The beauty of this title given my article backlog is that I can publish it any time, even next year. It’s multi-purpose.

The folks at Maine Green Building Supply have been discussing the ‘Pretty Good House’ for several months now and I’ve had the chance to sit in on a few of those meetings. They’re good conversations and get at the heart of a central conundrum of efficient construction: How to balance sensible, cost-effective changes and make them as efficient as possible.

It got me thinking about how a ‘Pretty Good’ approach might apply to energy audits. While I have written a much longer post on the ‘Pretty Good Audit’, I thought I’d incorporate a few of those stray thoughts into a belated New Year’s resolutions.

A Belated Energy Auditor New Year’s Resolutions

Resolution #1: Don’t Fake Accuracy
I remember the first time I saw another company’s energy audit report. It was crammed with charts, graphs and impressive numeric projections. Of course, I immediately proceeded to rip off as many ideas as I could usefully cram into my own reports. As Bob Dylan said, Love and Theft.

One thing I clearly remember was that the payback period (Payback: the number of years until the efficiency upgrades would pay for itself) was reported to 3 decimal places like 11.271. Think about that for a moment. The audit wasn’t giving a range estimate like 10-12 years; it was saying TO THE HOUR when this improvement would pay for itself. That’s insane.

Using the above number, if installed on January 1st, this auditor’s report claimed that the improvement would pay for itself in 11 years on April 8th at 9:57 pm. That’s awfully accurate. Too accurate. No matter how well all the factors are accounted for, that exact a prediction would be impossible.

The first resolution is not faking accuracy. Overstating accuracy may make an audit feel more scientific and make the homeowner feel more confident in the recommendations. But those extra decimal places are crap.

Instead, recommit to the concepts of scientific precision and eschew the possibility of scientific accuracy. Precise means that the result is repeatable. When conducting the blower door tests, carefully document the building state (what doors are open/closed, the state of the building envelope, the weather, wind conditions) so that the test can be recreated. Do the same for CAZ testing.

Treat it with scientific rigor, as you would any formal measurement. It will improve your accuracy and your results. Just don’t fake hyper-accuracy for the sake of feeling like a scientist.

Resolution #2: 90% of Audits are Holes, Insulation and Safety
Energy audits involve a lot of testing. And given the expense, it’s tempting to defend the necessity of hours and hours spent poking holes into wall cavities or staring intently at blower door readings. But if I’m honest, 90% of what we do is fixing holes in the building enclosure, fixing insulation and ensuring homeowner safety, not discovering mysterious problems like some Sherlock Homes.

Holes – That’d be the Energy Star Thermal Bypass checklist. It details all the chronic holes in the building enclosure and how to seal them.

Insulation – Identify the insulation levels in the basement, walls and attics then improve them as viable to a sufficiently high level (Energy Star, Building Science’s 10/20/40/60, whatever high level you’d like).

Safety – Make sure that the is sufficient ventilation to meet ASHRAE 62.2 (adding mechanical ventilation), that there are CO monitors and that the heating system is either sealed combustion or adding make up air to atmospheric systems.

There are a lot more details like moisture levels and the unique information about each house. But the listed stuff could all be done without an audit. My next resolution is avoiding unnecessarily complicating audits. Stick to the basics of making the house warm, tight and safe.

Resolution #3: Stop Slagging On Fiberglass
My first energy audit instructor ripped on fiberglass insulation constantly. At the time, I knew a bit about cellulose but most of my installation experience was with fiberglass. I didn’t at the time grok the reason for the venom.

After seeing loads of installations where fiberglass wasn’t performing up to snuff, I began ripping on fiberglass too. In fact, my second or third post on this site was Why Doesn’t Fiberglass Insulation Work Well? I had become the grumpy old energy snob, looking down his nose at the insulation choice of amateurs.

In retrospect, it wasn’t the fault of fiberglass insulation. Rather folks would install the product, not understanding that a highly air permeable insulation like fiberglass needs to be carefully installed and paired with an air barrier.

My last New Year’s resolution is to stop ripping on fiberglass quite so much. It is inexpensive, doesn’t burn, can be installed by anyone with some attention to detail. Paired with ZIP walls or spray caulk, it can perform quite well.

Have a happy, precise and reasonably accurate, not overly complex and paired with an air barrier New Year!

Erik,

I have been trying to educate myself so that I may finish my house. I have a garage/basement that is above ground. Above that is the finished house. I want to fire safe my house, i.e.. separate the garage from the main house using 5/8 drywall in the ceiling. What I am not clear about, is what type of insulation to use, ( if any at all) so that the ceiling space does not trap moisture and become a mold source.

Secondly, should I proceed to insulate the basement walls, is it prudent to first seal the walls and floor with a concrete waterproofing such as Foundation Armor?

I have enjoyed your writings on the subject, and want to Thank You in advance for any advise you can give me.

DD

—– Original Message —–

From: Erik North
Subject: Re: Garage Ceiling Insulation

DD,

Sorry about the delay. I’ve been off my feet with a broken leg for the better part of a month and am just now catching up.

Thanks for writing. I get questions about mold a lot and there are some basic things to understand.

Mold needs a few conditions to grow. It needs food (as in plant cellulose like paper or wood), a moderate temperature (over 32 F) and high, sustained levels of moisture (over 50% RH and likely well over).

Mold has become a prominent concern over the last couple decades for a few reasons. One, the building materials we use, like OSB, plywood or engineered I-joists are highly processed wood products. They are chopped, mulched, chipped and formed into their final shape. Mold gets its teeth into these processed wood products much easier than a solid pine board.

Second, we engage in a lot more ‘water sports’ indoors than in the past. Hot showers for everyone, hot tubs, aquariums, indoor plants, etc. All these add a great deal to a house’s water load. Third, the building materials we use produce a tighter building envelope, meaning less drying potential.

Now granted, this doesn’t answer your question…it was more a chance for me to put down some thoughts about mold. The question to ask is: Is there so much moisture and humidity in your garage/finished room over the garage area that mold could be a concern? Is the humidity consistently over 60%?

In terms of insulation, if you are truly paranoid about mold growth, close cell spray foam would solve that issue. It would be entirely mold and moisture resistant. Otherwise, dense packing cellulose and finishing with drywall would work fine. Modern cellulose is treated with boric acid (or a comparable flame retardant anti-pest/anti-fungal agent) and the plywood flooring of the finished room would be sufficiently vapor permeable to allow some drying.

A more likely concern (but much less known) would that of carbon monoxide. After parking, car exhausts emit carbon monoxide for hours afterward. Make sure your drywall finish is a continuous air barrier, taping all seams and sealing around any penetrations. Also, have a carbon monoxide tester installed in the room over the garage.

On your second question, it is usually a good idea to water seal any exposed concrete. I recommend two applications of Drylok UGL. The only time this can be a problem is if there is enormous external water forcing its way inside. It would bubble up underneath the water seal.

Erik

—– Original Message —–

Subject: Re: Garage Ceiling Insulation

Erik,

Thanks very much for your reply. Breaking a leg is no fun. Wish you speedy recovery. Of course you may use this on your blog.

I found your comments about mold enlightening. So to better understand my application, I would like to give you more detail:

The home is built on a mountain ridge in Tennessee. Living space is raised 9 feet above unfinished basement with a concrete block enclosed walls with door and garage door openings. This space is an above ground basement. It has a fiber mixed concrete floor, 5000 psi, 4 inch minimum thickness, over heavy plastic sheet, 6 inches above grade. The ceiling above the concrete is manufactured I joist, 9-1/2 inches high with lots of plumbing and electrical wiring. This floor/ceiling consist of 3/4 inch Advan Tech subfloor, asphalt felt 15#, and 3/4 inch hardwood except in bathrooms where tile is installed. There is no active air seal on the sill plate or band joist from the interior. The sill plate has a sheet metal termite isolation between it and the concrete wall. Exterior walls are Advan Tech, house wrap and Hardy Board covering.

Peculiar to this location is high humidity. Winter temperature can get in the teens. Summer temperatures up to 100 degrees. The concrete floor is always very cold summer and winter. In the summer, basement doors must be keep closed to prevent sweating on the floors.

I am looking to solve two problems. First I want to fire isolate the basement space from above (using 5/8 drywall). As you mentioned, sealing the sheetrock will also reduce carbon monoxide exposure. That is where the question of insulating the floor/ceiling came about. Second I want eliminate air leaks and moisture in basement. Presently the dehumidifier controls a lot of moisture and runs a lot.

You recommended close cell spray foam for this application. Can this be done successfully with closed cell sheet foam attached to subfloor, or is spraying so much the superior method.? Or… would it be better to not insulate the floor/ceiling, just apply sheet rock and at a later date apply sheet foam to the basement walls and band board. Finally, if I do insulate the basement walls, should I insulate the basement floor.

I know I have lots of questions. There does not seem to be an industry consensus on this issue; hence my inquiry. Thanks again for your time. Your suggestions will be honored.

DD

—– Original Message —–

From: Erik North
Subject: Re: Garage Ceiling Insulation

DD,

First, I mistook this as a stand alone garage/finished room situation from the title. Now that you’ve detailed it, I realize it’s a more straightforward basement insulation/moisture mitigation where the garage is located on the basement level. My mistake.

Here are two good reference articles. The first details building an XPS insulated basement wall. In the second, it’s a similar approach with spray foam and butyl plastic as a floor cover.

http://www.homeconstructionimprovement.com/how-to-insulate-basement-walls/

http://www.buildingscience.com/documents/insights/bsi-041-rubble-foundations/

The idea is to basically create a styrofoam cup lining the inside of your basement. Conceptually, you’re using that styrofoam cup to keep the moisture out of the house. It involves a few steps, starting from the exterior and working in.

- Make sure the exterior drains very well. No areas around the house that pool water, no window wells that accumulate, gutters with 8+ foot water sluices directing water away from the foundation.

Everything on the exterior should drain away from the house.

- Install very good drainage below the flooring…Make sure that if you have water infiltration or moisture, that it will drain and dry.

- Apply 2 layers of Drylok UGL (again, just the brand I use) to all exposed concrete.

- Install 2″ XPS foam board on the floor and tape all seams.

- If you have a board formed or mold formed concrete foundation walls, XPS board can be used to insulate the walls. Otherwise, use closed cell spray foam. This would be applied from the sills to the foot of the walls.

- Install subfloor

- Frame up the exterior walls, either wood or steel studs. Add drywall to studs as an ignition barrier.

- Finish however you’d like.

I included a screen shot (for the email response) that pretty closely illustrates this approach. The only difference being that they re-poured a foundation floor.

Regarding the ceiling, now that I realize it’s a straight basement, I would just drywall but only after dealing with the moisture issues.

Hope that gives some conceptual guidance to insulating and addressing the moisture issues.

Erik

—– Original Message —–

Erik,

Thanks for your help. That is what I wanted to know.

DD

 
 
To recap: Last post I started reviewing possibly the worst house I ever audited. The house had built in 2008, which hit one of my pet peeves: That new automatically means good. But to reiterate a buddy’s favorite saying, “a house built to code is the worst house you’re legally allowed to build.”

An aside: A comment on the previous post mentioned that the building code covered a good deal of these issues years ago. I have to admit, I was being broadly harsh toward the building code when I had air leakage standards and thermal bypasses more specifically in mind. For example, Maine hasn’t adopted a statewide energy code as part of the building code. Both IECC 2009 and 2012 include air leakage standards, the testing of which would’ve revealed many of these issues.

The building: It was a 2008 ranch built into a hillside. It had an attached garage with a centrally located chimney, framed in between the garage and main house. An open concept kitchen was just off a cathedral ceiling great room that occupied a large chunk of the first floor plan. The master bedroom was over the garage. It was nice.

The Solutions

Moisture – One of the biggest challenges was tightening a building envelope with so much moisture. It’s a very bad sign when a house with a 6200 CFM50 blower door reading, flying through 1200-1500 gallons of oil each year is having mold problems.

Loads of energy pumped into a building enclosure and more air flow usually means more drying. If we just air sealed without any provisions for reducing moisture levels, the mold could potentially explode. It helps not at all to fix one problem and create another. This meant reducing moisture was the first priority.

Improving the exterior water management was tackled first (AKA getting rid of the pond in his front yard). Rainwater and snow melt was overwhelming the foundation’s existing footing drain so it needed some help. The plan was to do the exterior work first, give it a couple months and track the interior humidity levels. If they came down, great. If not, we may include some more interior moisture management.

The homeowner was fully committed to fixing all the existing problems so out came the back hoe. The contractor hired for the external water mitigation trenched down to the footer drain. We were pleasantly surprised to find the footer drain nicely wrapped in a drainage screen and relatively clear of muck and blockage. It was functioning; just being overwhelmed by the hill drainage’s massive water volume pressure.

The entire sub-grade hillside section of the foundation was coated with two layers of UGL Drylok. This concrete sealant is waterproof and vapor semi-impermeable, providing much more protection against infiltration that the bitumen damp-proofing.

Once the trench was filled back in, we landscaped the hillside ground, creating an aggressive drainage slope. About eight feet out from the house, leaving space for some landscaping later, we added a topside french drain. A 24″ trench was dug across, laid a perforated 4″ pipe at the bottom wrapped in drainage screen and filled with 1″ crushed gravel fill. Luckily, the hill provided a natural gravity drain out the sides.

Next was sealing the interior concrete. Normally, sealing concrete in high moisture situations may lead to upward capillary movement of the water. Not a worry here as the pressure treated sill plate was installed with a sill seal capillary break. The foundation floors were coated with 2 layers of Drylok. We left the walls alone, as we’d be applying closed cell spray foam later, itself a vapor barrier.

Next was evaluating the improvements. We left several humidistats throughout the basement and house and the homeowner checked them regularly, recording the relative humidity. Once we had a several weeks of data showing the humidity and moisture had come down (no more window condensation) we moved on to insulation and weatherization.

Time would prove that an extra step like adding an interior perimeter drain was not necessary.

Ventilation – Because we would be tightening the envelope up a great deal, we made provisions for combustion air for the heating system and a heat exchange ventilation system. One might not think that this house with its extreme air leakage would need mechanical ventilation. But we would be doing a lot of air sealing and more importantly would be sealing the entire ceiling, cutting off any stack effect driven air flow. Adding mechanical ventilation set to ASHRAE air flow standards made the most sense.

Air Sealing & Insulation – The Attic – One stroke of luck was that the cathedral ceiling was constructed of scissor trusses with enough space to work behind. This allowed easy access to the back of tongue and groove finish, the open chimney framing, the unsealed soffit vents, the recessed light canisters. All good news.

The existing fiberglass batts (two layers of crossed unfaced 9″ fiberglass batts) were pulled aside carefully. It was in good shape so would be retained and replaced.

The recessed lights were encapsulated with drywall boxes and caulked. The open chimney frames was covered with light gauge aluminum and sealed with high temperature caulk. The soffit vents were sealed with solid foam blocks flush against the exterior wall’s top plate and the existing foam proper vents. The top of the marriage wall between the garage and main house was sealed. Finally, 2 inches of closed cell spray foam was applied to the attic side of the cathedral ceiling and once cured, the fiberglass was replaced. After all the air sealing and insulation work completed, the blower door test out was 1925 CFM50. Not ridiculous tight but less than a third the initial reading.

Air Sealing & Insulation – The Basement – The basement/garage was next. I’ve never been a fan of defining the thermal enclosure at the garage door. The garage door is too difficult to insulate and air seal satisfactorily. The garage occupied the left hand third of the basement, under the master bedroom. A problem I forgot to mention last time was that the garage was plenty cold and the interior garage framing walls were open over their tops, with only cripple studs attached to the joists.

We pulled down a one foot strip of drywall and pulled out the fiberglass. I know we saved the fiberglass before but the garage ceiling was more problematic. From the exterior, the soffit vents on the cosmetic eave was blocked with foam blocking and sealed. The open space over the interior frame walls were blocked and sealed. Insulweb was tacked in over the gap in the drywall and densepacked in cellulose. We patched and mudded the drywall and all the cracks and penetrations were sealed with foam sealant and caulk.

Lastly, all the basement walls were sprayed with 2 inch closed cell foam and tumescent fire retardant paint.

Heating System – Not too much here. The single zone was woefully short in supplying heat uniformly. Rather than re-zone, we decided to see how the house would work after the weatherization effort. The homeowner added 2 inch closed cell foam pipe insulation to the entire hot water loop and other hot water pipes.

Problems Solved?

We checked back in periodically over the next couple years. The husband has been closely tracking the energy data or had been as of about a year ago. The heating bills were around 40% of their previous levels and the moisture issues have largely disappeared.

In the interim, the folks had gone ahead and re-zoned the heating system into three zones and added an outdoor reset. It was mostly happily ever after except for all the work need to arrive at that point.

I get a number of homeowner emails with residential energy questions. I try answer the questions and thought I’d publish (with permission) some of the responses here. I’ve altered the exchanges slightly to remove all personal and company names. I mean besides mine or those I’ve been involved with.

_______________________________________________________

Good afternoon Erik,

I am wondering if your company’s geographic area of work includes Central Mass, or if you have the name of a reputable audit firm that performs work in the Worcester area. I have read many of your pieces for Green Building Advisor, and am very impressed by your approach to energy issues in residential construction.

My wife and I purchased a post-war (c. 1949) cape in the fall of 2010. In the fall of 2011 into Jan 2012, we had dense-pack cellulose insulation blown in from the exterior.

Since that time, but especially this fall and winter, my wife has been complaining of allergy-like symptoms, to the point of asking me if we can have the insulation removed from the wall cavities. I have done some online research, and found a variety of thoughts on the topic, but I am wondering if there is any (simple) way of determining whether we may have the wall cavities inspected to determine if we have moisture / mold problems. In your experience, can this occur in the New England climate with dense-pack cellulose insulation.

Any direction or advice you may be able to give on this topic would be most appreciated!

L.K.

_______________________________________________________

L.K.,

I can speak to this directly, as I also live in a 40s era Cape which we insulated with dense pack cellulose.

First, I can’t say it isn’t possible that there are mold problems with the cellulose but it wouldn’t be my first thought. There could certainly be mold, other allergens or other air quality issues somewhere but mold growth in walls requires a few conditions.

For mold growth, you need a few things: Lots of moisture, moderate temperature (32 and up) and mold food, which is any organic material.

Mold doesn’t start growing with just a little humidity. It needs sustained periods of 50+% humidity and lots of readily available food. Why does bread mold up so fast? It is pure mold food with a high moisture content that we seal tight in a small, vapor impermeable bag.

Second, modern cellulose is heavily treated with boric acid (or something comparable). These additives are non-toxic and non-allergenic. They retard mold growth and makes it highly resistant to pests and fire. So its not like it is just shredded paper which would be highly susceptible to mold.

From my blog: What is Cellulose Insulation

Third, older buildings usually have wood planks for the exterior sheathing (if you have vinyl siding, peek under a seam to check). Wood planks have lots of leaky gaps where they butt up together. If you think about the thousands of linear board feet, it’s a lot of leaky cracks. The leaky cracks means more air flow, meaning the cellulose insulation drys out more easily.

These days, we build with OSB or plywood. They produce a much tighter building shell which means much less drying.

My experience insulating our house was that the cellulose produced a huge amount of dust infiltration. The cellulose came in every crack and hole and my dust allergy kicked up big time. We pursued an anti-allergen regimen (vigorously vacuuming, dusting, wet mopping under all the cracks near the walls) which alleviated my problems over a couple months.

Another clue to the problem would be that the problems flared up in the fall/winter. When we button down our houses, we’re also locking ourselves in with whatever air pollutants you may have. If problems persist (and not knowing how tight your house is), you could install a small HEPA-type air exchange system to provide continual fresh air during the winter months.

Erik

Erik North, Owner
Free Energy Maine, LLC

Last post I started reviewing possibly the worst house I ever audited. There have been others with a similar magnitude of issues. But this house had built in 2008, which some folks thinks signifies no worries. But to reiterate a buddy’s favorite saying, “a house built to code is the worst house you’re legally allowed to build.” It’s hard to make against dumb building.

To sum up: the house was a 2008 ranch built into a hillside. It had an attached garage with a centrally located chimney, framed in between the garage and main house. A open concept kitchen was just off a cathedral ceilinged great room that occupied a large chunk of the first floor plan. The master bedroom was over the garage. It was nice.

The Worst House I Ever Audited – The Problems

Moisture – The issues at hand were many … oh so many. First off, the moisture. The house had been built into a hill. Anyone who was done some landscaping can see where this is headed. The footprint was perpendicular to the foot of a long swale on the hillside, funneling massive amounts of spring thaw or rainwater down its three hundred foot long slope.

The hillside face of the house had a solid 40-foot-wide depression against the foot of the foundation. The owner confirmed that on rainy days that water pooled 4-6 inches deep against the building. Tens of thousands of pounds of water would flow downhill, where the inexorable pressure would force water through the porous concrete. The interior confirmed this, where in several places the concrete was damp to the touch.

This was causing huge problems in the house. The moisture was radiating from the foundation, condensing on windows and other cool surfaces. Bad, moldy news.

Foundation Heat Loss – The concrete foundation was a massive source of heat loss. The house, like I mentioned, was built into a hillside. In a past article, we talked about how concrete does a fantastic job holding a house up but a miserable job keeping heat in.

On the downhill face of the building, almost the entire foundation wall was exposed. Concrete has an R-value around 1 per 8 inches. So a 1-foot thick foundation wall would be around an R-1.5 (with variations for ash content, mixing in insulators like perlite, rocks, etc.) With a normal foundation, 18 or 24 inches may be over grade (above ground). The downhill facing of this house’s foundation was entirely exposed, it’s near 50 foot width showing from 4 to 8 feet above grade concrete. That R-1.5 mentioned earlier is close to that of a window. Imagine an almost 300 square foot window; that’s some serious heat loss.

Finished Room Over Garage – The finished room over the garage was something of a modern residential construction disaster. It was almost beautiful in it’s wrongness. A few years in hindsight, I still have trouble conceiving more things that could be wrong with a building built to code.

Where to begin? The master bedroom over the garage had a cathedral ceiling with tongue and groove finish. The cathedral ceiling extended to most of the first floor, and was perforated with recessed light cans.

The tongue and groove finish had no air barrier behind it. Between the tongue and groove finish boards and the leaky recessed light fixtures, stack effect driven air was flowing pretty unimpeded right out of the house.

Fiberglass batts were installed flush on the back of the T & G boards. When you lifted the batts, there were horizontal streaks were the glass fibers filtered out dust particles. The blower door test confirmed the visual evidence, registering 6200 CFM50 for a house a shade over 1600 square feet. For the non-blower door folks, that’s a monstrous number for a house that size.

The finish room over the garage was also compromised on most every side. This is easier to deal with as bullet points.

- The marriage wall was open and unsealed at the top, allowing warmed interior air to escape.
- The chimney was built into the house’s gable wall and framed in the finish room. The top was entirely open (like 2 or 3 square feet open), and I could see the garage floor down the shaft.
- The ceiling of the garage was thoroughly perforated and not remotely an intact air barrier. For example, the door opener brackets had been fastened to the garage ceiling joists and dry walled around. The holes were bad enough that you would see the underside of the finished room’s plywood flooring.
- Bonus time: the baseboard hot water pipes had been run through the garage ceiling.
- A pointless continuously perforated vented soffit ran along the garage ceiling/finished room floor edge. The contractor had tacked on an eave, a cosmetic detail added to create the impression of multiple floors. The soffit was open into the garage ceiling/finished room floor, venting air into the space. Awesome.
- The previously mentioned baseboard hot water pipes (now cool water pipes) are running right along this vented soffit. A hot water pipe less than 6 inches from an open soffit and cold winter air.

Needless to say, that was a pretty damn cold room.

Heating System – A brief bit on heating systems. Maine uses mostly oil. The rest of New England has a higher percentage of natural gas but Maine has oil. I’ve never heard a good reason why but I suspect it has to do with our strong rural population. It’s not terribly economical to run gas lines 15 miles to widely spaced towns of 1200.

In any case, oil. Oil heating means oil storage tanks and an exterior fill pipe and vent pipe for the tank. In every single house I’ve seen with a finished room over a garage, the oil pipes, tank and heating system are on the opposite side of the house. You can’t install them on the garage side; nowhere for the fill pipe.

The upshot is that the house’s boiler was installed on the far east side, opposite the garage. The heating system had one zone, covering the entire house. It ran clockwise, across the front, through the garage ceiling, past the open soffits and around the back side of the house before returning to the boiler.

So the hot water ran in uninsulated PEX pipes 6 inches from nearly 50 feet of uninsulated soffit and concrete foundation wall, 30 feet of soffits open to the outside air then another 50 feet of uninsulated concrete. Why were the north side rooms so cold? They had no sun and no heat was reaching them. Gah!

Next time…some solutions!

OK, maybe THAT house wasn’t built in 2008.

One thing apt to set my teeth on edge as an auditor is when folks casually assume that a new home won’t have energy problems or be inefficient. I was just discussing some marketing with a friend, who casually dropped that weatherization and efficiency work must have a great market in Maine’s old housing stock but would be pointless with new homes. *Commence ripping out hair*

The reality is the 99.99% of all homes can be substantially improved for efficiency and savings. And this absolutely, 100% includes houses built in the last 5 or 10 years. New means a great many things, but energy efficient is not necessarily one of them. Like an auditor friend says, “A house built to code is the worst house you’re legally allowed to build.”

The Worst House I Ever Audited (Was Built in 2008)

This leads us to the blue ribbon “Worst House I Ever Audited” which was built in … wait for it … 2008. OK, maybe I already blew the surprise. All eras of construction have issues and many, like minimum insulation levels, are ironed out by the building code. But some construction flaws are not yet addressed by building code or stem from a poor combination of building type and construction technique. And sometimes it all happens in one building at the same time.

The house was a 2008 ranch built into a hillside. It had an attached garage with a centrally located chimney. The garage was on the basement level with a driveway sculpted into the hill slope. The master bedroom was over the garage where the chimney was framed in between the garage and main house.

An open concept kitchen was just off a cathedral ceiling great room that occupied a large chunk of the floor plan. It had a lovely view with the surrounding hills framing it with autumnal foliage. The front of the house faced south, providing lovely evening sun. You could see why someone would buy it.

So What’s the Problem?

So, why did the homeowners call me? First, there were tremendous comfort and heating issues. Many of the rooms were uncomfortably cold and the heating bills were through the roof. The house had a clean north-south facing, meaning good sun on the south. But the north facing rooms were uniformly and brutally cold.

The basement was standard, modern slab and wall construction with formed, reinforced concrete. It was a thoroughly modern installation with capillary breaks, exterior bitumen damp-proofing and sub-slab capillary breaks (allegedly…no tools in the auditor’s bag to check that one). All that and the basement had huge humidity and moisture problems. There was evidence of standing water, flooding, sprawling, and efflorescence (evaporated mineral salts). The sill plate wood’s moisture content was in the high 30%s despite the capillary break and the basement’s relative humidity was a tick under 70% in March.

The finish room over the garage was frigid and the heating system was delivering very little heat to it. The finished room had an extended cathedral ceiling from the main living room.

And as a cherry on top, the homeowners were blowing through a roll of paper towels every other day. The humidity was condensing on many of the windows and left alone, starting to mold. See…it’s not just heating bills, it’s the hidden expenses.

Next time…the problems investigated.

OK, it’s been a few weeks but with good cause. I recently had a bad accident, breaking my ankle and right tibia. Granted that shouldn’t have affected my writing output but it is difficut to concentrate on other things when walking is suddenly out of the question.

Last post, we looked at the house I’d been investigating during my every first paid energy audit. Here we’ll look at the audit results, the recommendations and the final work that was performed.

My First Energy Audit – The Actual Audit

Maine State Housing Authority (MSHA) audits are intended to directly inform the contractor and their work scope so it involves a lot of measuring. These days I usually get a copy of the property’s tax assessor card to get all the dimenstions. For this house, we did a full schedule of all doors, windows, and dimensions, inside and out.

Looking back, the house was (and is) typical of the challenges with retrofitting older housing stock. Sometimes the building science, retrofit techniques available and older buildings don’t easy jibe. Most times this isn’t the case, and there are several companies (like our friends at Yankee Restoration) who specialize in older buildings. But it isn’t easy.

The Basement
Like I mentioned in the previous post, the foundation walls were double brick wall construction. The initial thought was spray foaming the walls, but this would prove difficult. A civil engineer with MSHA examined the structure and determined it wasn’t structural sound enough to spray foam (the load bearing wall was OK but the interior facade was crumbling in several places). Netting and densepacking cellulose in the basement ceiling was briefly discussed. However, the moisture from the sandy floor and standing water would’ve made a cellulose approach deeply problematic.

Mental note...Don't use cellulose down here

The Walls
The walls presented similar challenges. It was balloon framed construction with exterior clapboard. The cedar clapboard was original to the building, having been installed in the mid 19th century. At some point since installation, the exterior was coated with lead paint. The interior had a very thick plaster finish. So how do you insulate these uninsulated walls?

Like before, not easily. Traditionally, finished wall cavities are insulated by some manner of drilling and pumping in insulation. Without ruining the older siding or blasting lead paint dust everywhere (stripping off a course of siding and drilling or drilling right through the siding), it couldn’t be done from the outside.

An added wrinkle was that this house was in the county historical register. Any major alteration of the exterior was off the table. Even drilling through the siding, plugging and re-painting would’ve required approval.

The other possibility would be insulating from the interior. That would mean drilling holes for blowing cellulose through 1 or 2 inch thick horse hair plaster. This is not easy or pretty. Old plaster is like rock and just as hard to drill. Also, once the insulation is completed, it’s notoriously hard to hide/finish the drill holes. Contractors sometimes opt for a horizontal wood trim over trying to match the original plaster.

The Attic
The attic … the attic was in three sections, one each over the main house and two additions. Just about everything in the attic was open; the top of the exterior walls, interior walls, walk up stairways … all wide open. Oh, and uninsulated.

With older buildings, we often talk about insulating along the roof rafters. Air sealing along the attic flat in older houses can be difficult for a variety of reasons (settling of the foundation, access, extent of necessary air sealing). In this case, each of the three sections of the attic had widow’s peaks. It made air sealing the roof slope a much more difficult proposition as you’d need to tackle the ‘windows on all four sides’ widow’s peaks.

Blower Door
The blower door test came after the physical review and infrared scan of the house. After setting up, we fired the blower door up and witnessed air flying in from everywhere. The blower door read nearly 13000 CFM50 at -12 Pa. The blower door was moving several thousand cubic feet of air per minute and barely depressurizing the building.

Basically, every solid surface with the potential to leak air was doing so. Around doors, around windows, through the wall framing…like I said, basically everywhere. There was a huge amount of air sealing needed.

My First Energy Audit – The Work

Here’s where things get a bit disappointing. Maine State Housing’s low income weatherization program has set amount to spend per house, around $7000 in 2008. They can spend more but would need to pull money away from another project down the road.

It was determined that the house needed between $20k and $25k worth of work. MSHA can’t afford to commit three houses worth of efficiency work on one project so they were forced to move on.

It was an illustrating experience. I saw a spectrum of the issues that crop up with older houses, most of which I would see again. It also showed the limits of what was being done through public programs and the private sector.

I thought I’d start the new year by looking back: My first (paid) auditing gig.

My first energy audit was a few months after I’d completed Maine State Housing’s Auditor certification program. It was a two week program, one week of class work and one week of field training. Just enough learning to make you dangerous (and I’m only being a little facetious; uninformed auditor recommendations can have dire consequences). I had done three practice audits on the homes of friends and family and observed at three others. However, this was the first paying audit largely on my own.

I say largely because the audit was through MSHA’s low income weatherization program and one of their liaisons would be there. A little background … the low income weatherization program insulates and weatherizes homes of folks who qualify for heating assistance. MSHA evaluates the houses and tackles the ‘worst’ ones (those which use the most BTUs per square foot per heating degree day). Then they apply their limited budget to insulating and weatherization the building.

Eventually this program moved to the CAP (Community Action Program) agencies in the local counties. At the time, auditors evaluated the house and independent contractors bid on the work. The bit that probably got glossed over just now was the part about ‘the worst homes’ in Maine. That’s a bit unfair but they were terribly inefficient homes, as we would see.

My First Energy Audit – The House

The house I was assigned turned out to be a classic, very large 19th century farmhouse. It was located toward the end of one of the innumerable peninsulas that spike out from Maine’s coast. The Colonial farmhouse had a large main section and two enormous wing additions.

The first whiff we got that there would be issues was when the owner warned us about a rotten spot in the floorboards. “Careful with this spot; your foot will go right through.” A harbinger of things to come.

The foundation was double brick/rubble construction, with the brick wall above grade. The double brick wall (a two wall construction where the exterior wall is load bearing and there’s an insulating two-inch dead air space sandwiched with the interior wall). The interior brick wall was collapsed and crumpling in many places. The floor was wet sand with many pools of standing water, stretching into crawlspaces beneath the additions.

The windows and doors were almost all original to the building and loose would be an understatement. They were lovely, wood-framed single paned windows with sash weights…and the frames were so badly out of square I could often see outside around the frames.

The walls were balloon framed, the interior finished with old horse hair plaster and lathe while the exterior was finished with ancient clapboards coated thick with white lead paint.

The main house and two additions had distinct but connected attics. Each one was filled with various owner keepsakes nearly to the rafters. All told, a picturesque, full New England classic needing some TLC.

Next: the audit, recommendations and the work

Air seal! The most boring word and concept that can make all the difference in energy saving and comfort. Granted, I once said rising damp was the least interesting but important building science term, I think we can make a case for air sealing. Why is it important (and possibly more important) than just adding more insulation?

What Folks Think the Problem Is

When a house is cold and uncomfortable, the first thought is adding more insulation. This is a compelling thought for a few reasons. First, it’s a problem most homeowners can solve in a weekend. Assuming we’re talking about an open attic, a trip to the local big box for some rolls of fiberglass or a blower machine is all the solution needed.

Second, it’s a known and understood problem. The average homeowner may not have a clue about installing a fuse box or replacing the wax ring on a toilet but we all (we think) understand that more insulation = warmer.

This thinking causes a common issue: a fluffy pink fiberglass band-aid over a gaping wound that allowing heat to stream out. Folks pile on the insulation but haven’t air sealed. I’ll say this as clear as I can: Do not add more air permeable insulation until you air seal.

What The Problem Actually Is

The building enclosure has several control layers: the thermal layer (insulation), air and vapor controls. If there are paths for air to escape, your walls and ceiling are only doing a part of the job.

Attics have loads of little leaks (light fixtures, electrical penetrations, around vent fans) but sometimes have ridicously huge ones. Check out this photo.

Probably goes to the basement

The homeowners were complaining of a frigic second floor and didn’t understand given that they had a ton of fiberglass in the attic.

I had to pull back 18″ of crossed fiberglass batts to find this gaping hole. The house was built in 1797 with rough timber balloon framing. All of the interior and exterior walls were open at the top, allowing warm conditioned air to escape all winter. You could add R-100 insulation on top of the open cavity walls and it wouldn’t change things much. As long as there are giant holes in the attic floor, the insulation won’t work how you’d want.

Since then, the homeowners have had a contractor work through the attic, sealing the caps of the interior and exterior walls and all other penetrations through the ceiling plain. All the insulation was replaced afterward and owners reported it was waaaaay more comfortable. So remember to air seal then insulate.

 
 
 
This was a first. I’ve never seen dense pack cellulose in a basement. The sills had been netted and packed with cellulose. The netting and been pulled down in some places but the packed cellulose remained. This may not have been a problem if not for the surrounding swamp.

The house had essentially been built in a marsh. The moisture was saturating the foundation and wicking up into the sills. Lotsa moisture plus lotsa mold food (plant cellulose) equals lotsa mold. *Yech*

(Sorry about the dark photo…flash had died on the camera).

Homegrown Penicillin