Rethinking Durability

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Rethinking Durability

Lessons learned from a visit to a Roman aqueduct

Posted on Oct 23 2013 by Martin Holladay
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Does durability matter? Most green building advocates seem to think that green builders should always aim to build durable structures. My own opinion differs; in fact, as I explained in a 2009 article on the topic, it’s hard to see any correlation between durability and “greenness.”

I recently had an opportunity to reconsider the advantages and disadvantages of durability when my wife and I visited the Pont du Gard in Languedoc-Roussillon, France.

The 2,000-year-old Pont du Gard is a remaining section of what used to be a 31-mile-long Roman aqueduct that conveyed water from a spring in Uzès to the city of Nîmes. Most of the aqueduct was buried; the buried sections of aqueduct resembled a masonry culvert lined with waterproof plaster. But Roman engineers knew that they couldn’t bury the section of the aqueduct that crossed the Gardon River. The technical solution to the river crossing was a 160-foot-tall stone bridge — the Pont du Gard — with an aqueduct on top.

The Pont du Gard is built of dressed limestone blocks, assembled without mortar (see Image #2 at the bottom of the page).

Look at the people walking across the lowest span of the bridge to get an idea of the bridge's scale. The bridge is 160 feet high.

In ancient Roman times, the aqueduct conveyed 44 million gallons of water per day to the public baths, fountains, water spouts, and cisterns of Nîmes. (That amount of water would adequately meet the needs of 138,000 modern American homes.)

Without any maintenance, the aqueduct continued to supply fresh water to Nîmes for 300 to 400 years. Unfortunately, mineral buildup gradually reduced the size of the aqueduct’s channels; eventually, in the 4th or 5th century A.D., the aqueduct ceased functioning.

For centuries after water stopped flowing through the aqueduct, the Pont du Gard continued to be used as a pedestrian and equestrian bridge.

A gravity-fed system

The Pond du Gard has long been a pilgrimage destination for civil engineers with a historical bent and French stone masons.

The simple existence of the bridge is impressive. Because of the weight, shape, and careful placement of its massive stones, the bridge has withstood 2,000 years of floods and at least one major earthquake. It is an engineering and aesthetic masterpiece, at once impressively massive and airy.

I have a rudimentary understanding of gavity-fed water systems. Years ago, with the help of family members and friends, I used shovels to dig a 300-foot trench for a buried waterline connecting a Vermont spring with my off-grid house. Like the aqueduct in Langedoc-Roussillion, the buried pipe followed a gentle grade from the spring to the kitchen faucet.

It’s hard to imagine how the Roman surveyors who laid out the path of the Nîmes aqueduct were able to survey a 31-mile route through hilly, wooded terrain. The difference in elevation between the beginning of the aqueduct (its source) and the distant cistern in Nîmes where the water was delivered is only 56 feet — which means that the aqueduct has a gradient of 1 in 3,000. If you have ever tried to maintain a consistent slope on a 20-foot-long PVC drain line, you can perhaps imagine how difficult it might be to maintain a slope of 1 in 3,000 for 31 miles, in spite of gulleys, hills, and boulders.

The surveyors couldn’t make any mistakes, because the crossing of the Gardon River was going to require an engineering tour de force. The project design called for the highest bridge in the Roman empire, so there wasn’t much wiggle room. If the bridge were any higher, it might be unbuildable; any lower, and there wouldn’t be enough of an elevation difference for the water to reach its destination. Yet the Roman engineers and masons met these almost unbelievable specifications, without any transits, power tools, or earth-moving machinery.

Modern bridges don't last as long

A visit to the Pont du Gard is moving — for modern stone masons, surveyors, civil engineers, and ordinary tourists. The wooded river valley is a beautiful site, and the soaring arches inspire awe.

After 2,000 years, the bridge still looks great.

[Photo credit: Alan Vickers.]

Meanwhile, back in the U.S., we're busy rebuilding 40-year-old bridges on the Interstate highway system, simply because the bridges have reached the end of their useful lives.

One obvious conclusion — that we don’t build bridges like they used to — is only half true. After all, the poorly made Roman bridges — from simple log-over-a-river bridges to more sturdy bridges that have since succumbed to flash floods — have disappeared, leaving only the masterpieces for us to contemplate.

Should all structures be this durable?

Roman engineers and masons proved that it’s possible to build a durable structure. That raises some questions for today’s engineers and builders: Should we be striving to emulate these Roman builders? If so, what types of buildings need to be durable?

Several answers to this last question have been proposed. However, it's hard to come up with any hard and fast rules for durable buildings.

Important monumental buildings. Buildings in this category include cathedrals, libraries, museums, and university buildings.

One ancient example of a durable monumental building is the Roman coliseum in Nîmes. After 2,000 years, it’s in great shape, and is still used for regularly scheduled bullfights. Of course, the coliseum originally served as a venue for gladiatorial combats and the execution of common criminals. In my opinion, buildings used for capital punishment don’t really need to be durable; I hope that modern buildings used for this purpose will soon become obsolete.

At the nuclear reactor site in Satsop, Washington, Albert Rooks measures the thickness of a poured concrete wall.

Buildings that are part of major infrastructure projects. A modern example of a building in this category would be a nuclear power plant. How durable do we want our nuclear power plants to be? Well, they should be durable enough to contain the radioactive material in their cores — but we probably won’t want to have to look at these nuclear reactors 2,000 years from now. (Paradoxically, nuclear reactors are both not durable enough — because many of them have developed dangerous cracks — and way too durable, since it will take decades to demolish them after they’ve been shut down.)

Some nuclear reactors, like the WPPSS reactor in Satsop, Washington, were obsolete even before they were commissioned. (The Satsop reactor never went online.) Unfortunately, these reactor buildings have walls that are made of reinforced concrete 5 feet thick, so they are quite durable — much more durable than necessary.

[Photo credit: Dianna at TheseDaysOfMine.com.]

Beautiful buildings. When a building is beautiful, it’s nice if it’s also durable. Here in Vermont, a typical example of an old, beautiful building is the classic post-and-beam dairy barn. Many of these handsome barns are now between 100 and 150 years old.

These utilitarian buildings were used to support rural businesses; after all, the livelihood of Vermont farm families depended on the income they got from selling their cream. The penny-pinching farmers who built or commissioned these buildings weren’t interested in ornament of architectural flourishes; they simply wanted a practical building that was affordable.

Surprisingly, these simple requirements led to the design and construction of graceful buildings that are a joy to behold. The 21st century equivalents of the dairy barns of yore — the buildings that are erected to accommodate modern business enterprises — tend, in contrast, to be quite ugly. For example, many modern retail stores, warehouses, and factories in Vermont are simple flat-roofed rectangles with steel siding. This raises an interesting question: why did the economic constraints of the 19th century produce beautiful buildings, while the economic constraints of our time result in ugly buildings? (That’s a question for architectural historians, I suppose, not green builders.)

Unfortunately, many of Vermont’s handsome old barns are now composting. I’m sure that lovers of beauty wish that these buildings were more durable. But if barn owners don’t have any cows — and most no longer do — it's hard to justify the cost of a new barn roof. Without cows, these buildings are doomed.

So the lesson here is: even beautiful buildings won’t be maintained if they outlive their usefulness.

All buildings. Many green builders propose that every building should be durable, because replacing and repairing failing buildings is expensive and environmentally taxing.

It’s hard to defend this proposition. After all, not every building needs to last 1,000 years. Inexpensive temporary buildings can be built with recycled materials, and it’s somewhat arrogant to imagine that we know what type of buildings our great-grandchildren will want to look at or live in. (For more on this topic, see Green Homes Don’t Have To Be Durable.)

How about single-family homes?

What if we limit our focus to single-family homes? How durable should these buildings be?

In light of the fact that many homes get additions or extensive remodeling every few decades, and that our neighborhoods rise and fall in desirability, it might be better to rephrase the question: What elements of our homes need to be durable?

It’s hard to come up with many components of most homes — other than roofing, siding, flooring, and septic systems — that need to be durable.

Kitchen cabinets? Not really. How many cooks would really be satisfied with 50-year-old kitchen cabinets?

Bathroom fixtures? Most homeowners don’t want 50-year-old bathroom fixtures. (For one thing, old toilets waste water.)

Windows? Maybe. But newer windows perform much better than old windows. Moreover, many homeowners prefer larger windows than homeowners were willing to accept 100 years ago. When people tour an old home, they often say, “It’s a beautiful house, but it’s a little dark and depressing. Installing larger windows would help a lot.”

Most people think that durable roofing and siding makes sense. Yet almost every week, someone posts a question on GBAGreenBuildingAdvisor.com about improving the R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of a roof assembly or wall assembly with a thermal bridgingHeat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. problem. The usual advice is, “When it’s time to replace your roofing (or siding), you can install a continuous layer of insulation to address the thermal bridging.” If the home has asphalt shingle roofing, the homeowner may only have to wait 5 or 10 years to do this work. However, if the home has durable roofing like slate, it may be impossible (or ridiculously expensive) to implement this advice.

I like durable flooring — for example, oak or maple flooring that is at least 3/4 inch thick. But other homeowners say, “I’m sick of the look of this hardwood,” and happily rip out 50-year-old flooring to install ceramic tile.

It turns out that almost every aspect of our built environment — the location of our buildings, the size of our rooms, the orientation of our rooms, the R-value of our thermal envelopes, the size of our windows, the location of our electrical outlets, the diameter of our water and drain pipes — is subject to change over time.

The Roman temple in Nîmes was dedicated to the worship of the Roman emperor. This practice arose when Roman emperors decided that they were just as worthy of worship as any god.

Unfortunately, there is no reason to believe that today’s green architects and green builders have any better idea of the lifestyles of the future than anyone else. (For more on this topic, see Designing for the Future.)

Did the Romans have the right idea?

The Romans built durable temples to worship their emperors. These buildings are beautiful, but they have certainly outlived their function. The same can be said for the venues where Romans executed their prisoners.

The Romans also built durable roads, bridges, water supply systems, and sewer systems. It’s easier to praise the Romans for these projects than it is for their temples and execution sites.

At this point, it seems appropriate to introduce the scene from Monty Python's Life of Brian when the anti-Roman revolutionaries ask an important question: "What have the Romans ever done for us?"

Chapeau bas, messieurs

While the engineers and surveyors who designed the Pont du Gard may have enjoyed lives of privilege, the construction workers who dressed the necessary limestone blocks probably didn’t have an easy life. But whether the workers’ lives were comfortable or harsh, they ended up building a conduit that delivered fresh water to tens of thousands of people for hundreds of years. They also created an object of beauty that has endured for two millennia. That’s more than most of us can say.

To these Roman construction workers, I remove my hat and bow. Well done.

Martin Holladay’s previous blog: “Ductless Minisplits May Not Be As Efficient As We Thought.”


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Image Credits:

  1. Unless otherwise noted, photos are by Martin Holladay and Karyn Patno

1.
Oct 23, 2013 12:19 PM ET

Regarding Satsop & WPPS
by Dana Dorsett

The notion that the Satsop reactor was obsolete is a bit oblique. Satsop the handful of other nukes under construction under WPPS at that time were simply not needed on the regional power grid. With escalating costs due to construction delays, it became apparent that it would not be able to compete economically with the incumbent large-scale hydro power driving that regional grid (both then and now.)

With no markets for higher-priced electricity on the horizon and rising costs, the WPPS was unable to make good on their bond payments, leading to the largest bond failure of it's kind in US history, a failure that has rendered nuclear power un-financeable in the US without governmental guarantees ever since. (Often impossible to finance even WITH guarantees.)

Similar designs have been completed & commissioned since then in markets where the was needed and could compete on price. It's perhaps inaccurate to call it "obsolete". "Redundant", or "uneconomic" or "an ill timed investment" would be closer to the mark.

It's probably a good thing that the WPPS fleet was never commissioned, and large scale reactors of that ilk have a horrible track record of hitting the financial benchmarks promised, even with loan guarantees. And it's not just a US thing- the 3 gigawatt Hinkley Point C reactor currently under construction in the UK is only able to attract financing with a guaranteed (and inflation adjusted over time) 15 US cents/kwh for it's output for 35 years, which is more than the cost of baseload off-shore wind power in the UK, and WAY over the cost of onshore wind & PV (even in the not so sunny foggy-dew British Isles.) Just the cost of the generation that has to be built just to back up that reactor for when it has suddenly go off line is daunting. It's the opposite of "energy security", and about as bad an investment in energy infrastructure that the UK taxpayers & ratepayers have ever bankrolled, given where the ~$40,000,000,000 USD of recently adjusted estimate (and not guaranteed limit) total capital cost MIGHT have been spent.

But is uneconomic and unnecessary the same thing as obsolete? Maybe, if that's the last of it's kind ever built. In 2013 it's arguable that the existing power grid model of large-scale centralized generation has become obsolete, large nuclear being just part of that model. We'll see.


2.
Oct 23, 2013 2:02 PM ET

"Obsolete before it was commissioned"
by Martin Holladay

Dana,
My "obsolete before it was commissioned" comment was a quip intended to highlight the stupidity of the developers and regulators who approved the massively expensive project in the first place.

"Ill-timed" may indeed be more accurate -- but "ill-timed" is overly charitable, I think. How about "unbelievably stupid"?


3.
Oct 23, 2013 3:32 PM ET

Unbelievably stupid works!
by Dana Dorsett

Unbelievably stupid surely applies to Hinkley Point C, and probably the Vogtle 3 & 4 in GA too.

Some of these projects would be cheaper & better off to take the write-down now, before they load the fuel. As expensive as the WPPS fiasco was, it's cheap compared to the total cost of having to decommission a nuke that didn't run anywhere near the lifecycle built into the financial models. Given that the lifecycle cost of utility scale PV in 2013 in the US is cheaper than just the fuel costs of a US nuke, with onshore wind being even cheaper than that, it's not clear how you're going to get another 35-50 years of service out of big-iron generators (any type), new or existing. Heavy hydro won't be going away, but nukes & big fossil burners are too expensive to fuel & maintain in a smarter-grid environment heavily supplied with distributed zero-marginal cost renewables.

"Ill timed" also works, even for Satsop. If they had waited for electricity markets to expand to where it was actually needed before breaking ground they would still be waiting, but that's what timing your investment is all about, eh? Even the most aggressive assumptions about growth in power sales didn't really support the scale of construction WPPS was going for. They seemed to be going at it with a "if you build it, they will come" mentality, a concept almost worked in the power industry the 1930s & 1940s, but by the late 1950s even finishing some of the Roosevelt era dam projects didn't quite make sense, but they did it anyway, and all but forced it into the market with "all electric home" incentives and discounts, advertising resistance electricity space-heating as modernity.

By the 1970s when the WPPS nuke plans were being hatched there was ample reason to question who would be buying up all that excess power, and at what price. But at the time there were plenty of people in state government (including governor Dixy Lee Ray, formerly the head of the Atomic Energy Commission) who were steeped in the heady cooling water outflow, with the conviction that expanding energy use would continue unabated forever, despite clear signals in the marketplace (from the oil price shocks, and elsewhere), that energy would have to get cheaper to keep growing at prior decades' rates.

Nuclear power went from "Too cheap to meter", to "Too expensive to matter" in about one generation, two at most. But some haven't gotten the memo yet, ergo Hinkley Point C. It remains to be seen if the Little Nuke that Could designs such as scalable molten salt reactors can beat those economics. I'm fairly pessimistic about their prospects, but could see TransAtomic's design becoming economically rational as a means of processing the existing stockpile of spent fuel rods into power + dramatically reduced half-life of the re-spent fuel. It's worth building a few to find out. Designing and building containment for radioactive waste that would be reliable for 100,000 years without much maintenance isn't something humans have any experience with. But containment for the ~500 years it would take for the molten-salt reactor's waste to cool off after extracting most of the rest of the energy in those spent fuel rods is something we can probably handle.


4.
Oct 23, 2013 8:37 PM ET

Martin
by Malcolm Taylor

A very timely blog. Durability plays a very small role in which residential buildings in North America are abandoned or torn down. Demographics, regional economics, and fashion are much larger factors.
There is also a good argument to be made that the older building in cities like New York or Montreal (like much of Europe), benefit more from their place in a well planned urban environment than their inherent durability. When something is a functioning part of a whole you tend to value it more.

My own approach is to try and distinguish which elements of a building will need periodic replacement and detail them to make that easier. The way windows are installed, or even simple things like whether step flashing is nailed on to the roof or to the wall can mean a great deal to a future owner facing these tasks.


5.
Oct 24, 2013 6:14 AM ET

Response to Malcolm Taylor
by Martin Holladay

Malcolm,
The chambre d'hôtes (bed and breakfast) that my wife and I stayed at near the Pont du Gard was an old stone farmhouse. It was lovely. Many people might say, "It's a good thing that the old farmer who built this house 300 years ago made it durable."

But the house had undergone a recent renovation. I examined the work and talked to our host about it. The building had basically been gutted. It had new flooring, new wall finishes, and mostly new ceilings. It had new plumbing and electrical work. It had a brand new heating system. The bathrooms and kitchen were built from scratch. The windows and doors were all new. In some of the rooms, they left the old walls exposed -- and those sections of wall were uninsulated stone.

So it's fair to say that the cost of renovating this farmhouse was basically the same as building a new house, except that the work may have cost a little more, because there were stone walls in the way of the work. Oh, and except for the fact that the house they ended up with didn't perform very well from an energy perspective, because of those uninsulated stone walls.


6.
Oct 24, 2013 8:19 AM ET

How to measure durability
by Reid Baldwin

For any structure, the probability of the structure surviving X years declines as X increases. For a house, it is not important that the median lifespan be >100 years. The 90% lifespan is a better way of measuring house durability.


7.
Oct 24, 2013 8:37 AM ET

Edited Oct 24, 2013 8:42 AM ET.

Response to Reid Baldwin
by Martin Holladay

Reid,
I'm not sure I understand your point. Are you talking about durability, or durability estimates?

A researcher looking into durability statistics would probably gather data on houses that have either been abandoned or demolished. If you know the demolition date and the construction date, you know how long the house lasted.

Estimates of the lifespan of existing buildings are, of course, uncertain.

If you are looking at a set of houses -- for example, the set of houses built in Salem, Massachusetts in 1850 -- you could probably say that 90% of the houses lasted at least x years. But you can only determine that number if at least 10% of the houses built in Salem, Massachusetts in 1850 have already been abandoned or demolished.


8.
Oct 26, 2013 4:32 PM ET

Durability Metrics
by Reid Baldwin

Measuring durability probably wasn't a good title for my point. As you point out, you cannot measure lifespan until the end of the lifespan. However, we can design for a life expectancy probability distribution. That life expectancy distribution can be characterized by several points, such as how long before there is a 10% chance that the building will fail, how long before there is a 50% the building will fail, and how long before there is a 90% chance that the building will fail. The steps we take to increase the 10% number may not be the same as the steps that we would take to increase the 50% number or the 90% number. My point was that taking the steps to increase the 10% number is probably worthwhile. Taking the steps to increase the 90% number is probably not justified.


9.
Oct 26, 2013 5:31 PM ET

Edited Oct 26, 2013 5:37 PM ET.

Response to Reid Baldwin
by Martin Holladay

Reid,
I'm still lost. You wrote, "We can design for a life expectancy probability distribution."

Really? Can we do that?

All kinds of assumptions are built into that sentence. It sounds as if you know (a) Which neighborhoods will be desirable in 50 years, (b) Which style of home will be so cherished that it will be taken care of, and (c) Which type of homeowner will have a high enough income in 50 years to maintain their homes well, and (d) Which neighborhoods will be hotbeds of future teardown activity, because developers in the future can make more money bulldozing houses than fixing them up, and (e), (f), and (g) ...

I'm not as confident as you are. I have a long list of reasons why buildings are abandoned or demolished -- but the quality of the roofing or the existence of a rainscreen gap aren't on my list.


10.
Oct 26, 2013 7:45 PM ET

Durability
by Timothy James Robinson

Enduring service is one of the proper goals of workmanship in construction. We all know that the future will change the purpose for a building and the way it works. But the rule of thumb is whatever you had a hand in putting together, should still be going strong when the your work is deconstructed.


11.
Oct 26, 2013 7:55 PM ET

Edited Oct 26, 2013 7:58 PM ET.

Response to Timothy James Robinson
by Martin Holladay

Timothy,
I can't figure out whether your statement is a meaningless tautology or an impossibility.

You wrote, "Whatever you had a hand in putting together, should still be going strong when your work is deconstructed." Are you talking about when the components of the building are deconstructed or when the entire building is deconstructed?

If you are saying that the components of the building need to last until the day that a maintenance worker performs deconstruction of the (failed) components, that is a tautology. The components have to last until they fail; when the components fail, they are deconstructed and repaired.

If you are saying that the components of the building need to last until the building is deconstructed, that's a high bar. So the only roofing permitted is roofing that last for the life of the building? All roofing has to be slate or 16-ounce copper? And when acid rain eats through the copper, what then? The building is bulldozed?

Many building components need to be replaced before the life of the building is over. So what?


12.
Oct 28, 2013 11:08 AM ET

Durability
by Jim Baerg

An influential book on this topic is Stewart Brand's "How Buildings Learn" It's been 30 years since I read it, but I remember Brand advocating that we build assuming that buildings will be re-purposed. He advocating thinking about buildings having 3 systems; the first was a simple structure that supported and protected the space It should be built to last for centuries. The 2nd system, if I remember correctly, was the inner walls, which would get moved around on occasion as the building's use changed. Finally, interior finishes and mechanical systems would get replaced fairly regularly so we so the designer/builder should make them easily replaced.

Worth a re-read, I think.


13.
Oct 28, 2013 11:23 AM ET

Response to Jim Baerg
by Martin Holladay

Jim,
I certainly agree with your suggestion that How Buildings Learn is worth a re-read.

Many GBA blogs and articles have made the same suggestion. Among the GBA articles that discuss How Buildings Learn is this one: Low-Road Buildings Are Homeowner-Friendly.

Inspired by Steward Brand, builder Tedd Benson developed the Open-Built Platform, a system that attempts to "disentangle" building components that need to be remodeled regularly from the more durable building envelope. For more on Tedd Benson's Open-Built Platform approach, see these two GBA articles:

Unity Homes: Pushing the Boundaries of Home Building

Service Cavities for Wiring and Plumbing


14.
Oct 29, 2013 11:29 AM ET

Does attention to detail create durability?
by kim shanahan

My understanding of the green/durability question comes from the belief that increased attention to detail required to make a house tight, which then triggers the need for controlled air exchanges, will necessarily make a building better built and therefore more durable. As it is only a belief, and not a fact proven by time, since these notions are relatively new, we can only assume them to be true. And even if time proves them to be untrue, we do know the occupants are likelier to live in a healthier environment with relatively less expense.


15.
Oct 29, 2013 11:39 AM ET

Response to Kim Shanahan
by Martin Holladay

Kim,
You propose an interesting theory: that "increased attention to detail required to make a house tight, which then triggers the need for controlled air exchanges, will necessarily make a building better built and therefore more durable."

Unfortunately, recent decades provide plenty of counter-examples to undermine your theory. Many enthusiastic builders have jumped into the field of energy-efficient construction, and have managed simultaneously to make a house that is tight and in need of controlled air exchanges -- and have also ensured that the house has moisture problems and rots quickly. The cluster of EIFS failures is North Carolina is just one example of the type of failure I'm talking about.

Of course, builders who pay attention try to learn from each failure cluster, and strive to do things differently in the future. But not all builders pay close attention, and we're all learning something new every year. (For example, look at all the conditioned attics insulated with open-cell spray foam that now have damp roof sheathing.)

So, sadly, your formula for success -- make a house tight, and make sure the house has controlled air exchanges -- is insufficient to ensure durability.


16.
Oct 29, 2013 11:58 AM ET

Passive Houses too?
by kim shanahan

Martin,

Of course you are correct, but this statement gives me hope: "...builders who pay attention try to learn from each failure cluster, and strive to do things differently in the future." I also know you have documented spectacular failures of certain passive houses, specifically in Europe, that had underground ventilation systems for air exchanges.

But have we seen evidence that the notion of attention to detail and conditioned air exchanges that is taken to extremes in certified Passive House is creating disastrous unintended consequences?


17.
Oct 29, 2013 12:16 PM ET

Response to Kim Shanahan
by Martin Holladay

Kim,
Like you, I'm a big believer in reducing air leakage through building envelopes. I also believe that a tight home needs a mechanical ventilation system.

Most builders who believe in these principles are building good buildings. Yet we still have plenty of problems to keep us all busy, repairing and learning.

Lots of builders have trouble with wall flashing details and WRBs, so wall rot problems will be with us for many decades to come. To see some fun photos, check out All About Wall Rot.


18.
Nov 3, 2013 12:15 AM ET

Neglect tolerance
by James Morgan

Tolerance of extended periods of neglect is a characteristic of both the aqueduct and the old stone farmhouse but not so much of the airtight mechanically dependent structures that (for many good reasons) we find ourselves building today. Maybe in time we can learn to create homes that can remain sound even through the times we can't afford to actively maintain them.


19.
Nov 3, 2013 6:27 AM ET

Edited Nov 3, 2013 6:30 AM ET.

Response to James Morgan
by Martin Holladay

James,
You're right that (at least in centuries past) an old stone farmhouse could survive decades of neglect -- especially if it had durable roofing like clay tiles. But decades of neglect aren't kind to the interiors of any kind of home that people want to live in in the 21st century, because our interiors include kitchen cabinets, insulation, and electrical wiring.

If a house includes these features, as did the stone-walled bed-and-breakfast where we stayed in France, then decades of neglect would result in the need for a total gut rehab job. The stone walls don't protect the expensive stuff.


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