An excerpt from a 1986 Canadian NRC “Building Science Insight” seminar titled Air Leakage Control. This seminar was put on across the country and cost $150 at the time …..very cheap for the # of $$$$$ it probably saved me then and makes me now!!
Consequences of an Ineffective Air Barrier System
The concept of the building envelope as an environmental separator was first promoted by Dr. Neil Hutcheon, former Director of the Division of Building Research, in a talk to the Engineering Institute of Canada in 1953. Dr. Hutcheon listed the principal requirements of the building envelope, so that each could be addressed separately and in conjunction with its counterparts. He noted that buildings envelopes had to be designed to control air flow and the moisture and energy flows associated with it. To quote from his talk:
“The flow of heat, moisture and air in walls have implications not only by themselves, but for all the other consderations listed. Air merits major consideration mainly because of its influence on heat and moisture flow.”
My comments: What we’re learning about today is not new!!! For some reason the building community never picked up on or didn’t care about informative sessions like these. When I attended this seminar in Moncton, New Brunswick, there were about 10-12 attendees- 5-6 from gov’t, 2 architects, couple of building inspectors and my business partner and I- no other contractors!!!
Comments from Gustav Handegord (NRC building science researcher and mentor to Joe Lstiburek) in 1998 address to the Alberta Building Envelope Council:
“It was once suggested that one problem in transferring technology in the building industry is that nobody reads anything. It may may be equally valid today since today’s practioners, as well as many researchers in building and construction seem to have neglected to read or re-read the Canadian Building Digests (free 3-4 page building science articles published monthly from 1960-1983 or so), even those that fall into their respective areas of interest.”
Those who frequent these threads regularly seem to be the exception to the rule. Looks good on you!!
p.s. The Canadian Building Digests are now online. Just do a search for them and a list comes up.
Edited 5/14/2006 1:32 pm ET by experienced
Edited 5/14/2006 1:36 pm ET by experienced
Replies
Perhaps I'm being overoptimistic, but I think the Internet may play a big role in disseminating proper building science. Look at how many times the buildingscience.com web site gets cited here. There is clearly a hunger for information, especially with escalating energy costs.
That's what Gus Handegord was hoping also!!!
Neil Hutcheon was the original developer of the system that later came to be called PERSIST. That is the system we use in which a rubberized asphalt membrane is used to cover the outside sheathing of a building and the insulation (2" of poyisocyanurate for example) is installed outboard of the membrane. This is the best possible wall system for IAQ and durability as well as being an outstanding performer in regards to energy efficiency. Lstiburek calls it the Perfect Wall. I call it the exterior air barrier system for constructing a high performance building envelope. Cudos also go to Chris Makepeace and Pierre-Michel Busque for strongly promoting it.
Met Chris Makepeace at the AGM of the Royal Architectural Institute here in 2001.(one of the two years I was fill-in lecturing at the local faculty of Architecture) An interesting and knowledgeable character.
Where can I find more info on this "Perfect Wall"? We are in the design stage of a new home and would like to investigate this more.
Jill
You can find good advice and poor advice on line.
I suspect the advice you promote is good for some locations and poor for other locations.
Always hire an engineer if you want a sutiable answer.
Not all engineers are created equal, either. Particularly for something out of the ordinary.
"Always hire an engineer if you want a sutiable answer."
From my experiences, I may have to disagree with this sentence. There may be certain engineers that have re-trained in building science on their own but they are scarce!
From my initial post:
"When I attended this seminar in Moncton, New Brunswick, there were about 10-12 attendees- 5-6 from gov't, 2 architects, couple of building inspectors and my business partner and I- no other contractors!!!"
Notice that there were no engineers at this very early building science seminar. At two others I was at prior to this, they were as well attended (LOL) and I don't remember any engineers!!!! The only engineering faculty in Nova Scotia still doesn't have an introductory building science course. (I know as I was in discussion with a professor there to help develop/deliver one, but nothing happening yet).
TRUE STORY:
A few months back, I got a call from the owner of a new slab-on-grade house with severe moisture, mould and odour problems. This house was known locally in the building industry and was quite visible in a web forum for a very popular Canadian TV building program. The builder (one of our biggest) will not accept any responsibility for the problems and has deep pockets!!
By the time, I was called, the problem was partially solved as she had hired a Phd. mycologist who found some vapour leakage areas and mould from a shower stall on an outside wall. A civil engineer had been brought in who told them to change grades around the house. From others advice, they then dug up along the slab supporting the 4' deep frost wall and drainage tiles and opened a hole low in the frost wall to let the soils under the slab drain bulk water outwards. This left some very wet/damp soils and straw that had been used to protect the footings that were poured in freezing weather. The straw was not removed from the excavation as it should've!!!
Since there was some air introduced after drainage of water, the straw deterioration by rot proceeded more rapidly with more odour coming into the house through hidden slab penetrations for services. The engineer (calling himself a building scientist) said to open some vent holes in the top of the foundation on opposite sides of the building (but this is full soil up to the bottom of the slab.....how will the ventilation really work?). On my later visit to the house, I mentioned depressurizing sub-slab for odour control as is done for radon control...... her response to me- "Why didn't the engineer mention that??"
At this point, she didn't want to spend any further money with me to design a sub-slab system (I don't have any degrees.....she wants degree types for a possible future law suit). The engineer's projected cost for a sub-slab system- $25,000 including design and installation.....ridiculous as this is a smallish house of about 2,000 sq ft in 2 stories; should've cost $5-6,000 at most!
So presently, she doesn't have a high opinion of "building scientists"......maybe that's why she hasn't hired me again.......or "But, oh, he doesn't have a degree so he can't be a building scientist,.... better stick with the engineer calling himself one" And this after having taught the Building Science course at the local Faculty of Architecture as a fill-in lecturer while the regular was at MIT doing his Phd.
So be careful of those calling themselves a building scientist. In Canada, there are no degrees available in the field yet. There is a certificate in building science available from the U. of Toronto which involves one day of classes per week over a full term (I believe).
What about the program at the University of Waterloo?
Couldn't find any building science degree program there although they have a "building engineering group" whose focus follows:
Our Research Focus
The current research focus is the hygrothermal performance (the control of heat, air, and moisture transport) of the building enclosure, innovative and advanced building materials, and interactions and optimization of the enclosure-HVAC package. We have unique strengths in full-scale field studies using test houses and field monitoring, as well as the use of computer models in the support of practical decision-making and product development
The present areas of interest include:
Energy efficient and sustainable buildings
driving rain and rain control, specifically drainage and storage in small gaps
drying of water retained after drainage has completed
the role of vapor barriers, inward drying, and solar driven condensation problems
wall ventilation drying, attic ventilation, crawlspace ventilation
house wraps and building paper,
hygrothermal computerized analysis,
pressure equalized rainscreens,
Insulated Concrete Forms (ICFs),
Exterior Insulated Finish Systems (EIFS),
climate sensitive building design,
Moisture and its effects on building performance is the key area of strength linking the above research topics. -END-
Sounds like most of the things we talk about here. There is a picture of the group with John Straube (another Joe Lstiburek type) heading the group. Appears he's the only one over 30!!
This is a post grad program in the school of civil engineering.
From the website of the University of Waterloo.
Structures, Mechanics and Construction Engineering
Major areas of study include:
applied mechanics
structural mechanics
steel and concrete structures
structural reliability
properties of materials
experimental mechanics
stochastic systems
builidng science
building performance
Current research activities include:
structural stability
static and dynamic response of structures
propagation of elastic disturbances in solids
stability of elastic and inelastic continua
structural response to random excitation
nonlinear stochastic processes
hydroelasticity
analysis and design of steel
reinforced concrete and prestressed concrete structures
building enclosure performance
structural optimization
conceptual design
computer-aided design of structures
strength and safety of structures
strength of pressure vessels
plastic behaviour of shells
mechanisms of fatigue failure in materials
structural model mechanics
experimental stress analysis
development of hybrid-experimental techniques for complex stress concentration regions
shape optimization
fluid flow theories and techniques of advanced experimental mechanics
principles of modelling reality
rheological responses of engineering materials
3-D mechanics of composite structures and of contact problems
fracture mechanics
optical methods in mechanics
isodyne and strain-gradient stress analysis
experimental testing of analytical models and solutions in mechanics
wall and roof performance
These courses are for Masters and beyond; not many practicing engineers get past the Bsc. program. And of course when you get into the masters and up, many tend learn more and more about less and less......getting down to being the world expert on one item!!!
You can get the odd "generalists" at this level like Joe and John whose interests in the field are actually a passion! My old gov dept has been bringing Joe in every 2 years or so since 1984-5 and John was here last year for the first time for the semi-annual 2 day "Enerhouse" Conference. From what I can deduce, Enerhouse would be similar to the EEBA "Affordable Comfort" in terms of level of professional training.
I still think that Waterloo lacks a good general "Building Science" program or area of concentration. Maybe they haven't developed one due to the fact that Toronto, 70-80 miles away, has one. Here's the link to the certificate program:
http://www.pdc.utoronto.ca/Page54.aspx
Edited 5/16/2006 2:58 pm ET by experienced