Ten years ago, Michael Maines wrote an article for GBA called “The Pretty Good House.” In the years since that article was published, GBA readers have followed along as a talented group of Maine builders and designers have refined the “pretty good house” philosophy, which advocates details that are more energy-efficient than usual, more cost-effective than those of label-based programs like Passive House, and environmentally responsible.
Now Taunton Press has published a handsome, well-illustrated hardback book, Pretty Good House, by four of the founders of the PGH movement: Dan Kolbert, Emily Mottram, Michael Maines, and Christopher Briley.
The authors are probably familiar to most GBA readers. Dan Kolbert is a builder and the author of a GBA article called “A Case for Double-Stud Walls.” Emily Mottram is an architect and one of the hosts of GBA’s “BS* + Beer Show.” Michael Maines is a designer and the author of countless GBA articles, including “Minimizing Concrete in a Slab-on-Grade Home” and “Windows in Thick Walls.” Christopher Briley is an architect and one of the hosts of GBA’s “Green Architects’ Lounge” podcast.
In short, these four authors have long been active members of the GBA community. Their new book is a practical introduction to basic principles of residential design and building science for homeowners, builders, and architects. The authors’ approach mirrors advice provided by Green Building Advisor—so if you’re a GBA fan, you should buy this book. If you’re planning to build a custom home, you should buy three copies: one to keep, one to give to your designer, and one to give to your builder.
Before I proceed with my book review, here’s a disclaimer: I’ve known these authors for years, and their book praises my work and the work of Green Building Advisor—facts that make me biased.
The book is one of the best available guides to residential construction. The authors are very familiar with the usual weaknesses of conventional construction practices, and provide a good introduction to how those who follow the Pretty Good House approach can affordably improve on these practices.
In addition to providing cogent explanations of building science principles, the authors publish excellent detail drawings. For example, the details on pages 100 to 102 do a great job of informing readers of a variety of wall-to-foundation transitions (including a wall with exterior rigid foam above a concrete frost wall with exterior rigid foam, a double-stud wall over a concrete frost wall without exterior rigid foam, a double-stud wall over a basement with exterior rigid foam, and a Larsen-truss wall over a frost-protected shallow foundation) and wall-to-roof transitions (including a cathedral ceiling with solid-sawn rafters and gusset-attached 2x3s below for added insulation depth, as well as a more conventional raised-heel truss for a vented attic, both shown over double-stud walls).
When it comes to residential design, most builders omit crucial basic steps, including optimizing the design with energy modeling software, accurately calculating the home’s heating and cooling loads, performing one or more blower-door tests, and commissioning the HVAC equipment. Pretty Good House covers all of these issues in depth.
The book recommends design simplicity and HVAC simplicity (page 61): “… Though … architectural frills add interest, they also add cost, often create wasted space, and are the hardest features to manage well in terms of water leakage, air sealing, and insulation. … And making a house more architecturally complex does not necessarily make it more interesting or attractive. The clean lines and utilitarian designs that follow the Shaker philosophy of simplicity, utility, and honesty are still considered fresh and beautiful.”
The book also quotes GBA contributor Carl Seville (page 26): “… So many buildings are overly complicated… If you just think simply, it’s really easy to build a high-performance house.”
The book includes ten case studies (all written by longtime GBA author Scott Gibson). Several of these case studies, including the Sugar Bush house on page 108 and the Low Chem house on page 178, are excellent examples of design simplicity.
Like most of us who write about building science, the authors of this book had to make assumptions about a big unknown: how many concepts does the typical reader understand, and how deep into the weeds is the typical reader willing to wade? The authors manage to strike a balance. Inevitably, some readers will occasionally be scratching their heads in confusion, while others will be left hungry for greater depth.
Fortunately, the authors direct readers who want more information to several web sites, including BuildingScience.com and Green Building Advisor.
Embodied carbon discussion
The book’s authors do their best to address an important hot-button issue in green construction: the need to reduce “embodied carbon” in building materials. To begin the discussion, they provide a clear definition (p. 155): “Embodied carbon is the amount of carbon that is released into the atmosphere to harvest, manufacture, and deliver that material to the jobsite.”
The basic tension in this discussion comes from the awkward fact that our planet cannot afford additional releases of carbon into our atmosphere at this time. On this point, Pretty Good House quotes Steve Konstantino, who said, “The most sustainable building is the one that is never built.” The authors continue, “It is a reminder that building things is not inherently good for the planet.”
So what’s a builder to do? Attempting to choose materials that are manufactured with relatively low levels of atmospheric carbon releases is probably the best bet (short of retiring). The authors admit that this is a tough issue, and simply advise readers to do their best (p. 157): “Every house should be as carbon-neutral as possible.” When it comes to materials, the advice is, “Use as little as possible.”
The authors make a bold claim when they write, “Pretty Good builders and designers are always brutally honest with themselves about the sustainability of their products.” I find this statement hard to believe, since so many aspects of the North American lifestyle are unsustainable.
The sentence can be read many ways; on its surface, it appears boastful. Naïve readers may assume that if they locate a builder who claims to follow the Pretty Good creed, the builder’s sustainability claims can always be trusted. But since I’m familiar with understated Yankee wit, I suspect that the authors are saying something else: “We all know that the work we do is unsustainable, and when we hang out drinking beer, we’re brutally honest about that fact.”
If you are a builder from Louisiana, Montana, or California, be forewarned: this book is deeply Maine-centric. That’s both a weakness and a strength. The authors have taken to heart the dictum to “think globally, act locally.” In response to their environmental concerns, they’ve created an intensely local movement. We need similar groups in every state and province.
Although the book includes one case study each from Massachusetts, Georgia, and California, the other seven case studies are all from Maine or Vermont.
The four authors, all friends and colleagues, have developed a consensus on the best way to build single-family homes in Maine. Readers from other states may nod their heads in agreement—or may roll their eyes at the prejudices of Maine builders. After all, everyone has an opinion.
Here are some examples of the Maine consensus:
Insulation (page 173): “Hands down, one of our favorite types of insulation is cellulose, both dense-packed and loose fill.”
Double stud walls (page 92): “Relatively affordable and simple to construct, the double stud wall is a hero of the PGH crowd.”
Basements (page 96): “We’re just going to go ahead and say it. Basements are not great spaces.”
Mineral wool insulation (page 175): “Mineral wool … is relatively high in embodied carbon and the binders that hold the fibers together are typically phenol and urea formaldehyde-based. … For these reasons, we typically relegate this product to exterior use only.”
Wood stoves (pave 185): “Save your fire lust for a winter solstice bonfire or a camping trip and enjoy your quietly humming heat pump the rest of the time.”
Solar hot water (page 201): “With the great advances in photovoltaic panels, we never do solar hot water systems anymore.”
These opinions were developed the old-fashioned way: by trial, error, and experimentation. The authors have reached conclusions about what works in Maine. In all cases, the authors explain their reasoning. Even when you disagree with some of their conclusions, you’ll probably admire their forthrightness.
On most pages of Pretty Good House, I found myself nodding in agreement. Here’s a sample of the book’s good advice.
The builder should insist on good envelope details (page 37): “An idea that emerged from one of our discussion group sessions was to make the building shell non-negotiable. The contractor, perhaps in conjunction with the designer, comes up with a wall section, roof section, air-sealing details, minimum window performance, rainscreen details, and so on. … They are based on the contractor’s experience, research, and expertise and are no up for negotiation when the budget gets tight.”
Complete the design before construction starts (page 39). “Simple things like thickening an interior wall for ductwork, making sure window and door trim or roof overhangs can accommodate a rainscreen, or designing a roof to maximize PV panels are very difficult to shoehorn in after construction has started.”
Do houses have to breathe? (page 67): “Do not put your health in jeopardy by eliminating the ventilation system and building a house that ‘breathes.’ Houses don’t need to breathe; people need to breathe, houses need to dry.”
Don’t say ‘U-value’ (page 86): “Note that it’s R-value and U-factor.”
Good advice on air sealing (page 103): Imagine “we’re building a boat. If it leaks, we sink and we die!”
Limit glazing area (page 135). “In most climate zones, the more glass you add, the worse the house performs from an energy standpoint.”
What about triple-glazed windows? (page 142): “In Passive House design, triple-glazed windows are required; in PGH-land we only recommend them, but they are often a sensible choice if you aren’t in a mild climate.”
Roof overhangs (page 145): “Doors should always have a protective overhang.”
Skylights (page 147): “While contemporary name-brand skylights rarely leak when installed properly, … they do tend to be condensation machines. It’s very rare to see one that doesn’t have water damage around the lower portions.”
Solar light tubes (page 148): “With the low cost and easy installation of LED fixtures, its usually better to burn a few watts of energy with artificial lighting than to install what amounts to a chimney through your roof.”
On ventilation rates (page 197): “There’s a catch: there is an energy penalty. … So the goal should be sufficient ventilation but not overventilation.”
On batteries for grid-connected PV systems (page 216): For power when the grid goes down, “… a fossil-fuel powered standby generator is usually more cost-effective than a battery system.”
One of the book’s strengths is its focus on “lessons learned.” For example, two of the book’s case studies include second thoughts over specifying ductless minsiplits. On page 25, the authors discuss the ductless minisplits that Carl Seville installed in his Georgia home: “There are two heads upstairs and one down, and while they have performed adequately, they have required more maintenance and repairs than Seville would have liked. In retrospect, he says he might have used ducted minisplits…”
Similarly, Jeffrey Adams regrets the installation of a single ductless minisplit on the second floor of his California house (p. 206): “Adams chose a ductless minisplit heat pump system consisting of two outdoor compressors and two indoor units, one upstairs and one downstairs. … In hindsight Adams would have looked into a ducted minisplit for better air circulation on the second floor, even if he had to sacrifice a little efficiency to do so.”
Two of the authors, Maines and Kolbert, collaborated on a renovation project that resulted in another “lesson learned” (page 221). They “decided to save as much of the existing one-story house as they could before adding a new second floor. … In hindsight, that was a mistake, Kolbert says. … ‘Now I tell clients that no matter how much we demo, in the end we’re going to wish we had done more. … We try to save what we reasonably can and usually end up wishing we had done a little more demolition.”
Green builders will note, of course, that this conclusion is somewhat at odds with the green impulse to favor renovation over new construction. It turns out that in green building, as in life, there is no black or white—only shades of gray.
A few quibbles
Pretty Good House is a monumental achievement, but there are inevitably a few flies in the ointment. One problem is the authors’ tendency to overstate the health risks of new homes, as when they write (page 2), “…Two decades into the new millennium … houses were being built by the millions, and far too many of them were being built badly. They are unhealthy for their occupants…” Really? There is scant evidence that new American homes cause health problems for occupants. In fact, the real health hazards—lead paint, friable asbestos, and extensive mold—are far more likely to be found in old homes than new homes.
A few statements are head-scratchers—for example, this discussion of “smart” vapor retarders (page 119): “…[Some] builders opt for vapor-variable membranes. These membranes are applied to the interior of the assembly (just behind the finish material). … The idea is that the [vapor-variable] membrane will block vapor from migrating into wall and roof cavities in the winter, when indoor humidity is low…” Whether indoor absolute humidity in winter is low or high depends entirely on the lifestyle of the occupants, but when compared to the outdoor absolute humidity, it is always high, not low. In fact, the reason you might want a vapor-variable membrane under your drywall is to address high indoor humidity in winter, not low indoor humidity in winter.
This discussion of continuous insulation on the exterior side of wall sheathing is also confusing (page 121): “… An ‘outsulation’ approach … [involves] installing layers of rigid insulation outside the sheathing, essentially wrapping the outside of the building in a continuous layer of insulation. … If that outsulation is a material such as mineral wool or rigid wood-fiber insulation, then it, too, is a vapor-open assembly and has a very low risk of mold or mildew.”
In fact, a properly installed outsulation layer of foil-faced polyisocyanurate (in other words, an exterior vapor barrier) also creates “a very low risk of mold or mildew.” It turns out that the vapor permeance of the outsulation layer is irrelevant to this discussion.
The authors imply that roof venting can keep roofs cool (page 123): “As with a rainscreen for a wall assembly, roofs can be vented. It is very common to install soffit vents at the eaves and ridge vents at the ridge to promote constant airflow at the exterior of the roof assembly just under the sheathing. This is often done to help keep the roof cool in the summertime…” In fact, roof venting barely affects roofing temperatures (especially in the upper sections of roof slopes). The most important factor affecting roofing temperatures is the color of the roofing.
The authors imply that houses need a continuous, uninterrupted vapor control layer (page 126): “Things to consider: … Have you defined the vapor control layer, and does it remain continuous around the whole building envelope?” This makes no sense. The authors are applying air-barrier principles to vapor control, and the lessons aren’t applicable. While an air barrier needs to be continuous, vapor control barriers do not. You need polyethylene under your basement slab, but you don’t need polyethylene in your straw-bale walls.
Weatherization contractors will be astounded to learn (on page 123) that “Spray foam should not be relied upon as an air control method.” Elsewhere (on page 177) this advice is repeated: “Some builders and architects erroneously believe that you can air-seal a project with spray foam.” Evidently, the authors are worried about homes with spray foam that has shrunk away from framing members, introducing air leaks. This type of shrinkage can occur, but such cases are relatively rare. Spray foam is such a useful tool for addressing air leakage in older homes that this issue deserves a much more nuanced discussion than the authors provide.
The book includes a few internal contradictions. Some of these contradictions, I suspect, may arise from the fact that the book has four authors. For example, whoever wrote the first part of Chapter 7 declared (on page 165), “Spray foam and other materials release isocyanates, which cause flu-like symptoms or worse.” That sounds alarming. A few pages later, whoever wrote the second part of Chapter 7 expressed this opinion (page 177): “A properly installed spray foam installation should be inert when complete. It will outgas VOCs as it cures but will cease once curing is complete.”
Whoever wrote Chapter 4 expressed (on page 104) an apparent preference for ERVs over HRVs: “With a tight house, you need to supply balanced ventilation through an energy-recovery ventilator (ERV).” Yet whoever wrote Chapter 8 declared (on page 198), “Much (virtual) ink has been spilled on whether and where to use an HRV or an ERV, but in the end the quality of the unit itself, along with the installation and the maintenance of the unit and ductwork, outweighs any advantage of one system over the other.”
Similarly, the author of Chapter 8 stated (correctly) on page 192, “Most air conditioners, including heat pumps, can handle dehumidification.” Yet whoever wrote Chapter 10 declared (incorrectly) on page 232, “Air conditioners rarely provide the necessary dehumidification, so a separate dehumidifier is usually needed.”
The wealthy-client problem
On page 47, the authors of this book describe one of the case study houses this way: “The house on Maquoit Bay is neither small nor inexpensive.” Like most designers and builders who focus on custom homes, the four authors of Pretty Good House work for a privileged elite—the small subset of Americans who can afford to build an architect-designed home. This fact doesn’t reflect poorly on the authors—it’s simply the way our economy works.
What do the homes described in this book have to do with helping house the world’s 8 billion people, or helping us transition to a future without a looming threat of climate disaster? I’m not sure. All I know is that each of us needs to look at our daily work, and find ways to reduce our environmental footprint.
I really love Dan Kolbert, Emily Mottram, Michael Maines, and Chris Briley. They are among the smartest, most conscientious designers and builders I know, and they care deeply for the future of our planet. Like all Americans, they are swimming in a sea of contradictions—designing and building fine homes for a small slice of the planet’s population as our world keeps getting warmer.
Pretty Good House is available for $34.99 from Taunton Press.
— Martin Holladay is a retired editor who lives in Vermont.
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