A review of writings past

Before the blog came the newsletter. I had a small email list that received a sporadic and erratic compilation of random information about energy and building science. I’m going to mine some of those for future blog posts, but in the meantime you can read them here: http://buildingdiagnosticsnh.com/newsletters.html .

Not all of them will be updated, but may be worth reading anyway. Today I’m highlighting a tough situation from years back. It illustrates why a planned ventilation strategy beats random air leakage every time. Read about the scary phone call here: http://buildingdiagnosticsnh.com/Files/December2010NewsletterPtII.pdf

I hope you’ll take some time to check out a few, and if you have any questions or comments leave them here.

If you need a personal consultation you can email me at wsmith@buildingdiagnosticsnh.com
or call or text me at 603-568-9404.

As always, thanks for reading.

Posted in Basics, Building Science, Energy, Indoor Air Quality | Tagged , , , , , | Leave a comment


When David Bowie released “Changes” in 1972 I was just short of legal adulthood. At that point in life everyone is experiencing change. 1972 was the tail end of the period we call the “60’s” (eras stubbornly refuse to acknowledge calendars), and change was somewhat turbulent.

Things smoothed out, as they tend to, but change never really stops. Everyday changes can slip by without causing a hiccup. Every now and then bumps happen, occasionally chasms appear. Somehow we cope, and perhaps grow. Like you, I’ve been through many, many changes. As a rule, I’m in favor of change. But if possible I like to have some input. So I’m making some changes, nothing earth shattering, but important to me.

First, Building Diagnostics will continue. The focus will change a bit, but I’m still committed to championing building science to help people have healthy and comfortable homes. And of course, businesses having healthy and comfortable work places. The main change will be how I approach working with my customers.

First, I’m ending the energy audit. Nothing I do will be called that. It was never a true or complete description of what a building science professional should be doing. If you want something by that name you can find it, but not here.

Why? Looking back over the years I’ve been in the building science field, the customers who have had the best results are the ones who I have had a relationship with beyond the initial building evaluation. Too many times I’ve handed over a report, often with detailed specs and goals, only to find out that either nothing was done, or worse, the wrong things were done.

Rather than one day evaluations, I want to work with people who are trying to solve problems with their homes, but need guidance through key portions of the work. Think owners rep. Beyond the initial evaluation I can work with homeowners to convey their goals to contractors. I can do quality control to see that work is completed properly. This is the number one point of failure, work that doesn’t accomplish what it’s supposed to. Also, I can offer translation services, contractor to homeowner, although as with any translation service, it’s an inexact process.

Also the DIY crowd could use some help. Most of the how-to books and shows are woefully misguided. The bad advice abounds, I’d like to change that. Lots of people are quite capable of doing competent work, but they really don’t understand how important the details are. A little coaching and demonstrating can work wonders.

I may offer some consulting for other building performance pros, such as spec writing, or reviewing action plans for areas that need tweaking. Whether you’re a homeowner, a business owner, a pro or a potential DIY’er get in touch if you’re interested. I have a broad knowledge base to work from, maybe I can find a way to help.

More thoughts will follow over the next few weeks, input is welcomed. Stay tuned to this blog and watch the website for updates as well.

Posted in Building Science | Leave a comment

Toxic attitude

Same wall

Same wall


The picture above tells a sad tale. A tale of bad project management, dispirited workers, and poor results for building occupants. I should note that I was the first person to access that space on the left in the 20 plus years since the building was constructed. I had to cut my way in because there was no access.

On the right is what you see. A pretty typical resort condo rental closet. No door, but you’re just here for a few days. But on the other side of that 1/2” thick drywall? That’s pretty nasty. Let’s run through what we can see and figure out what happened.

The drywall scraps are the big clue. Rather than tossing them out the window into the dumpster they just left them. Most job superintendents demand cleanliness as a basic element of job site safety and discipline. It’s not mean, it keeps things under control, and that’s good for everyone.

A well run job site is a wonderful place to be. The different trades, coordinated by a good super, work together and get along. Conflicts are minimal, and if they do arise they get resolved quickly with little ruffling of feathers. Assuming that the right plans are in place you get a well constructed building. Details attended to. Specifications followed. Quality construction.

Most general contractors and construction managers run good job sites. Some run great job sites. A rare few run really toxic sites. Incentives are all punitive. Cooperation among trades is rare and disputes are often ignored. Bad things happen. Insulation gets installed poorly, Poly sheets are slapped up with insufficient fastening and subsequent trades damage it and don’t fix it. And no one cares enough to worry about it.

Sometimes things get so bad that bathtubs get installed over windows and it never gets fixed.

img_0021-copyYup, same job.

I could go on about the faults in this space, and I will in another post. But I wanted to talk bout how stupid things happen. The sad thing is that the people who really pay the price are future occupants. Whether it’s a rental condo, an office or someone’s home, bad process leads to bad results.

When you’re hiring someone to build a building try to visit an in progress job. Is it neat? How’s the communication?  Don’t expect to see workers stopping to sing happy songs together, but if they’re at each other’s throats it’s a problem. Construction is a complex dance that needs a lot of coordination. Too many conflicts mean poor results. And that will be with you a very long time.

Posted in Basics, Building Science, Energy, Policy, Tools, Water | Tagged , , , , , , , , , | Leave a comment

Rubble, Rubble, Toil and Trouble*

My old foundation

My house. Yup, I had to remove the floors because someone brought in bugs.

Here in New England most of our older houses have rubble foundations. Rubble foundations are uncut stone, often called field stone. Even the best builders of rubble foundations had spaces between the stones that essentially connect the soil directly to the basement. Sometimes there is mortar in those spaces, but it’s very moisture permeable and only slows water down a little. Our present drought not withstanding, soil tends to be wet. The amount of water that evaporates from soil varies depending on many factors. Lots of numbers get presented with not enough information about how they were arrived at. Let’s just use the relative amounts “a lot” and “too much”. For our purposes that’s all we need to know.

Just a note here. I love rubble foundations. The best ones are tributes to the skills of the men (usually) who put them together. They’re beautiful. The stones were selected out of the piles to fit together really well and provide an impressively strong and durable foundation. Just don’t ask a modern structural engineer to certify them for a certain load. You’re likely to see a lot of twitching. It’s not a nice thing to do to an engineer. Also, don’t dig a trench next to the wall below the base level of the stones. While these things are really strong in compression* they do not deal well with tension*. I know at least a couple of structural engineers who should have known that. But I’m not going to digress that far.

Back to this water problem. Even if you’re not getting liquid water through your rubble foundation (lucky you) the evaporation is not helping at all. I routinely measure relative humidity levels in the high 90’s in rubble basements. Another point, houses with rubble foundations are our older housing stock. The leakage from floor to floor to attic is usually greater in these houses. So every level has higher humidity levels and that presents a whole series of possible bad outcomes. Read the post,  And One to Grow On, for background on why that’s a bad thing.

How do you fix this? You’ve got all these rocks sticking out at different levels, there’s dirt, cobwebs and probably some unidentifiable stuff that you don’t even want to think about. First, read my post, Oh, that’s gonna smell….  DO NOT, under any circumstances, wood frame a wall, install some porous batt insulation, and cover it with drywall. Read the title of that post again. Now, let’s get in the way-back machine and watch the opening scene of “The Graduate” and listen to the wise word spoken to Dustin Hoffman as Ben Braddock. “Plastics.”

That covers a lot of ground. Spray foam, sheets, and rolls of various types. Some are thick, some thin and some seem too flimsy to do anything. The next post will cover more specifics and we’ll start going over the pros and cons of different approaches.

Until then, don’t raise a stink.

*Better folks than I have used this, it seems.

*Compression: The squeezing force applied to a material. Most rocks resist compression pretty well. Sandstone, not so much.

*Tension: Pulling force. An individual rock has good strength in tension. A pile of rocks does not.

Posted in Basics, Building Science, Rot, Water | Tagged , , , , , , , | Leave a comment

The Holiday Season is Here

Thanksgiving morning and the local paper arrived at approximately 20 times its normal weight. The sales fliers will be recycled (in our house) or tossed in the trash. The next batch will arrive on Saturday and Sunday.

I was thinking about the cost and resources used to bring all this to my door and what I would like to see from stores this holiday season.  Using my awesomely nonexistent page design skills I made a display ad I’d like to see stores run in the papers instead of being inundated with glossy (and heavy!) inserts. If you happen to be the CEO of a store big or small and you’d like to use a version of this feel free. Consider it open source 🙂


2016-holiday-postIf you actually want a copy of this please let me know. WordPress limitations only let me publish this as an image. Suggestions for next year are welcome too.

Posted in Uncategorized | Tagged | 2 Comments

Oh, that’s gonna smell…

What is it?

What is it?


Sometimes you just get a lot of the same thing around the same time. The past couple of weeks it’s been the wrong way to insulate concrete walls. Out of the three instances recently, two were a bit, shall we say, aromatic. That’s a high percentage, but on those two I was called because of the odor. I think that increased the odds.

What is this dastardly method? Just the most common one. You frame a 2X4 wall as close to the concrete wall as you can get it, install fiberglass batts (other permeable insulation would work too), cover it with drywall and wait. If you can add an aquarium or a hot tub you won’t have to wait as long.

You could put a sheet of plastic under the drywall if you want to intensify things, too. That just slows down any drying potential. Remember, unless it’s perfect (really, really hard) plastic isn’t going to stop all the air from getting in.

Let’s look at the ingredients. We have a heated space (that’s why you insulated), warm air holds moisture better than warm air. We have a high mass (concrete) wall that’s relatively cool. Separating them we have an assembly that only slightly slows air movement. So the air in the room infiltrates the wall, condenses on the cool concrete and stays there. This is pretty much the recipe for mold growth. Whether you end up with a smelly mess depends on the amount of water and the speed of infiltration. If there is another place for the moist air to go more easily it will. Not to disparage air, but it always takes the path of least resistance.
Quiz time. Is the infrared image above one of the stinky walls or the non-stinky one. Hints: The darker colors are cooler. The studs have a lower R-value than the insulation. Water has a lower R-value than wood.





Time’s up! This wall does NOT stink. It’s not that wet. Check the temperature spread on the right of the image. The total range is just over 5F. Not very large given the temperature difference between inside and out, which was about 30F. The pattern shows some air infiltration at the top of the wall (the was no blower door, for you geeks) and a splotch in the middle that could be a compressed batt. So that was kind of a trick question.

But how do you make sure your wall won’t stink? Install rigid insulation* against the concrete. At least R-10, preferably double that. Then put 3/4” strapping over that, there are numerous attachment systems to fasten it to the wall, and screw the drywall to that. You’ll have to carve the electrical boxes into the foam (don’t overdo it) or use 2X stock on flat instead. Make sure that the seams are tight and tape them. Offset them too. No moisture is going to make it to the concrete, and the surface of the foam will almost certainly be above the dew point. No water, no smell*.


*I prefer XPS, but Polyisocyanurate will work too.

*Apologies to Bob Marley

Posted in Basics, Building Science, Energy, Water | Tagged , , , , , | Leave a comment

Short thought on a long sentence


Seaside cottage

Seaside cottage

“Where a preservationist might insist that broad expanses of decayed original plaster be repaired or restored with new material mixed and applied according to traditional recipes and finishes, a renovator would more than likely remove the plaster entirely, replacing it with modern materials that would more or less duplicate the original texture”. With one, long, sentence, George Nash* explains the challenge of old homes.

When you’re trying to save them from water damage and make houses comfortable, energy efficient and healthy for our modern times you have to understand the materials that are there, and how they behave. A section of board sheathing replaced with modern OSB can change the drying behavior of a wall in a big way. Add a rubble foundation with a heavy moisture load, and probably radon, and you can turn a house into a nightmare quickly.

With an older home you have to think about source control of water and air as the basic elements of moving a building into the future. If we don’t get the basics right we will lose many of our wonderful older buildings to our own thoughtlessness.



* Renovating Old Homes by George Nash. Published 1992 by The Taunton Press

Posted in Basics, Building Science, Water | Tagged , , , | 1 Comment

Skepticism as a tool


The other day a new IAQ (Indoor Air Quality) product assessment tool was announced by Healthy Building Network and Google. For building professionals this could be a valuable tool in their kit. We need to have access to good information on the products we specify if we hope to have buildings perform as we want.

What am I skeptical about? The narrow focus of this tool. There aren’t similar tools that examine the other aspects of the same materials. That could well give this tool more influence on the process than it deserves.

Suppose you’re selecting an interior wall finish material. There are several that met your general criteria, each with slightly different moisture diffusion characteristics. You run them through the IAQ tool and one comes back ranked better than the others. That’s the one to choose, right?

Maybe not. What if that product would cause excessive moisture accumulation in the wall cavity? You might cause a major IAQ problem trying to avoid a minor one.

Presumably, someone on the team would pick up on that. But these tools often tend to carry a lot of influence. And there may be an owner who decides that the tool rules, no matter what. There’s something very seductive about getting an answer from a computer. It’s precise, it doesn’t equivocate, no doubts.

Every method we use for choosing among options has flaws. But applying a bit of judgment and experience usually helps.

Posted in Basics, Building Science, Software, Tools | Tagged , , | Leave a comment

Don’t be a dim bulb

Photo of bulb by Jan-Erik Finnberg from flickr.com, used under a creative commons license

Photo of bulb by Jan-Erik Finnberg from flickr.com, used under a creative commons license


Light bulbs come up all the time when talking about energy efficiency. One comment I hear all the time, “I’ll switch to the more energy efficient bulbs as I use up the old ones.”

I’ve got a better idea, toss all the old ones you have and buy the most energy efficient bulb for your fixtures.

People who know me are aghast. I’m cheap and don’t like to waste anything. Throw out a perfectly good light bulb? I must have hit my head.

Don’t worry, frugality reigns. Even if it’s still in the package you’re better off disposing of it properly and starting fresh. Let’s go to the spreadsheet.

Haha! Scared ya! No spreadsheet, just simple math. I happen to need a light that provides about 1100 lumens so I’m using that as the basis of my search.

Lowe’s came up first, so I’m shopping there. They have a 2 pack of 20 watt CFL’s for $6.49. These are rated at 1100 lumens at 20 watts, with an 8,000 hour rated life. Just what I’m looking for. Let’s say I’ve bought them and they’re on the shelf. I’m going to round the cost to 3.25 each and run these things for their 8,000-hour life span. According the the NH Office of Energy and Planning, as of this writing the average cost of a kWh of electricity is $0.1629.

Now some math. At 20 watts it will take 50 hours to burn 1 kWh (1,000 watts/hour) so over it’s lifetime this bulb will use 160 Kwh. So the operating cost is $26.54. The total lifetime cost is $29.79.

Wait. There’s an LED option that only uses 9.5 watts for an 1100 lumen output. It costs $12.98 so it’s a lot more up front, but it’s rated for a 25,000 hour life. This bulb will take 105.25 hours to use 1 Kwh. To do a fair comparison let’s look at the cost at 8,000 hours. It will use 76 kWh in that time. Operating cost will be $12.38. Add the purchase price and you come up with $25.36. You’re already $1.18 ahead if you ignore the purchase price of the CFL (you threw it away).

The LED is going to keep going though, to 25,000 hours. Your lifetime cost will be $38.69 for electricity and 12.98 purchase price for a $51.67 total. Your hourly cost is $0.002067, not bad.

The CFL hourly cost is $0.0037. Even with all the decimal points that’s a lot more, and my Yankee thriftiness remains intact.

Posted in Basics, Energy, Lighting | Tagged , , , | Leave a comment

About a Thousand Words

No, I’m not going that long. Today I’ve got pictures, just two.

Usually, the pictures I bring back from jobs are boring and quite inscrutable to people outside of the building science world. Like this one.


This is just a poor attempt at insulating an attic hatch. I’ll write about it one of these days. I take pictures like this because I’m trying to illustrate something. Usually they show a particular problem, a single fault that occurs when we do something dumb to a building.

Today I’ve got one that I think illustrates a fundamental problem that happens during the building process. I call it the “Somebody else’s problem” problem. Someone does something wrong, the next person comes along, and instead of getting it fixed, says, “Not my problem” (NMP and SEP are identical twins) and covers over the problem, making it highly unlikely it will ever get fixed.

Often the SEP person has the excuse that he may not have recognized that there is a problem. But sometimes it is pretty obvious. Someone should have put a stop to things before they reached the level they did. And, on this particular occasion, I have to think that there was a little “Well, if you’re not gonna fix it I’m just going ahead. Deal with it.”

Yep, that’s a glowing bathtub. You’ve always wanted one, I’m sure. And why not? There aren’t that many.

I found this one morning doing a walk through inspection for a property management company. This is right off the landing of the second floor. I came up the stairs and stopped. (The glow was more impressive in person). It took a second to figure out what was going on. When I did I bolted down several flights of stairs and across a road to my truck. I didn’t have my camera. Doh! Unfortunately when I came back the glow was fainter (that’s a clue), but I got a half decent picture.

So what’s going on? Nope, not a nuclear dump. Although the glow is caused by a nuclear reaction, now that I think about it. Hint: It’s about 9:30 AM and I’m looking east. And I’m seeing sunlight. Someone put the bathtub over a window. Clever, no?

How the heck does something stupid like this happen? Well, this is a resort rental condo at one of New Hampshire’s many four season resort towns. When the plans were drawn up 5 bedroom rentals were fairly popular. But the market was changing and the “College Party” rentals were being supplanted by smaller, family-sized units. So a hasty redraw happened during construction (I’m engaging in some informed speculation on some of the details) to make two smaller units. As it happened the new location for the bathtub was where the window was. The window was there, nobody moved it. The plumber showed up to put the tub in, the window was there. The job superintendent was busy with something else. The plumber was under pressure to get everything done. Boom! One bathtub over a window. The Super was under pressure to finish, his boss was under pressure. It was “Somebody Else’s Problem”.

Let’s say you want to go skiing. It’s a great sport, but you live a three hour drive from this resort. You book a condo for your family. A nice one. It’s school vacation week. You pay almost $490.00 a night. That’s OK, you deserve a little luxury. After a great day on the slopes you want to shower before heading out for dinner. The bathroom is about 55 degrees even with the heater going full tilt. The tub feels like ice, but don’t worry, there’s no sense in getting into the tub, the pipes are frozen. Congratulations, you are somebody else.

Posted in Building Science | 2 Comments