time than have to step outside for a breath of fresh air or open up the doors and windows if I screw up on getting the woodstove going. Six months out of the year, I would still have the choice to open the windows and turn off the HRV.
We do seem to have more summer moisture and humidity problems than we used to but we also have access to more durable and proven materials and building methods. Some builders and architects are taking advantage of this but most are building the same way they did 20 years ago despite all the failures. A house that breathes and has little or no insulation is a barn and If you want to heat it, that means coming to terms with giving your money away. Jesse Thompson says "People breath air through their lungs, not their skin. Why should houses be any different?" If you want your house to breathe, give it a set of lungs.
There are a range of options for doing this from exhaust only bathroom fans and range hoods (simple and cheap but where does the makeup air come from in a very tight house?) to a full-on Heat Recovery Ventilation System or HRV. These are also fairly simple and effective although significantly more expensive but have the added advantages of recovering much of the heat from the outgoing air as well as providing fresh incoming air exactly where you want it. For more information just type "HRV" or "house ventilation" into the search box on Green Building Advisor and start reading.
Designing a Super-insulated wall with good drying potential and good air sealing is easy. But the Devil is in the windows. With passive house level construction we want the window to be recessed toward the middle of the opening and the middle of the adjacent insulation layer. This is about thermal bridging and heat loss. An advantage that I've found is that it can potentially simplify the flashing which is certainly a welcome idea. Window and door installation has become increasingly complex over the past decade especially with exterior foam details. (I try to stay away from that) What I'm looking at in this sketch is how flashing for siding can be decoupled from flashing for the window to a great extent. Does the siding even need flashing anymore? Depends on how you do the siding. With some Rain screen siding details, perhaps not! Windows are now coming with really nice integrated sill flashing - you specify the depth when you order. This makes for a much more integrated and seamless system which should have long term durability advantages over what we have been doing up until now. What is missing from this drawing is an exterior layer of rock wool insulation to keep the sheathing warm (not rigid foam !) A more expensive detail and this may be less important when using cellulose than fiberglass insulation but is a detail I would certainly do on my own home. The other option is to use more of a Larsen truss system similar to what Chris Corson is doing in Maine with no exterior sheathing. It is A tough sell around here to leave the insulation protected only by a weather barrier such as Mento plus. The conversation on building science is terribly interesting and seems to be resolving itself towards simplicity as we gain knowledge and experience about what works and what doesn't and develop products and materials based on our increasing knowledge base. Of course, 93% of builders and architects aren't really paying much attention.
Sort ofThis is a schematic design for a local project I'm working on where I am doing master planning up front. See this post. After meeting with Gary MaCarthur to look at the whole site and master plan in terms of solar potential - the owners may, at least initially be "off the grid" - it was clear that the best locations for the house and barn were not so great for photovoltaics. Gary, like many other folks who design and install PV, like a clean simple installation, Ideally on the steeply pitched roof of a shed where the equipment can be housed. "a Power House". I knew the owners wanted to be able to spend weekends on the site year round and be comfortable and we had discussed building the barn first and finishing off the upstairs. Not a great solution unless you are prepared to build a fairly expensive barn as opposed to a pole barn for equipment and animals. Gary, upon listening to the master plan, long term build-out goals, suggested a cottage instead which could eventually become a guest house but in the meantime would serve as compact living quarters, the power house and storage for a tractor and whatever things get left here on a more permanent basis initially. being relatively small, a cottage could fit nicely into the overall site plan in a location ideal for photovoltaic panels.
As usual lately, I'm trying for the holy grail on this one and I hope the clients like the ideas. Holy Grail = Competitive cost Passive house priciples of low energy use, durable design and good building science local materials wherever possible and minimal environmental impact of materials Logical construction methods – nothing complicated or fancy Simple modern design – Scandinavian-ish? Clues from tradition but not a slave to it. - No Anachronism - use what works and eliminate frippery Texture and light and air Shadow and light. Intimately tied to the land. Seasonally adaptive and responsive Low maintenance – no or minimal exterior paint, stain , varnish – weathering materials and durable materials Emotionally uplifting space Proportion and grace.
Specifically to this project the long design seems to work best in terms of what we want to do with the site, the available roof for solar, the idea of layering, keeping the roof sheltering and low at the eave, build part now/part later if needed to get power set up, the gardeners cottage / gatehouse idea, overall simplicity, steep roof (Gary says to max winter gains) etc. I was also looking at cladding materials in more of a fabric sense with varying degrees of transparency which seems very Japanese and works very well for how I design wall systems.
Here is the initial sketch from my sketchbook:
What is Passive House ?
- The passive house standard represents the highest level of energy efficiency and “green building”. - The passive house standard is where state and municipality energy codes are headed. - Public housing groups such as Habitat for Humanity and regional housing authorities and land trusts are starting to require new housing units to be built to the passive house standard as these groups tend to prioritize overall cost of ownership over initial cost of construction. - The roots of Passive House trace back to the 1970s, when the concepts of superinsulation and passive solar management techniques were developed in the United States and Canada. - More than 25,000 buildings have been built to the Passive House standard in Europe. The standard is especially common in multi-family housing where it often makes little financial sense not to build to this level of energy efficiency.
Concept “Maximize your gains, minimize your losses”. These are the basic tenets of the Passive House approach. A Passive House project maximizes the energy efficiency of the basic building components inherent in all buildings; roof, walls, windows, floors and the utility systems: electrical, plumbing & mechanical. By minimizing a building's energy losses, the mechanical system is not called to replenish the losses nearly as frequently. This saves resources, operational costs and global warming related pollution. Unlike any other structures, Passive House buildings maintain occupant comfort for more hours of the year without the need for mechanical temperature conditioning of the indoor air. The opposite has been the norm in this country where we have a history of inexpensive fuel and construction techniques with little consideration for energy losses through thermal bridging, air-infiltration, and inadequate levels of insulation.
Passive House is both a building energy performance standard and a set of design and construction principles used to achieve that standard. The Passive House standard is the most stringent building energy standard in the world The Passive House approach focuses on the following:
Strategic Design and Planning: Passive House projects are carefully modeled and evaluated for efficiency at the design stage. Certified Passive House Consultants are trained to use the Passive House Planning Package (PHPP), a tool that allows designers to test “what-if” scenarios before construction begins. They are also trained to use other software tools to identify and address potential thermal bridges and moisture issues at the design stage. Specific Climate, Siting and Sizing: Passive House design uses detailed, specific annual weather data in modeling a structure’s performance. Orientation of the windows can maximize or minimize solar gain and shading. Passive House theory leans towards minimizing the surface area to interior volume ratio, favoring an efficient shape to minimize energy losses. Super-Insulated, Air-Tight Envelope (But Diffusion Open): To keep the heating/cooling in, wall assemblies require greater insulation values to “stop the conditioned air” from leaving. Walls are typically much thicker than today’s standard construction. Passive House takes great care in designing, constructing and testing the envelope for an industry-leading control of air leakage. Blower door testing is a mandatory technique in assuring high performance. Walls are designed to be virtually air tight, while allowing water vapor to dry out. “If moisture gets into the wall, how does it dry out before damage can occur?” is a fundamental tenet of modern building science addressed in Passive House design. Wall assemblies are analyzed to allow for proper water and moisture management to make a long lasting and an exceptionally healthy building. Thermal Bridge-Free Detailing: Breaks in the insulation layer usually caused by structural elements and utility penetrations in the building envelope create a “thermal bridge,” allowing undesirable exterior temperatures to migrate to and “un-do” expensive interior conditioned air and creating colder interior surfaces that encourage the growth of mold. Passive House design attempts to minimize thermal bridges via progressive mindful architectural detailing. Advanced Windows and Doors: Historically these items are the weak link of a building’s envelope and thermal defense system. Passive House places significant emphasis on specifying high performance windows and doors to address concern. To meet the high performance needs of various climate zones, windows must meet strict performance standards regarding: component insulation, air tightness, installation and solar heat gain values. Energy Recovery Ventilation: The “lungs” of a Passive House come from a heat (or energy) recovery ventilator (HRV/ERV). It provides a constant supply of tempered, filtered fresh air 24/7 and saves money by recycling the indoor energy that is typically found in exhaust air. The heat from outgoing stale air is transferred to the unconditioned incoming fresh air, while it is being filtered. It provides a huge upgrade in indoor air quality and consistent comfort, especially for people sensitive to material off-gassing, allergies and other air-borne irritants. HRV's are fast becoming standard equipment in all new houses in Vermont. Heating: One of the best benefits to implementing Passive House design is the high performance shell and extremely low annual energy demand. This allows owners to save on operational costs as they can now significantly downsize a building’s mechanical system. Passive solar gains, plus heat from occupants and appliances supply most of the needed heat. Radiant floor, baseboard, or forced hot air heating systems are unnecessary! Alternative Energy: Considering alternative energy systems on your project? Building to meet the Passive House Standard is the smartest starting point. The significant reduction in energy use, allows alternative energy to power a greater percentage of a buildings demands. Likewise smaller demand equates to smaller and more affordable alternative energy systems providing higher cost-benefit value. Passive House design puts a project within reach for achieving true “Net Zero” performance (the building generates as much energy as it consumes over the course of a year), making use of alternative energy systems smaller thus more affordable and attainable.
From Passive House Academy - I like the use of wine. It takes only two bottles of wine for a family of four.... or something like that. Just watch the video.