Building Enclosure Consulting

Facade Doctor

Building Enclosure Commissioning

Building Enclosure Commissioning is the process of assuring the owner’s performance objectives are met.

Design Phase. We contribute our experience to peer reviews of construction documents. We review documentation for constructability, compliance with applicable codes and standards, and the current level of building science knowledge. We also produce technical building enclosure design drawings and specifications that become part of architectural construction documentation. Read more.

“Knuckle” connection of a faceted facade’s curtain wall transom integrated with a curved, shading “eyebrew,” which were hand-sketched by Kaz during discussions with the architect and prospective curtain wall providers. Architectural expression of the facade would be strongly influenced by the technical solutions supporting its curvature. Design Development of Leicester Theatre, Centre of Performance Art, United Kingdom, 2006. Rafael Vinoly Architects.

Typical Scope of Services:

  • Architectural design assistance and development,
  • Performance objectives development
  • Feasibility studies,
  • Specification writing and review,
  • Product evaluation and development,
  • Investigation of material and systems performance,
  • Development of LEED building envelope commissioning plan and specifications
  • Thermal, moisture, optical and structural analyses and simulations. Read more.
  • Education courses and workshops for architects and contractors

Download the printable scope of design services. (PDF, size 120 kB)

See our old and even older versions of this webpage.

Visual Air Barrier Testing

Air flow through building enclosures is supposed to be controlled. It typically follows that all exterior assemblies such as walls, roofs, and transitions need to be practically airtight, with exception of dedicated air vents. Lack of air tightness often may indicate other deficiencies: water leaks, water vapor convection, transmission of odors, insects, insufficient noise resistance, etc.

Air tightness verification requires two things: the differential air pressure and a tracer. The former is a prerequisite, and is unfortunately the most difficult to accomplish in field testing. We generate it by installing door fans, switching AC fans, and scaling down to specific location by building pressurized chambers, and sometimes, if we are lucky we got wind from just the right direction. The trace can be heat, smoke, trace gas, etc.

Beauty of the “Bubble Gun” test is that it’s portable, with the equipment very small, fitting the average carry-on case. The chamber is typically a small cone or dome made of transparent material (Some pros use acrylic or polycarbonate domes, I use a glass lid stolen from our kitchen, don’t tell my wife, she is still looking for it.) fit with a perimeter gasket, and a micromanometer gauge. The tracer is any sufficiently viscous liquid, preferably easily washable and compatible with the materials of the facade, such as soap water or dishwasher fluid (I happen to use a dedicated concentrated bubble solution).

Its testing procedure and equipment is described in ASTM E1186, among other things. After the chamber is sealed to the wall, air is pulled slowly enough to prevent bubbles from breaking (at the maximum rate 25Pa/sec). This kind of a very low vacuum is best controlled by slowly sucking air with one’s own lungs, but in the 21st century we use a portable vacuum pump. The rate of the vacuum buildup is controlled with a valve and a watch (there is also the bubble gun on the market with electronic controls, which is a nice tool, but seems to be an overkill for such a simple function). Soap water is spread on the wall in such a way as to not introduce any bubbles, but I haven’t found any better way for it than by a brush application, which always leaves some surface bubbles.

First bubbles are infused gases released from the thick soap solution, (just as they show up in a laminating resin when the vacuum is pulled) which we disregard, then the wall starts responding by releasing air through voids and imperfections. These bubbles are much larger and keep coming as the pressure is pulled, so it’s easy to tell them apart.

We mark these bubbles and we are done. It’s a practical “show and tell” test; the wall either passed or not. There is no way to measure the air tightness, because the allowable air flow would be below threshold of any gauge that I know about. If there is a bubble, it is reasonable to assume that the material/system would leak in excess of the 0.0004/0.004 cfm/ft2 thresholds.

Challenges. The testing is used to assess only the typical flat surface, as opposed to e.g. material transitions. The most typical testing cases would be a liquid-applied WRB, and these are often installed on very rough surfaces, which may successfully resist sealing the chamber’s perimeter, which in turn may need to be additionally sealed with some goop (e.g. chewing gum) or several additional hands pressing the perimeter gasket.

Practical considerations: The chamber is pressed against the wall by squeezing of the thick and very elastic perimeter gasket in order to seal the chamber to the wall. Any reversal of such a movement introduces large and abrupt pressure variations. Therefore, one needs to be careful not to accidentally release the chamber, as the vacuum increase caused by even a minute drop of hand pressure is far in excess of the standard-prescribed 25Pa/sec threshold, and may cause breaking of bubbles. Fortunately, the test can be repeated ad-infinitum.

Air pressures. Most barriers are rated at 75 Pa ( 1.57 psf ) which is useful for comparison among different materials and assemblies, but not so useful in individual cases. The typical wind pressures for low and mid rise buildings fall somewhere in 40 psf (1,915 Pa) range, while taller buildings or those located in coastal areas may easily see over 100 psf (4.788 Pa) of negative wind pressure.

Some installations are so bad that they do not need any testing. If the substrate is visible through gaps and voids, it’s a good indication that air would not stop just because your contractor said so. The prerequisite of all testing is to fix all conspicuous deficiencies first. Inexplicably, we would be asked to test them anyway.

Also, some building walls are built either without any dedicated weather resistive barrier (WRB) or they confusingly have two or more layers. The former is typical for thick concrete walls, which designers often believe that their thickness is a sufficient weather defense (as in the photo below, where heavy leaks were observed inside). Testing these walls may need a different technique, as the air pulled at such a crack can and probably comes from the adjacent crack, along the line of least resistance.

Tips and Tricks of The Trade. What is in your wall and roof and how to test it on your kitchen table? Best things in life are free. Kaz shares these tricks with designers and owners who are often unable to obtain physical characteristics of samples of brand new materials they consider using. In many cases all you need is a cup of hot beverage. 

This material republished here is brought to you by Building Enclosure Institute, the Florida Non Profit Corporation.

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Typical South Florida Wall

The typical thermal insulation that I see in brand new buildings in South Florida (hint: I only see sick buildings) consists of layers of paper or plastic film and aluminum film. It’s found behind the interior sheet rock. The thermal performance is very prone to field installation quality, and we saw large thermal discrepancies in the field. We collected several samples by tearing them off the wall here and there, and decided to see how they behave moisture-wise.
The manufacturer of the most commonly installed material of this kind has not shared the relevant testing reports with us, in spite of numerous requests over many years. Only the results are available.

We verified it the way we normally advise architects to test samples of interior materials: by placing it over your cup of hot beverage, and covering it with an empty cup.

It’s a quick test, as you would typically get results in less than a minute. It’s also scalable: if you have enough patience to measure the temperatures, time the test, and weight the collected condensate, you would obtain the exact permeability values, and if you repeat it several times to be sure, your numbers would be as good as those from the accredited/certified lab.

In most cases you would be testing unrated materials (e.g. good luck getting permeability number of an interior carpet from their supplier) that are intended for installation on the interior of the enclosure. If your carpet is intended on a floor over an unconditioned space, you’d need to select it coordinating with the other layers and climate: in Bahamas it needs to be permeable, not so much in Alaska.

One layer is covered with aluminum film. This thermal insulation is supposed to block thermal transmittance in radiant mode, which requires metallic surfaces for low emissivity.

The top cup remained clear. No surprises here: the aluminum film is vapor impermeable, just like an aluminum foil used to wrap meals in our kitchen won’t let any flavor to escape.
(We chose liquor glassed because its the most transparent, and otherwise the photo wouldn’t be clear enough, but you can use any vessels. And, no, we don’t drink at work.)

The other layer is made of paper, which is glossy on one side, as you can see here by the light reflection.

The top cup remains clear. This paper is also vapor impermeable, at least in the short term. The results so far confirm the permeability number given in its specification sheet: 0.018 perm (practically a vapor barrier).

Is it water permeable? We gave it a try, by cutting a circle, placing in a filter holder. Water dripped freely, even before pulling air from the flask below.

Conclusion: It could be a moisture trap. Per the manufacturer, this material was supposed to be installed continuously, fit snugly, stapled and taped tightly, without voids and interruptions (we have yet to see it installed that way). If this material were installed that way, it would block the inward vapor drive in hot and humid climate. However, since it’s typically installed improperly, we don’t see moisture damage behind it, but its thermal properties vary. But how many owners commission the building enclosures and order thermal studies of their houses?

So what’s in front of it? The outer layers of the typical wall we saw in front of it were either a cast-in place or a plastered masonry concrete wall.
(If you are unlucky, it’s a frame wall with a home wrapping paper around it, and if you are really unlucky, it’s EIFS.)
They are also typically void of any vapor barrier, much less any WRB (weather resistive barrier). Whenever I asked designers why, they typically responded that it’s enough that it was coated with elastomeric paint.

Concrete walls are also typically cracked, due to missing or inadequate differential movement compensation. (Want to embarrass an American architect? Ask them to draw your facade tectonics: the pattern of control and movement joints on elevations.) Cracks may differ from those visible across the street, to the invisible ones, for which one needs a bubble gun to find them. An elastomeric paints, regardless how many layers, won’t bridge those cracks. You would need a dedicated, thick “condom” (several dedicated products on the market, typically made with silicone) which we typically recommend to our clients for remediation of such hopeless cases; their cost is significant, and it’s definitely better to avoid the need for their use in the first place.

Here is the ASTM E1186 bubble gun testing of such a case, revealing air bubbling through a cracked bed joint of a CBS wall. (It’s coated with at least five layers of elastomeric latex paint.) Many buildings are like this, and historically it didn’t matter, because these are thick walls that were allowed to dry. However, circumstances changed: building interiors in the hot climate are now cooled, less vented, and interior layers of walls are impermeable more often than not. It should be no surprise that buildings also became sicker.

One of the manufacturers of this thermal insulation probably came to the same realization, and now they are also selling a perforated version of this material for those (probably rare) cases where it’s installed properly and moisture entrapment may become a problem. Perforations still don’t make it a good thermal insulator, unless it’s meticulously installed.
Bottom Line: It’s the cheapest rated thermal insulation that we know of. If you use it, you’d need a very anal retentive QAQC in the field, which would make it much more expensive. Otherwise, you may need to rip the walls open later just as we did when we got these samples.

Tips and Tricks of The Trade. What is in your wall and roof and how to test it on your kitchen table? Best things in life are free. Kaz shares these tricks with designers and owners who are often unable to obtain physical characteristics of samples of brand new materials they consider using. In many cases all you need is a cup of hot beverage.

This material republished here is brought to you by Building Enclosure Institute, the Florida Non Profit Corporation.

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Building Enclosure Commissioning at LaGuardia Airport

We have been involved in the $4B LaGuardia Airport project for over a year now. It’s a facility consisting of a central terminal building connected to two concourses via pedestrian bridges.

We were hired by the owner to screen its design and construction for conformance to the owner’s performance requirements. This process which is called building enclosure commissioning attempts to bridge the gap between a development and operations.  It assigns us role of guardians of quality on behalf of future facility maintenance and occupants. We verify various aspects of performance of the building skin, focusing on weather resistance, which is central to our practice. Kaz looks forward to the day, when he could land at LGA, and there would be nothing left for him to do, other than to admire the shiny new terminal with happy occupants in it.


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Building Enclosures’ Challenges Unique to Airports

Question I hear quite often: What kind of architecture do you do?  Building enclosures are fairly similar in all buildings, so my response often confuses and disappoints an interviewer, who expects an answer running along the divisions of residential, public, commercial, healthcare, etc.

However, upon reflection, building enclosures are not really similar in all buildings. Take airports for example; there are some challenges that are unique to airports. Large glazing ratios? Nope. They are common in other buildings as well, and not as spectacularly in defiance of the function of a building, as for example in a museum. Leaky roofs? Nope. They are also common to all projects in the U.S. except for the very few well designed roofs.  So, what is unique to airports? Here are two unique aspects:

1) Air tightness.

Can you recognize the sweet odor of  jet exhaust fumes? Suffocating, isn’t it? Air tightness is a common challenge at airports. Airports resemble Swiss cheese. The building is just a package for installations. The largest, most important, and awkward installation at any airport is luggage conveyors. Remember the time you were in such a hurry, that you checked your luggage at the curbside? It was sucked by the luggage conveyor into the building’s intestines together with exhaust fumes of your cab that was idling nearby, while the driver counted the change. Their serpentines penetrate the exterior building enclosure and interior mechanical zones with very large openings, which let air in and out, leading to energy losses and sucking contaminants and bugs in.

Another challenging area is the gates. Remember the feeling when you were late at the gate, and sadly looked at that closed door to the jet way? This door was the only door that was closed, and was only designed to stop passengers, not air. Regardless how the jet ways are configured, they all share one common characteristic: they are conveniently left open to the exterior by their designers and staff, even in defiance of security requirements. Remember when you were waiting in the long line in the jet way, and looked outside at the exterior stairs leading to the ramp open, where bunch of people in bright safety vest were struggling carrying strollers and gate-checked bags when overhead bins were full? Were you looking through an open side door? Well, this door was kept open by a door chock, which was placed there illegally by the ramp personnel, wasn’t it?

I will tell you a secret: next time you are looking for receptacle to plug your chargers in, just look behind the gate kiosk and sit down on the carpet nearby. Few people have a nerve to plug their laptop in the territory of the gate agent. However, the feeling you may notice instead of the adrenaline shot is the thermal discomfort. This is why the gate agent has her shawl and gloves handy, not just because she ventures through the jet way every once in a while. You may have enough time to look at the gate portal closely: can you see the moisture stains or a fresh paint? Align your eye along some straight line: do you see bowing? These are signs of moisture damage.

The reason is the interior door and the surrounding interior portal are, well, interior. They are not designed as exterior doors and portals should be. However, the average jet way is seldom the same mechanical zone as the building to which it is connected. It may be open to the exterior, air conditioned, or only heated. Often it’s left open to the exterior as described above, and therefore the interior gate portals become de facto exterior envelope. Which is why they sometimes show moisture damage caused by elevated humidity levels and condensation attacking the partition separating two different mechanical zones.

What gets tested gets done. Airports are seldom checked for air leakage, because they are typically interconnected with bridges, underpasses, and overpasses to other buildings, which would need to be plugged by temporary walls. Also, unless their own mechanical fans could be used for pressure testing, their volume exceeds the capacity of even the largest door blowers. Besides, by the time a contractor is done with the building enclosure, the airport is already long in operation.  Getting to the airside is a pain, due to security concerns, and coordinating aerial access even a larger challenge, so it’s only accessed once something conspicuously fails and needs to be fixed right away. After the cleanup, contractors collected their paychecks, management transition has already occurred, no one would endeavor to interrupt operations to conduct air testing. No one would even stick their nose outside. Which is why years later I would still discover unsealed joints and other construction defects, together with plywood sheets and buckets patiently waiting for a wind gust strong enough to be blown away and hit some aircraft or a ramp worker.

Add the inherent challenges of managing air changes at ports of entry due to the door traffic, and you can imagine how high the energy bills run. Imagine yourself getting a monthly utility bill much higher than your neighbor, whose house is smaller, older, and built with less insulation and less efficient HVAC system. You would probably investigate the reason, wouldn’t you?  It seldom happens in case of large buildings.  I often go to investigate such buildings and interview occupants, who are oblivious to spectacular water leaks, in spite of having worked there for years. No, they were not legally blind, only disinterested. Large buildings are often populated by disinterested occupants who feel disenfranchised from any ownership, and this attitude may be found surprisingly high in their management hierarchy.  Energy bills can be eventually passed onto and covered by somebody else, e.g. airlines and taxpayers, which is why nobody really cares.

2)  Noise Resistance.

Remember the last time you couldn’t figure out the gate change announcement? What is the new gate number? It was drowned in noise, wasn’t it? Were you able to finish a conversation, until this freaking airplane turned its engines off?  Insufficient noise resistance is a common challenge at airports, and is associated with high exterior noise levels generated by aircraft. My cheap aviation headset gives me 40dB noise attenuation, and this is more than the newly designed U.S. airport skin offers to its workers and passengers.

The typical airport is over glazed; glazing is expensive to begin with, and even more expensive to make soundproof. Perversely, this is good news, because it receives enough attention to be actually engineered and sometimes even tested. On the other side, all opaque walls are much cheaper and easier to make soundproof, and in most cases they would just need to be made heavy enough.  The old trick used by facade engineers in Europe is to add layers of cement board. That seldom happens in the U.S. Why? I get a blank look in response, when I flag it in the design stage. Architects in the U.S. for the last ten or so years finally learned how to tell heat bridging; however, they yet have to catch up with the rest of the world on the noise bridging and other aspects of building performance. It’s not something they are taught at college here.

Have you ever tried yodeling in an airport? Try it, when you are left in an empty airport after hours, like I sometimes am. The interiors spaces are huge and their significant volume exacerbates reverberation times. They could be designed for sound attenuation by choice of interior materials, but again they seldom are. The choice is typically left between materials within reach that are easy to maintain (hard, smooth surfaces almost invariably characterized by poor acoustic performance), and a painted gypsum board everywhere else. Have you noticed there is a carpet everywhere at many airports in the U.S.? You can test it with a cup of a decaf coffee, which is dyed with strong dark paint to resemble the actual coffee. Many carpets won’t survive such a test. Why would airports install something that is such a pain to maintain? And why airports abroad are not so often carpeted, with flooring surfaces ranging from stone to wood? I can only think of three reasons. Carpets become necessary, because of the poorer overall acoustical building performance, and because checked luggage allowance in the U.S. is so large that it’s typically rolled on a floor as opposed to carried in hand or over the shoulder like everywhere else. Rolling casters are noisy on hard surfaces, while rolling them on a carpet only causes fatigue. Also, have you ever slipped and fell on the hard surfaced floor? (The opening scene of my slip and fall in our commercial was filmed at the airport in Tampa after hours. And yes, I do all my stunts.). America is a highly litigious environment, which may explain the added cost of maintenance.

So, how do I respond to the question posed at the beginning ? My most typical response is that I only do high-rises, which is not true, but works well to fend off any looming requests to diagnose a pool or roof leak in a residential house of the asker.

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Energy Monitoring





ac pulse

This is the power measurement taken from a 3 ton central AC condenser in South Florida for one day. It’s a nice snapshot of an AC pulse, expressed in electrical current per time.

For mathematically challenged: after multiplying the number of amperes showed on the vertical axis by ~230 volts (not shown here), we arrive to approximately 3,200 Watts of power. This is equivalent of  320 led bulbs rated at 10W (equivalent of old incandescent 100W light bulbs). For comparison, there are 16 bulbs used to lit my house.

So, in other words, every time this unit goes off, we could just brightly lit 20 houses with the power used by this air conditioner, not counting the interior air handler which adds approximately 3 brightly lit houses.

If you read my recent post on HVAC zoning, you may now get the big picture: this single wall thermostat is not just turning a whole house on. It is akin to turning lights in 23 houses.

It’s responsible for ~1/3-1/4 of the total energy use in an old house with  uninsulated walls and windows, which in this particular case translates into approximately $700 a year.

It is also a good signature for health diagnosis of the system. Aging compressor? Inadequate refrigerant charge? It can be read between the lines.

How can you measure it? All it takes is a current transducer and a datalogger.  I am still paying off the loans which I took to purchase the professional equipment, but you can do it for much less. As I am slowly learning programming microprocessors, I discovered how relatively reliable and inexpensive became sensors which we can use for home monitoring: temperature, pressure, humidity, light, current, voltage, movement, smoke, water, CO2, and CO sensors to name a few. Most can be had for approximately $1 if one is patient enough to wait two weeks for them being shipped from China, and occasionally held by customs a little longer. These are good quality brands such as Bosch, and they can be installed redundant to reduce risk of defective ones.  Many come bundled, such as the temperature and humidity sensor I used in my experimental setup to drive a servomechanism of an AC diffuser.

current monitor

current monitor

Most residential dwellings are very similar in their functions, and can be sensorized, pre-wired, and programmed later with several repetitive options, as the total cost of materials would account for less than $100, with copper cables being the most expensive part. Commissioning would become a lifelong experience, all parameters would be continually monitored, and systems fine-tuned to achieve a comfortable and energy efficient configuration. Purchase decisions would become more educated, based on facts and hard data, as opposed to marketing claims.

Imagine, for example, that you live in this building in South Florida built recently and therefore thermally insulated. Your monthly electrical bill is twice your neighbor’s, and there are dark spots of microbial growth on AC registers. What would you do? I know people who spent thousands to get air samples collected and lab tested, and then  spent thousands more to litigate against contractors. Others may spending hundreds on a wireless, voice recognizing, smart thermostat system, or whatever else was marketed as a state of the art panaceum at the time. Unfortunately none of these would bring you closer to solve your existing problems.

However, with the monitoring,  all you would need to do is to have a look at your charts, or to program the software to issue reports of any irregularities and possible improvements. You would perhaps notice that the temperature sensors located in the forced air ducts show the supply air is repetitively below the adjacent ambient Dew Point, perhaps explaining those dark spots on your registers. High temperature readings in the attics may partially explain the irritating energy bill, and high humidity and low pressure readings coming from sensors on your exterior walls would explain the musty odor. What musty odor? You became too acquainted to notice it any more, and your guests are too nice to bring it to your attention.

So, how come every new house does NOT come fully equipped and pre-wired for automation?  Someone smarter must have figured it all out by now? However, if you look at the offering of the marketplace, it’s mostly irrelevant, unreliable, and self-contained. Congratulations, you can control lights in your dining room with a smartphone, and it only takes six or seven clicks, as opposed to simply flipping a wall switch. And you spent several hours with a customer’s support to troubleshoot the system and accomplish this admirable feat!

Houses don’t come pre-wired, and therefore smart home systems are designed and sold as wireless, which makes them fundamentally unreliable. If you live in a single family house like me,  you may not realize how literally crowded is the air. I didn’t, until I used my radio-controlled drone and a WiFi GoPro to remotely inspect exterior walls of a high-rise building. Two-way communication was lost in two floors height, roughly after 20 feet. A Wi-Fi replicator helped, but needed to be dropped on a rope to be approximately half-way between the observer and the device. These are challenges of wireless devices. Trust me, you don’t want to deal with them every day.

How do you wire a house with an existing forced air system? I just read a blog describing an admirable DIY method, which involved sending a parachute up the ductwork. The parachute was sent from the hood of an air handler, and it was made of a plastic shopping bag, pulling a fishing mono-filament, which was then used to pull the required 22 gauge cable for the servo controlling the register and for the psychrometric sensors. Whoever invented it was a genius. We need more of them.

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HVAC Zoning Considerations

If you live in America, you might have wondered why HVAC in your dwelling isn’t zoned. You can either turn it off or on, based on a single thermostat, in the most typical configuration. This is akin to having only one light  switch to turn lights on or off in the entire house. When compared to lighting, doesn’t it seem stupid and wasteful? Well, indeed it is.  Even if you live in a large house divided in several zones  by several air handlers, each zone would serve ~2,000 square feet give or take.

In fact, it’s even worse, as explained in my description of the energy monitoring. You turn on and off all lights in 20 houses, comparatively speaking. That’s how much more energy a typical air conditioner consumes.

Other continents are doing slightly better, mainly because their inventory of real estate is either older or designed by architects who never heard about forced air systems. There is no space for air ducts. Therefore, they typically install mini-split heat pumps, which individually distribute refrigerant to fancoils serving individual zones. Distribution is achieved by much more manageable 1/4″ and 3/8″ diameter copper tubing and wiring as opposed to insulated air ducts several inches in diameter. These mini splits are as expensive as they are efficient. Comparing the average mini-split to the average central air system popular in the U.S. made me gasp with astonishment, because the current draw was found to be many times lower, and comfort superior.


Back to America. If you stop by the typical HVAC supplier or a home improvement store and succumb to an overwhelming marketing, you may buy the state of the art learning touchscreen thermostat for several hundred dollars, only to discover that you are still turning the entire house on or off. So much for the promised energy savings.

The preferred solution would divide the dwelling unit into zones, which would be independently heated, cooled, and ventilated. To accomplish that, we would need to start with a system that, to my current knowledge, doesn’t exist on the market. We would begin with the ideal HVAC system described by John Straube, with a separately ducted ventilation, and have individual fancoil units with individually ducted returns.

How about retrofitting existing systems? Good luck with that. There are some interesting grassroots efforts of concerned citizens who discovered there is no commercial solution available, and decided to build one themselves, typically to remediate some extreme thermal discomfort resulting from an existing HVAC configuration.

The typical configuration would involve sensorizing individual zones and automating individual dampers or louvers of registers.

The solution typically involves an I/O board plus  temperature and humidity sensors installed in each zone and controlling servomechanisms modulating register’s louvers in those zones, and a relay board in lieu of the central thermostat. It would need to be driven by a microprocessor, like a dedicated stationary computer or Arduino board. A system like this can be controlled remotely by adding a radio, GSM, or Ethernet interface, with at least one dedicated Android app written and maintained by Mr. Vadim Tkachenko, a software engineer from Phoenix (why are Eastern Europeans so dominant on this scene, in a country of 300 million people, I cannot comprehend).

These systems should include ventilation; fresh air should be individually injected based on readings from individual CO2 sensors. It would also require pressure sensors to dynamically balance the system and for example ask for an air filter replacement. It would also need  dedicated dehumidification or humidification or both. Interesting addition would be energy monitoring using current transformers, which would also allow for early diagnosis of aging motors and compressors.I have not seen independent solutions like that yet, most likely due to the lack of professional involvement: based on my Internet research, home automation is typically attempted by individuals with programming skills and experience in robotics.

I read with interest some of these blogs and decided to try myself, as I am currently building my own house from a scratch.  Below is a picture of an experimental setup of a $5 floor register with a $10 servo and a $10 temperature and RH sensor controlled by a $40 Arduino board. I am learning C++ programming language as we speak, and find it quite challenging…



to be continued…

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UAV (Unmanned Aerial Vehicles) in services of the facade inspector.

Unmanned aerial vehicle can be used for facade inspections - Facade Doctor LLC

Unmanned aerial vehicle can be used for facade inspections.

Inspecting building facades is a risky business. I hang hundreds of feet above a ground on a rope thinner than my finger. Also, big overhangs and tall skylights are often not accessible at all. This is why I modified a popular remote-controlled toy drone to adapt it to the challenges of our trade. I have not heard of anyone else using unmanned aerial vehicles for forensic investigations of building enclosures, so i had to start from the scratch, by extending its range of flight, and adapting its sights.

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Tools of the Trade – Photographic Equipment

curtain wall anchor

Picture is worth a thousand words: a curtain wall anchor with twisted serrated washers. (Twisted washers don’t offer sufficient wind resistance).

Picture is worth a thousand words. A good picture can also save a lot of nerves. A good photo of a construction defect or a facade failure is self-explanatory and often cuts unnecessary disputes before they even start. This is why I consider a camera to be my primary tool of  the trade.

Apparently, the photos illustrating my field reports stand out on their own, because one of the most often asked question I hear is “how did you take this photo?”

Several clients asked my advice on buying the photographic equipment, and I thought is would be good to share pro publico bono the one I gave recently. Here it is, below.

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Thermal Stress Analysis

freeze-thaw failure of decorative rod connections on aluminum curtainwall facade

Freeze-thaw failure of decorative rod connections on a brand new aluminum curtainwall facade.  The  defect affected approximately 10,000 connections.

One of the chief reasons of weatherproofing failures of facades is the thermal stresses and associated movements in excess of  seals’ elastic capacity. This is particularly true for metal curtain walls, because of (Read the rest of this entry…)

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Tolerances and Inaccuracies in Concrete Construction

tolerances and inaccuracies in concrete construction

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Construction Phase – Consulting

construction consulting – BECx

We help contractors and owners identify unclear design intent requiring a request for information (RFI) and assist architects in responding to RFIs.  We have seen many disputes, and we can often help in their common-sense interpretation unclear language of specifications and contract drawings. You may be interested in Kaz’s old post about Spearin Doctrine.

The typical scope:

  • Bid and submittal reviews, substitution analyses,
  • RFI development and research
  • Waterproofing compatibility research
  • Proactive monitoring of construction in progress,
  • Witnessing QA and QC tests and verification of procedures,
  • Air, water, thermal, and structural testing,
  • Construction dispute resolution,
  • Commissioning of building enclosures (BECx)
  • Construction defect evaluation,
  • Negotiations with contractors,
  • Ownership transition (take-over) assessments,

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Computer Modeling and Simulations

3D thermal simulation of a skylight eave allows for verification of risk of frosting drainage paths.

3D thermal simulation of a skylight eave allows for verification of risk of frosting drainage paths. Skylight system designed, researched, engineered, and drafted by Kaz. Cleveland Museum of Art, Cleveland, OH, 2005

We assist designers  in verification of performance of bespoke components and assemblies via computerized finite element analysis (FEA): thermal, hygrothermal, optical, solar,  static, and dynamic. Many of these state-of-the-art computer generated analysis are unique worldwide. E.g., we are recognized as a world-class leader in the field of 3-dimensional computer simulations.

Download the printable scope of simulation services. (PDF, size 109 kB)

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Construction Phase – Monitoring


We collect data in the field, conduct field observations, perform quality tests, review submittals, and monitor construction in progress for conformance with the approved submittals and good industry practices. In the field, we provide standarized, traceable reporting, and periodically generate list of outstanding items. Construction progresses quickly, and nobody benefits from a report filed after the condition has been already concealed. Therefore, we exercise the proactive approach by informing the respective contractor about the discovered problem and offering assistance in developing mitigation plans.


Download the printable scope of construction services. (PDF, size 77 kB)

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Sloped Glazing Consulting

Sloped Glazing Leak

We specialize in the architectural glazing. Skylights and sloped glazing are the primary examples where the source of leak may be obvious; however, you still need an expert to identify the REASON of the leak and come up with a working remedial design….

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Curtain Wall Consulting – Design Phase

Measure Twice, Cut Once.

Measure Twice, Cut Once. The bespoke unitized curtain wall mullion intersection model built by Kaz for the UPenn Hospital project designed by Rafael Vinoly Architects.
The white extrusions were printed in 3D printer. The IGUs are the true low-E glass samples of the type chosen by the architect, courtessy of Guardian.

We established enviable reputation in curtain wall design and engineering. We analyze the architectural design against client’s performance objectives, and match with systems available on the markets. We also optimize an existing design or engineer a new system from a scratch if necessary to meet project requirements. (Read the rest of this entry…)

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Field Testing – Building Enclosure Commissioning

Field test following the AAMA 501.2

Field test following the AAMA 501.2 “Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls, and Sloped Glazing Systems” procedure.

We perform two types of building testing: in the real world and in the virtual world. For the latter, please see the our webpage dedicated to computer simulations. We perform and witness physical tests in the field to identify potential deficiencies and their sources. We normally follow procedures established by major industry associations and Florida Building Code. We also develop custom tests and modify the equipment to address specific field conditions.

The most typical tests include:

    • Thermal imaging of building envelope assemblies, by ASTM C 1060 “Standard Practice for Thermographic Inspection of Insulation Installations in Envelope Cavities of Frame Buildings,”

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Construction Phase – Consulting and Monitoring – Commissioning of Building Enclosures (BECx)

We collect data in the field, conduct field observations, perform quality tests, review submittals, and monitor construction in progress for conformance with the approved submittals and good industry practices. In the field, we provide standardized  traceable reporting, and periodically generate list of outstanding items.

Torched SBS roofing installation.

In the field, we provide standardized  traceable reporting, and periodically generates list of outstanding items. However, construction progresses quickly, and nobody benefits from a report filed after the condition has been already concealed. Therefore, we exercise the proactive approach by informing the respective sub-contractors about discovered problems and offering assistance in developing mitigation plans.

We also help contractors, and owners identify unclear design intent requiring a request for information (RFI) and assist architects in responding to RFIs. We analyse architectural specifications and offer advice regarding the contractual obligations and scope.  Kaz’s post about the Spearin Doctrine deals with some of these issues.

The typical scope:

  • Bid and submittal reviews, substitution analyses,
  • RFI development and research
  • Waterproofing compatibility research
  • Proactive monitoring of construction in progress,
  • Witnessing QA and QC tests and verification of procedures,
  • Air, water, thermal, and structural testing,
  • Construction dispute resolution,
  • Construction defect evaluation,
  • Negotiations with contractors,
  • Ownership transition (take-over) assessments,

Unitized curtain wall installation.

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What is a Building Consultant of the Building Envelope?

We tackled the question What Is The Building Envelope or Enclosure? in my other post.

Mur Vegetal - reintroduction of wildlife into the facade engineering.

Now it’s time for the General Description of the Profession.

Building facades are a very emotional subject – they are expressions of owners’ and architects’ individualities and become a lasting monument of their earthy achievements.

Facades account for up to 25% of the total construction cost and are the largest single determinant of a life building performance.

Their functions and construction are seldom fully understood by architects. By the end of the 20th century, high performance facades had become so complex that facade engineering began to gradually emerge as a specialized discipline.

However, façade engineering services are scarce in the U.S. and many architects are not even familiar with the concept.

Facade engineering is typically devoted to high-rise and high-end construction; one reason is the economical justification of the service, the other the scarcity of architects familiar with high-rise construction.

Facade engineering comprises all functions of the building shell holistically. The elementary function is to protect the occupants by controlling forces acting on building enclosures such as: rain, wind, snow, hail, flood, sun, light, wind borne debris, blast, heat flow, water vapor, wildlife, aggressive airborne and waterborne chemical, noise, vibrations, fire, smoke, theft, dirt accumulation, maintenance loads, and normal wear and tear.

They should be analyzed in conjunction with each other because all these factors overlap and intertwine. It naturally follows that it is a bad practice to analyze any of these facets in isolation from the others. A very frequent example is an unconditional endorsement of a plastic spray foam insulation by building enclosure consultants unaware of basic code requirements. As a consequence, their clients: owners and architects are required by municipal code inspectors to modify their buildings at a great expense.

Building Enclosure Councils are the first step in the direction of educating the general public about sciences and risks involved in building enclosures.

(The above description is partially quoted from “Facade Engineering. How To Design a Functional Building Enclosure” with permission of the author.)

Double-directional curvatures

Double-directional curvatures – sign of the old architectural trend becoming available to ordinary architects due to advanced parametrical computer modelingKaz worked on the schematic design and design development of the facade of the “walkie-talkie” buildng pictured in the center. London, UK.

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Design Phase of Building Enclosure Commissioning

Design Phase  of Building Enclosure Commissioning

Due to our European façade engineering roots, we offer a unique design service, assisting designers in pushing the edge as opposed to emphasizing limitations. It has a liberating effect on the architects, who can then concentrate on the higher-level tasks. We specialize in challenging high-rise and high-end structures, where the principles of science apply more spectacularly than in the low-rise development.

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Building Enclosure Commissioning Game – Construction in Field

As a recent economic refugee, I conduct periodic building enclosure construction observations in a field; the task normally delegated to junior employees.

The performance of the building is the contractors’ ultimate goal, or so they say. However, you may want to pay more attention to their actions.

Dismayed to realize what some construction managers suppose to be the truth about periodic building enclosure construction observations conducted by owners’ commissioning agents in the field, I have occasionally tried to show them the reality at personal expense. So here is the generic version, which hopefully would raise less anxiety and less pushback, as the readers would be sure to distance themselves from these circumstances described below. The circumstances described below are purely fictional.

Having seen the same scenario repeated dozens of times, I decided to put it on paper for benefit of those who are still trying: (Read the rest of this entry…)

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Value of Field Testing

Every now and then I get a call or email asking for clarification of a specified facade testing. It typically happens after a contractor had asked an architect to clarify the testing location to no avail, and the irritated owner got involved, while the construction of the assembly in question was already underway. After my short translation of the mysterious combinations of letters and digits, such as ASTM E 1105 or AAMA 501.2, into plain English, they invariably come up with the same follow up questions:

  1. Why should we test it in the field? Wasn’t it already tested in a lab?
  2. Where should we test? Why the architect did not show on drawings?
  3. We are already behind the schedule and above budget, is the testing really necessary?

1. The answer is (Read the rest of this entry…)

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