Technology Driven Change

Is the future of green building tied to emerging green technologies? Is this what we are waiting for? What will really change? These are questions to ponder as we enter into a new year. And as always, a bit of retrospect offers insight into the path for the future.

The influence of cars and air conditioning on the pattern of American home building is well documented. These new technology made possible explosive growth in Sunbelt cities like Houston, Phoenix, Las Vegas, Atlanta and Miami, where the heat and humidity had been a major comfort issue and a deterrent to population influx. Automobiles also opened up possibilities of living in suburbs, outside of the aging and stinky city centers.

Rediscovering Trolleycars

But this shift did not happen in a vacuum. Market conditions and government assistance has a strong hand in directing the change. In the 1930’s there was an orchestrated effort of the newly emerging industries of rubber tires, oil/petroleum and motor companies to dismantle the electric trolley systems. The federal push over the cliff came in the form of Public Utility Holding Company Act of 1935 which ended the subsidy of the electric street car by their electric company owners. This was the end of the era of public transportation, as many of these trolley systems simply folded. The cities which didn’t get bus systems were now reliant on automobiles. Federal support of road building after WWII clinched the primacy of the automobile.

Similarly, air conditioning was first unit invented in 1902 by Willis Haviland Carrier, but was not broadly implemented in residential homes until the late 1950’s/ early 1960’s, once the “summer-peaking” gas fired central power plants were built. Again, a public/private partnership.

Small Car Technology in the 50s

And now we are paying the price for these changes. Air-conditioning and central heating effectively eliminated any architectural considerations for climate, and was the demise of the great American invention – the front porch. With it went the neighborhood interactions, and an entire social structure. The reliance on automobile transport in the suburbs becomes an expensive proposition as gas prices continue to increase. Suburbs also isolate an aging population.

So what technology do we want for our future, and how might our government entities support this change? On the energy front, photovoltaic power promises some significant future improvements in the percentage of solar power per the same size panel. Government support is needed to help utility companies establish net-metering agreements, and also to allow for purchase of KwH production in excess from consumption. This will support the development of more net-zero houses, a hedge against future cost of utilities.

The technology curve for high efficiency hot water and HVAC appliances is sufficiently developed to be truly market ready. The US can follow the lead set by Canada by establishing a target date for mandatory adoption of these 98% sealed combustion condensing units, providing not only an increase in energy efficiency but effectively eliminating the danger of back-drafting of noxious gasses into our homes.

From a broader perspective, can we support the return of public transport, community centers, front porches? Where electric companies once subsidized public transport, now the responsibility lies on our central government entities. Not only to provide financial support, but also land management which allocates transportation corridors and zoning which encourages high density housing and community based businesses around transportation hubs. These decisions start at the local council level.

I encourage us all to think about forming our future. I hope that history will mark these years as the beginning of the new era, the final shifting away from the post-war consumerism and an embracing of mankind. It is our choice, will we drive technology – or will it drive us?

The Real Cost of “Safe” Air

The tighter the building envelope, the greater the attention to indoor air quality. In past blogs we’ve looked at ways to tighten the envelope, to balance the air throughout the building, and to provide replacement air. But what about the actual quality of the air? Let’s look at some steps to provide “safe” indoor air.

Step one. Control the source pollutants. When building new homes, this includes installing fans venting to the outside for all bathrooms, kitchens, and maybe even craft rooms or mudrooms. It also means storing paint (and paint thinner) and other such noxious VOC emitters in an outdoor space.

This step includes the inspection of combustion gas inspection in the furnace room. Let me share a little story… I came home for Christmas to find no heat had been turned on in my new house. I went down to fire up the new furnace, only to discover there was a large leak in the gas line. Some quick research revealed that the governing codes in the U.S. don’t actually mandate that a gas appliance be fired and inspected upon install. Indeed, common practice in new construction (in Utah) is to NOT activate any of the appliances which might be connected to the air filter, as the construction dust might clog the filters. However, there are also no provisions for later servicing.

In this incident, the gas leak was large enough to hear a hissing sound. But what if it had been a small leak? A new homeowner might have fired up the furnace, installed a gas stove, and never known there was a gas leak until the house blew up. It happened just a month ago in our town. So – don’t assume that combustion safety testing has been done. Specify it in your contract.

Step Two. It’s simple. You really don’t want to be in a position where you and your furnace are fighting for the same combustion air. A tight house can easily be depressurized by turning on the exhaust fans in the house. To my knowledge, there is only one fresh air intake which can be set-up to activate based on pressure differential , the Ultimate Air. Otherwise, that house is going to be sucking for air – and will find the easiest pathway – a hole to the exterior. That would be the flue stack for a typical Class I appliance – the kind with a little “chinaman” cap on the top. When air is pulled down the stack, all the combustion gasses which were supposed to be exhausted are now spewing into your home. Toxic fumes build up quietly, but can be deadly. Early signs can be flu-like symptoms, headaches, feeling drowsy. People die every year from this very problem of backdrafting. Don’t play this game – choose the “safe” air option - choose sealed combustion appliances.

One common complaint is that these sealed combustion units are more difficult to install. Different, yes. The venting uses PVC piping since the flue temperatures are much lower. This actually simplifies the air sealing around pipe penetrations, as the surrounding materials no longer have to be fire-rated. These condensing units do “drip” their condensate, so they need to have a connection to a drain, but this can be a longer length of pipe if necessary. In other words, nothing in the installation which would be a dealbreaker.

Energy Savings Calculator

How expensive is a sealed combustion unit? In Canada, this is the only choice as of Jan 1, 2010, when the AFUE performance level for gas-fired furnaces was raised to 90%, which means all sealed combustion units. Canada is colder overall than the US, so it makes sense from an energy standpoint to go to the higher efficiency. But in the US, there is still a choice. While higher efficiency units may not pencil out in short term cost savings for a mild climate, the potential danger of combustion gas spillage should be enough reason alone to choose the sealed combustion.

So – let’s look to a long and prosperous New Year - and choose “safe” air.

Dear Santa, Please Bring me a Few GOOD Contractors

It is midnight and I’ve just spent the last 6 hours with an industrial sized shop vac mopping up 26 gallons of water from the brand new carpet in my super-duper, net-zero, LEED something home. And why, may you ask, do I have a swimming pool in my basement? Ah – because the landscape contractor did not see fit to fill in the big excavation right next to the house which he dug to install the sprinkler system. We’ve had lots of rain, water finds the big hole, it seeks the path of least resistance, finds the old concrete foundation wall (which had no waterproofing when installed in 1936) and percolates through to my nice new carpet.

Sustainability includes durability. And durability is all about understanding the forces of nature, and setting up systems which will prevent any damage to the materials of the house. In the case of water – this means DRAIN the RAIN. Simple. Something I expected a landscaper to do, especially since it is spelled out in the LEED for Homes – points which he was supposed to be documenting.

But I was in Virginia, not in Utah, and not able to supervise. But REALLY? Is our industry so bad that the client has to supervise the worker? And yet this has been my experience on almost every phase of this house. There have been a few notable exceptions - carpet install, insulation company, sheet metal , and my current carpenter. And while I chided myself for somehow choosing the worst of the crop, the volumes of stories of similar and worse experience tells me that I got off easy - probably because I was effectively a site super – which oversaw the GC and the subs.

Sustainability requires a buy-in and commitment from every worker. It can only be achieved through the integration of the team of contractors, each understanding their role in the great game of building science chess. They have to think about how they contribute to the greater whole, how their work impacts the next guy, and how they can inform their predecessors what their requirements are for effective work. It’s called responsibility, collaboration, and thinking.

Santa, please show me some great contractors – ones who still treat homebuilding as a craft, workers who seek to improve their skills and are eager to learn. Santa, please send some inspiration, dedication and pride of workmanship to our industry – we really need it.

HAPPY HOLIDAYS!!!! HO! HO! HO!

Air Balancing

A building is a system. Not only a structural system, but also an organic system in balance with its surrounding environment. A dramatic change in one area may come back to bite you in another. For example, the great popularity of vapor barriers in the 90’s led to entrapment of moisture and subsequent rot of wood structures. And so I fear it will be with indoor air balancing.

While good air barrier detailing, and continuous insulation is not yet common, it can be achieved with known materials and methods. In fact, one of the issues in the ICF world has been builders who achieved super tight houses without too much effort, and then are tripped up by the HVAC portion. The HVAC is still sized by rule of thumb, and more often than not, the systems are considerably oversized. They kick on infrequently and for short durations, so the air is not sufficiently circulated or, in the case of A/C – dehumidified.

The industry association, ACCA, has developed software to address the sizing issues. In fact, Manual J, the program which determines the HVAC design load, is required by the IRC. Yet, its use is still spotty in most parts of the country. But Manual J should be just the start. There is also the Manual S, which would help choose the appropriate system, Manual D for duct sizing, and the Manual T, designed to identify and prevent drafts and stagnant air problems caused by improper sizing or incorrect equipment selection?

We have the software, but do we have the solution for air balancing and ventilation? No. Because the technical tools, the process, and the stakeholder skills are not aligned. Let’s take a look at one model of super-insulated, airtight house – the PassivHaus. The PassivHaus Standard calls for a description of the ventilation system on the plan, with declaration of the layout, air flow rates, soundproofing, filters, supply and return air registers, outdoor air intake and exhaust air outlet, insulation of air ducts. Hmm.. just who is going to do this? Your Carrier rep? The architect? Do they use ACCA’s Manual T? Doubt it.

Pressure Balancing Inserts

An even more primal question is that of tapping into natural air flows. We used to use whole-house fans, combined with jumper ducts, transfer grills and transom windows to help balance the air in a house. With the reduced design load of a super energy efficient house, in some climates, all that might be needed is a small heat pump and simple core of ducted delivery, with a central air return. Of course, this calls for a floor plan designed to support a system of air diffusion.

And so again I call for a new category of professional. One who is proficient in energy modeling, air balancing, system design and commissioning. There are a few sources of training: Building Performance Institute, RESNET, Associated Air Balancing Council, National Comfort Institute, generally falling into either the Energy Auditor Camp or the HVAC Technician camp.  But it is the crossroads of these two fields which are the "green jobs" of the future, needed for the market transformation of Net-Zero and Passive Houses.

Nuts and Bolts of Air

That is exactly the problem. You can’t fasten air with nuts and bolts. So after the last two diatribes in the theories of air entrainment, I’ve been asked to give some practical advice.

First of all, air can move through the tiniest of holes – so put your detail man on this job. Step #1 is to draw the boundary. Start with the construction drawings, then look at the details of the connections. For example, what if you decide that the boundary will be at the sheetrock? This works for the walls and the ceiling and maybe even for the floor connection. If you have a second floor, this can also work. But what about the space in between the floors? Unless you include the air barrier detail in the framing, then this space now belongs to the great outdoors, which is about 16 degrees on my thermometer.

For information on an airtight drywall approach, check out - you guessed it- no the Tappet Brothers, but the BS Brothers – Joe and John. For airtight electrical boxes, we have one of our readers to thank for sharing information about Airfoil, an innovative produce developed by a “Superinsulated” home builder, Doug McEvers. I’ve always felt that the real advances will come from the field.

Another layer where an airbarrier can be located is around the exterior of the envelope. This works especially well if there are no overhangs, and the air barrier (for example Tyvek) can be layered with overlaps from the roof onto the walls. And, of course, the concrete in an ICF wall will give you the air barrier for the walls, which can be continued up into the roof with a dense-pack foam in the roof rafters. Just make sure the exterior layer of the ICF is continuous with the air layer of the ceiling/ roof.

Leave min. 3" clearance all around

For those of you who wonder what to do with can-lights, try the retrofit approach taught by the Weatherization program. Make a large sheetrock box (always wondered what to do with all that scrap sheetrock) which is at least 3” larger than the edge of the can. “Cap” the can light with this box, and seal it to the top of the ceiling.

… and next week – we’ll talk about air handling and Ventilation ….

Vapour vs Air Barrier

This elusive intermingling of air and water has been like a good mixed drink, fascinating but gives you a headache with too much thought. But I have been tackling this beast lately, and find that confusion has been very much mirrored in literature, codes and practice. So I will share my academic endeavors, and hope to shed some light on the matter.

The discussion of vapor barriers first emerged in the 30s and 40s, and was not distinguished from the function of an air barrier. This confusion may be due to the fact that some materials, such as glass or metal, can act as both. The distinction between the two is one of the most commonly discussed building science issues.

Let’s check the IBC 2009, the version the most widely adopted in the US (Canadians – I welcome your input here). Section 1405.3 Vapor retarders. Class I or II vapor retarders shall be provided on the interior side of frame walls in Zones 5, 6, 7, 8 and Marine 4. (Cold and cold/wet climates)
Class I: Sheet polyethylene, nonperforated aluminum foil
Class II: Kraft-faced fiberglass batts or paint with a perm rating greater than 0.1 and less than or equal to 1.0

For a little history, the old code and standards used to specify vapor barriers, which are less than a permeance of .1, such as a polypropylene or foil facing, now called a Class I vapor retarder. Note that the code added the option of the Class II, such as Kraft-faced fiberglass batts. Because each year of code is a version of the previous, it remains in the code, but has been "relaxed."

Interestingly, my word search for “air barrier” in the IBC 2009 came up with exactly zero – nada. Apparently, the Canadians require an air barrier system in enclosures that would be adversely affected by air leakage condensation- basically any buildings which have moisture susceptible materials in the walls.

So let’s go back to our little molecule of water suspended in air. Let’s say he hits that vapor resistant layer. Depending on the permeability of that material, he may or may not “diffuse” through. But, he is a smart little survivor, and knows that if he just moves over to the edge of that Kraft paper, he can find a hole that is plenty big to travel through. And off he goes on his little journey to wreak whatever havoc possible in the interstitial space. That is called convective vapor transport.

“ … the vapor transport is negligible compared to cutting a one-square-inch hole in that box and having just a modest air pressure difference between the inside and the outside. So what’s more important in controlling moisture transport? Air tightness.” Joe Lstiburek

Hence the importance of the Air Barrier System – which is continuous ALL THE WAY around the entire building envelope, strong enough to handle a full wind load, durable enough to last a lifetime, installed in a way that is not compromised by installers, stiff, impermeable and in full contact with the insulation. The air barrier system should be labeled and detailed on construction drawings and tested it with a blower-door test BEFORE sheetrock. Use only sealed combustion appliances (more efficient as well), and ventilate for clean indoor air.

Back to the vapour barrier - is it important? Even with a primary air sealing system, there may be point penetrations, or failures. When moisture does enter the envelope, you want to have a system of retarders to slow down the wetting process, because insulation needs to stay dry to function. This is why it is generally not as critical if the Kraft paper layer is not continuous. But in high moisture areas, such as bathrooms, a continuous vapor barrier (ie perm <.1) is good practice, as is the installation of a dehumidstat to activate the fan when humans don't remember to.

So the first line of defense to moisture is the air barrier. The second line is moisture barriers.

Women in Construction

To celebrate today, my 75th Blog - I would like share a personal accomplishment and perhaps gain a bit of audience buy-in. Look around the jobsite, the job trailers, architect offices, land development companies, and engineers offices. What is the percentage of women? Not much, yet women make up almost 50% of the total US workforce. Then – ask your “elders” about who was manning the factories, the backhoes, the machine shops during the second world war?

Gentlemen, fear not, this is not a column about crazed testosterone women taking over the workforce. It is merely an exercise in awareness.

Last night, I successfully launched a “Connecting Women in Construction” project, under the auspices of the AAUW (American Association of University Women). Our goal is to develop a model of mentorship and opportunities for hands-on experience for our female students.

The catalyst for this project was an observation made as students introduced themselves at the beginning of the semester. Many of the male students shared that they were following in the footsteps of role models, and aspired to high positions of management and ownership. By contrast, only few of the female students had any prior contact within the industry and their goals were correspondingly limited to “graduating” or “finding a job.” In other words, many of the guys in our path followed a cultural “pipeline” which led them to aspire to a successful career in construction. Girls have to select the pathway of stepping stones to get to the same starting place, often with little encouragement along the way. Hence our first goal - mentorship.


The second part of the program came as a request from our female students themselves. They want a chance to go out and build. Boys often gain some relevant construction experience because they have signed on to house building crews in the summer during high school. But the reality is that cultural norms make this a less obvious option for girls. Ironically, in our program we are now facing the problem that many of the boys also have no field experience.

And why should we hire women? Well, Balfour Beatty Construction has found women to be well suited for their new “project integrator” positions. My own research on interpersonal skills in teams indicates that women may be stronger in communication and teamwork. And both Lean Project Delivery and Sustainable Construction (Energy Efficiency, Durability)have documented the need for well integrated teams and cooperation among trades to achieve the desired results. In previous blogs, I’ve spoken of the A/E/C industry’s voiced need for “people” skills, collaboration skills. Sounds like a good reason to me to explore the contributions women can make to address this need.

So, for all of you out in readershipland - (which, according to the stats tell me is growing significantly) - please be aware of stereotypes, mentorships and opportunities. Offer to help the Girl Scout Troop with a construction badge, offer a day in the field to girls in high school, or those enrolled in a community college. Buy your daughters some Legos. And mostly, be aware of opportunities to help women take the first step in joining our industry.

Surviving the Great "Air" Force

On my walk home tonight, my thoughts were almost solely focused on air. How might I tuck my head even further into my collar to avoid the cold wind sucking the heat out of my body. Why my nice “winter” woolen pants were rendered completely useless for warmth as the cold air sliced right through to turn my legs into frozen toothpicks. The temperature was only 19 degrees – but the wind chill factor dropped it to an effective cold of 4 degrees.

This same cold air can really affect the comfort level in a house. Last week, as we were testing out the blower door on a “training” house, we were astonished to discover just how interconnected the interstitial elements (i.e. the framing cavities) were to the interior of the house. Imagine the scenario-we are sucking out the air through an upstairs outside door, to put the upstairs into negative pressure. Even with the stairway doors closed, the downstairs also went into negative pressure. The culprit? Access doors on both floors to the plumbing behind the tubs/ showers. Had this particular house not been airtightened through a weatherization program, we would have been able to look up that shower space right into the attic – effectively connecting the exterior cold air with the entire house.



You Tube - Attic Air Leakage

 Air - It is the ultimate riddle, indispensible but not visible, needed by both humans and combustion appliances, carries moisture which we want – but not too much. At some point in previous blogs, I have puzzled over how we could ever deploy the great wisdom of the Lstiburek and Straube team to help homeowners improve their comfort levels and inch toward a higher energy efficiency and passive survivability. With all sorts of disclaimers, I would venture to say that we start with air.

Where is the air barrier in our house? Is it continuous – and where does it leak? Is it in continuous contact with insulation? In which direction is it carrying moisture? Do we want to wrestle with combustion appliances for this air – or can we vote in our favor and replace the appliances with sealed combustion units, or electric appliances. When we install an HVAC system, is the air flowing evenly throughout the house, is there an equal exchange of air and are we filtering the air?

Congress is proposing a Home Energy audit program for remodels, which calls for BPI and RESNET auditors. I am all for improved education and training, not only for analysts, but also to support ACCA’s efforts get the HVAC industry to embrace it’s long forgotten “V” (ventilation) and show some respect for the greatest force in energy efficiency, comfort and safety - the “air” force.

Creative approaches to reducing C&D Waste

Reducing waste is the function of a good estimator, careful procurement and constant jobsite management. C&D waste can be recycled, and creative contractors know how to increase the LEED points for recycling by inflating the weight with recyclable concrete and landscape stone, thus masking many of the other materials. But this isn't creativity - this is just tricking the system.

Recycled - YouTube Link

Real waste reduction can come through design. Standard American Design (S.A.D.) can design to material modulus - as we saw in our “Waste or Value?” blog posting.But today’s posting is about creativity. Dan Phillips, of the Phoenix Commotion, proposes that the homebuilding industry has been commoditized both for several reasons:

• The nature of our culture to maintain the consistency of the aperceptive mass (keeping known patterns or materials because they feel right).
• Keeping up with the Jones – and the vanity to conform to an identified groups standards, and the corollary emotion of fear of venturing too far away from market appeal for resale purposes.
• The Apollonian nature of our culture which prefers perfect, pre-determined , standard design and materials.
• Industrial revolution which has created so many standard materials and completed components that creative construction is now more difficult.

So we build custom houses which are really just a rearranging of the commodity floor plans and materials as the next house. Our building codes are very influenced by materials manufacturers, which push their products to become the standard path of compliance. For example, a remodeler may be faced with the dilemma of replacing diagonal board sheathing with the code specified shearwall plywood, or be forced to hire an engineer to approve the existing boards, and then have to convince the building official to allow this “exception.” More money for Georgia-Pacific. And, more waste, as the old material is thrown away.

Recycle bottle - lamps YouTube

We look to examples like Dan Phillips, who have been able to work past the barrier of the code, and have adopted the creative approach of using salvaged material. While his houses may be a bit too “organic” for some people’s taste, there are also fine examples of very traditional designed houses, like the Rex project, which re-used all of the existing house to rebuild new. The house stays within our comfort zone of cultural expectations, while tapping into the appeal of “green building,” for example with this recycled bottle chandelier.Note that both of these builders have demonstrated that this is a cost effective approach.

This green building, or sustainability, may be the cultural cry for a return to creativity and individuality. We are at a crossroads. Just as a vegetarian can choose to either stick to the Standard American Diet (SAD), only using “faux” meat, or choose to embrace the creative cuisine of vegetables and grains which is prevalent in most of the world outside of the US…. so can builders either stick to SAD (Standard American Design) with a few “faux” materials, or embrace the creative construction which comes from harvesting materials locally, choosing unprocessed materials, and embracing the non-conforming nature of salvaged materials.