Looking at a complex relationship
By Cyrus Kabeer, CSP, NCARB, AIA, LEED AP
A senior architect tells the technician the deadline for issuing a package is next week; the firm has most of the drawings ready, but does not have the specifications. It contacts an independent spec writer who, of course, wants to keep this important client happy. The specifier temporarily puts aside all other jobs, and takes up the nearly impossible task, working 18-hour days to prepare the package. Unfortunately, the architect who has issued the working drawings/construction documents for bid does not have the time to read or co-ordinate the specifications; instead, the architectural specifications are issued as an addendum.
On seeing discrepancies and inconsistencies between the drawings and specifications, an opportunist contractor bids low and makes up the difference (plus a lot more) through change orders and extras. This eventually costs the owner much more than if the specification writer was involved from the beginning of the project and if the architect had planned for ample time to co-ordinate the construction documentation.
Does this sound familiar?
In more than one instance, this author has heard an architect tell a specifier something along the lines of “You want 250 hours for specifications? I have only budgeted 70 hours.” A project manager once told me, “We provide specifications only because the client requires us to do it—the contractor does not look at the specifications until there is a legal issue.” This is a dangerous line of thinking because it eventually has negative impact on the architectural firm and its reputation. I have seen requests for clarifications from subcontractors who constantly refer to the specifications before the bidding stage.
In my experience, very few architects get a specifier involved from the design phase. A specifier should be an integral part of the design team, helping in the preparation of Preliminary Project Descriptions (PPDs) and Outline Specifications.
Many factors come into play in deciding when to get the services of the specification writer, including:
- project size and complexity;
- use of innovative and specialized products; and
- whether the project or material used requires little or extensive research.
Provided the job captain has done adequate research on the materials and kept extensive records, the specification writer should be involved no later than when the working drawings are at a 40 per cent stage. This is when the architect has made major project decisions and the materials have been selected. In case a project is seeking certification under the Leadership in Energy and Environmental Design (LEED) program, the specifier should be involved immediately after the architect has decided on the LEED points to be pursued.
Qualifications of a specification writer
A specifier primarily communicates the construction documents in the written form to the contractor. A good specification writer is someone who:
- can interpret and understand graphic representation, schedules, and tables on drawings;
- has a good command of the language to describe the information in written words;
- offers good knowledge of construction materials, systems, and methods;
- has field experience and knowledge of how work is done onsite;
- can do proper due diligence in research;
- is organized;
- can manage time;
- has a fair knowledge of construction laws, applicable codes, standards, ordinances, bonds, and insurances in the construction industry; and
- boasts general knowledge of construction practices along with sustainability and LEED requirements.
The role of the specification writer differs from firm to firm to freelancer. For a small firm of less than 15 people, the principal or a senior architect may co-ordinate the specifications with an independent specifier, whereas medium-size firms may employ a full-time spec writer and larger practices may have separate specification departments. (Of course, any size of architectural firm may deploy the services of an independent specification writer at any time.)
What are the specifications?
Specifications go hand in hand with other construction documents, like working drawings and schedules. It may be in the form of notes on drawings for smaller projects to additional booklets in several volumes (i.e. Project Manual) for larger projects. A simple definition of the specifications is they are written descriptions that, in addition to the administrative requirement, describe the qualitative requirements of materials, product, workmanship, and services. Specifications are complementary to construction documents, and take precedence and supersede other documents.
A Project Manual includes procurement requirements in addition to specifications. These consist of contracting and bidding forms, standard conditions of contract, supplementary conditions, insurance requirements, and security and bonds. The procurement requirements should be prepared in co-ordination with the owner’s legal counsellor or attorney, the insurance agent, and the surety advisors.
Specifications may also include illustrations and the drawings. Graphics may be employed when it is difficult to describe the product in text and written description may cause misunderstandings.
Irrespective of when a specification writer is involved on the project, the architect or job captain should keep a folder and file catalogue cuts, information from websites, and memorandum notes in the appropriate divisions of MasterFormat, filing the minute notes separately. This information could save time and give a more co-ordinated construction document, as the specifier would know the product and the requirement of the design.
The architect’s contributions
During the schematic design phase of a project, the architect should describe the systems and assemblies for the project in the Primary Project Description—specifiers can use this as a reference while preparing the project specifications. The spec writer can also participate in the preparation of Outline Specifications identifying the materials to be used on the project.
Notwithstanding the specifier’s role, it is very important (especially at 60 and 90 per cent completion stages and just before final submission) a designated professional from the architect’s office proofreads the specification and co-ordinates the specifications of other disciplines, along with the full sets of drawings to avoid discrepancies.
This article, the first in a three-part series, aims to give the reader a general idea of specification writing. However, it does not offer a detailed explanation encompassing all aspects of the subject. Construction Specifications Canada (CSC), of course, offers several education opportunities and certification programs at the national and local chapter levels. This author strongly suggests architects who intend to write specifications check out the resources found at www.csc-dcc.ca.
Part 2 will examine language and specification format.
Cyrus Kabeer, CSP, NCARB, AIA, LEED AP, is an independent specification writer with an undergraduate degree in architecture and a master’s in urban planning, with over 35 years of experience. Now based in Vancouver, he has worked as an architect in the United States, Canada, the Middle East, and India, providing design, working drawings, specifications, and contract administration for institutional, transportation, industrial, military installations, commercial, and residential projects. Kabeer has been doing specifications since 2006, finding his passion for spec writing. He can be reached at firstname.lastname@example.org.
By Marco VanderMaas
What defines the contemporary home? Is it the compact condo? The McMansion? There seem to be two extremes, but not much in between when it comes to design. This is odd considering the variety of technology and materials architects and project teams have to build new homes and communities.
Diversity is often overlooked in today’s urban and suburban areas, but ‘missing-middle’ home typologies can restore the origins of city or rural living—where working and living is naturally combined, floorplans and spaces are flexible, and design and materials are human-scale and inviting. Missing-middle housing defines buildings and houses containing a range of different dwelling types, as well as live/work arrangements helping keep communities affordable, walkable, and vibrant. Typically, these buildings are larger than single-family homes and smaller than apartment buildings and high-rises.
Growing up in the Netherlands, this author lived directly above his parents’ retail store on a busy historical high street. A variety of housing options attracted diverse residents and allowed for an interesting and dynamic streetscape, giving the neighbourhood character and warmth. There, it was possible to complete most errands without having to ride in a car—but in Canada, the nearest schools and stores tend to be a long drive away from home, and windy, car-oriented roadways with large gravel shoulders, cracked asphalt edges, and potholes are the norm. Jumping on a bike or walking where you need to go is a challenge. How can a natural live/work experience be recreated in booming Canadian cities?
The future of city building with wood
Wood is one of Canada’s most-used renewable resources, and the country is leading the world in its use as a construction material. However, it is still possible to do more with wood. It may help to think of it as a crop that needs to be cultivated and harvested to feed growing cities.
After many years of protecting established neighbourhoods by way of zoning restrictions, municipalities are now seeing the opportunity to reverse these trends and make mixed-use timber-framed vibrant places a reality once again. The speed and scale of development in Canadian cities like Toronto and its outlying areas mean it is critical to be innovative with designs and construction materials. As community builders, design/construction professionals should be hyper-aware of shifting demographics. An aging baby boomer population, coupled with a mini millennial baby boom, necessitates very different approaches to architecture and construction. Consumers demand livable spaces and floorplans, flexibility, warmth, and green construction credentials.
Historically, wood has been associated with a cost-effective way of building safe housing and neighbourhoods, and that tradition should be continued. Wood construction allows homebuyers the opportunity to purchase a modern, spacious, and affordable home.
Wood is now a positively disruptive force in the construction industry, because it has been engineered to provide high-tech performance while maintaining its low-tech and more-familiar appeal. The material speeds up construction because it is relatively light and can be prefabricated offsite, but also easily transported to and assembled onsite. Quality, code-compliant, and safe structures can be realized by using a cost-effective and sustainable building material.
Taller wood structures can soar (take University of British Columbia’s [UBC’s] Brock Commons, an 18-storey student residence) or remain at modest heights while achieving high densities to present housing types people can identify with. They can have historical echoes, but are built with modern building codes and materials.
It takes knowledgeable architects and skilled construction crews to create taller wood buildings, but such construction is possible, and is resurrecting a far too long-neglected industry. Historically, wood is associated with structural members strong in the direction of the grain and weak in the cross direction. Wood is an orthotropic material, because properties change when measured from different directions.
New technology and engineered wood products have taken these properties and enhanced them. Carpentry and woodworking skills exist, and should be nurtured and grown by being infused with creativity and innovative supply-chain thinking. Carpentry should be one of the fastest-growing trades in Canada, as young people start to see it as an exciting viable career option infused with new technology.
There is also now the possibility for wood-frame ‘skyscrapers’ well beyond what current Canadian building codes allow. These have been embraced by many countries that never limited the use of wood in the first place. Of course, the limitations imposed on wood make sense, since many growing cities have experienced fires, which were devastating events that made way for urban renewal with measures of safety and new building techniques and materials to be introduced. Countries that did not suffer these fires have the advantage of being early adopters of this emerging way of using wood, potentially eclipsing existing Canadian expertise.
Mixing residential and office, or mercantile occupancy, is an additional benefit of these structures. Many established neighbourhoods have main streets with predominantly wood structures where this mixed occupancy is the norm, not the exception. These live-work typologies will alleviate some of the gridlock modern, single-use zoning regulations have imposed.
The opportunity to innovate with materials and technology is one of the reasons this author recently joined Q4 Architects, which pursues quality architectural design for municipalities and end-users driven by four principles: mixed-use, walkability, diversity, and density. Also critical are the four principles driving the construction industry: speed, ease, quality, and cost.
Regular dimensional lumber (i.e. 2×4, 6, 8, and 12) and engineered timber products (i.e. I-joists, laminated veneer lumber, parallel strand lumber, glulam, and cross-laminated timber [CLT]) are powerful building components. When combined with metal, hold-down straps, tie rods, and other hardware and fasteners, they result in extraordinary quality and cost-effective structures. These methods of mechanically combining materials are elemental, and are easily taught and understood. Comparatively, concrete and many more modern construction materials rely on chemical reactions and need certain environmental temperatures and conditions to produce the ideal results.
New back-to-back townhouse typologies this author’s firm calls intermediate or ‘i-rise’ housing provide options for people looking for affordable homes while complying with more sophisticated code requirements. Filling the gaps between low-, mid-, and high-rise, this housing type enables a fresh look at fitting together multiple livable floorplans, with accessibility and appropriate relationship to the street. Multi-unit living arrangements maintain building individuality while minimizing common space and amenity requirements of the more-typical double-loaded corridor apartment buildings.
These ‘missing middle’ wood-framed housing typologies give families housing options so they can enjoy access to retail, green space, and shopping. The lack of spacious backyards has brought more emphasis and purpose to pocket parks and the positive social benefits of public spaces, felt by young and old.
To allow taller structures by safely integrating renewable and combustible materials is to recognize innovations such as new structural mass timber products. Six storeys is just the first step to a more community-oriented and sustainable future. It is this author’s hope the new wood-frame building codes can be used to flex industry creativity for better and more-complete urban and suburban environments, allowing children of millennial families to experience what he did growing up: a healthy, safe, diverse, and active community.
Marco VanderMaas joined Q4 Architects as director of design in 2016, supporting his intense focus on mid-rise and new urbanism as well as his impressive track record in wood construction, utilizing the recent changes to the six-storey mid-rise wood-frame Ontario Building Code (OBC), and advocating for taller wood structures and new typologies. Passionate about understanding the power of design, VanderMaas does not shy away from embracing the architect’s role in complete community building. He can be reached at email@example.com.
By Carly Midgley
As methods of teaching, learning, and working continue to focus more sharply on collaborative, hands-on approaches, buildings must also adapt to support their modern occupants. An excellent example of this—the Columbus Centre/Villa Charities and Dante Alighieri Academy redevelopment project—is currently in the works at the Toronto nonprofit’s Dufferin Street and Lawrence Avenue campus.
This $60- to $70-million project consolidates the school’s 850 to 950 students within a single building and updates both school and community centre facilities, adding a wide range of shared-use spaces for students and patrons to draw on. In total, it will dedicate 11,173 m2 (120,265 sf) of space to Villa Charities programming, 14,279 m2 (153,698 sf) to Dante Alighieri programming, and 1374 m2 (14,789 sf) to shared infrastructure such as mechanical and electrical rooms. From a project team comprising CS&P Architects, Pillon Architect, Global Architects, and Gatzios Planning + Development Consultants, the new facility also maintains the existing centre’s focus on the Greater Toronto Area’s (GTA’s) vibrant Italian-Canadian community.
As the only North American project of this kind currently underway, the redevelopment requires some problem-solving from the team—for instance, in determining precisely how the joint-use arrangement will work.
“The joint-use operation agreement is a bit of a fluid agreement, because as the partners learn the building and learn to operate the building, they learn the best way to use those spaces,” said Maureen O’Shaughnessy, principal at CS&P Architects, as part of a presentation with Renzo Pillon (principal at Pillon Architect) in April. “I think they’ll grow into it, and the building is designed to allow them to grow into it.”
One significant addition in the new design is the arts wing. Funding limitations can often make it difficult for schools to provide spaces such as theatres, but Dante Alighieri’s partnership with the Columbus Centre means its students will have easy access to such facilities.
The new building will feature a 435-seat auditorium, which students and members of the community may use as need demands (such as for school productions or community events). The arts wing—described by Pillon as the “jewel of the building”—also contains music and fine arts studios, as well as four fully glazed, stage-sized dance studios. Overlooking Lawrence Avenue, these spaces’ clear glass walls provide a connection between the dancers and the wider community. The three-storey glass façade along the same street also provides daylighting capabilities.
Also included on a shared-use basis are areas for fitness, learning, and even cooking. A culinary studio features telecasting technology that can be used to connect students with instructors from around the world, while a triple gym allows space for both groups to get in shape. Yoga, aerobics, spin, and other fitness studios are available on the ground floor, with student use permitted at agreed-upon times each day.
Communal areas—such as a learning commons and a café area reminiscent of a traditional coffee shop—are promoted as study spaces, but classrooms are available to be used as well. These are designated for academy use during the school day, but open up for community programs (e.g. courses on heritage or English as a second language [ESL]) during off-hours.
Although much of the complex is designed to support the overall project goal of integration, the scope of certain areas (like the classrooms) is more limited. For example, the third floor is exclusively intended for school programming, while the fourth contains Dante Alighieri’s design suites and Villa Charities’ business offices. However, even these spaces are flexibly designed to allow for shared use if something changes in the future. Cross-corridor doors are employed to divide facility space, but can also be opened to allow the two groups to travel from one area to the other, if both parties agree.
The interior of the building is not the only area considered in this redesign. Outside, a new street—built to city standards for public streets—with a view of the new academy entrance will be constructed. According to O’Shaughnessy, encouraging use of public transit is one of the project goals, but the Toronto Transit Commission (TTC) has not indicated it will change its current pickup and drop-off point at nearby Dufferin and Lawrence to one on the campus itself. Nonetheless, the new street must be sized to accommodate fire-truck turnaround, and will therefore also be large enough to suit transit vehicles if the need ever arises.
Green space and inside/outside integration are prioritized on the building’s exterior, with such features planned as:
- vegetated roofs (over the triple gym, cafeteria, library, banquet hall, and student and community piazzas);
- an outdoor patio for the onsite restaurant; and
- a courtyard doubling as the roof of the theatre.
“One of the fun things about the outdoor space when you look at the model is the urban forest,” said O’Shaughnessy, referring to the greenery incorporated within the design. “The urban forest has an outdoor parkour kind of exercise equipment and the ability to circumnavigate the whole building—about half a kilometre—for an outdoor running/walking trail.”
Also impacting the exterior design is the ever-prevalent issue of parking. The centre’s communal spaces—such as the theatre, banquet hall, and gym—can contribute to high vehicular traffic, and the current parking offerings are inhibited by poor organization and the compounded effects of the facility’s gradual growth.
“This campus has definitely grown, and while at one point there were more tennis courts and whatnot, those were all eaten away with parking,” said O’Shaughnessy. “This tries to restore part of the character of the site and, again, build on those necessary pedestrian/vehicular links.”
To help maximize available space, Dante Alighieri’s designated parking area becomes joint-use after school hours. Further, to ensure the new centre’s parking facilities are shaped by actual user need rather than generic zoning requirements, a traffic consultant has been engaged to count cars and assess usage.
The design was updated following an open house with the Toronto Catholic District School Board (TCDSB) last month, when concern was expressed because no swimming pool was planned for the new facility. An 8.5 x 17.5-m (28 x 57-ft) pool with resistance jets has now been incorporated. Change facilities with private showers, sauna, and whirlpool are also planned, limited to Columbus Centre use. Some of the features in the current Dante and Columbus Centre facilities—such as racquet courts and a daycare—will be removed in the new development, although construction on a larger daycare is underway at the current high school site.
The existing centre will be vacated by the end of the year, with temporary facilities set to be occupied by January 2018. The demolition process—which will take two to four months—will begin in February, followed by a 24- to 30-month stretch of new construction work. No further construction is currently planned, but if any were to occur, it would likely be on the site of one of the existing parking lots, with an eye to preserving green space and further consolidating parking.
By uniting and organizing facilities and functions, the Columbus Centre/Villa Charities and Dante Alighieri Academy redevelopment project will enhance both bodies’ offerings and help make the most of available space in increasingly cramped Toronto. The planned facility stands as an example of the crucial role adaptability and collaboration will continue to play as the construction industry develops.
By Vrej-Armen Artinian, CSC, CSI
Every architect knows each new project and experience enrich our know-how, offering an edge on others who have not had the same opportunity to learn and advance. But how does this acquired expertise get integrated into your practice? There is no better place than your office master specifications (OMS) to absorb this new information into your professional system.
You may have ‘typical’ specs to use as the basis of your next project specifications, but how helpful are they if not continuously renewed and updated? It is easy to keep older construction documents, using them over and over again for projects of the same nature. However, this is exactly what I strongly advise against, even if for a consecutive phase for the same building. Things change, and what seemed right for yesterday’s project may not be suitable for today’s one.
Project specs do not constitute OMS. As their name suggests, they are project-specific, rather than general documents that can be applied to any job at any time. Are the National Master Specifications (NMS)—or similar commercially available spec compilations—good enough to be used as an OMS? The answer is both ‘yes’ and ‘no.’
NMS works well as a minimum basis to start a project spec, but it does not contain all the specific information needed to specify a certain product. This comes from your own input, and it can only be preserved if you keep your own OMS. (Further, since NMS and similar specs are updated periodically, basing your work on last year’s version may not be 100 per cent accurate for a new building.)
What to do?
Instead of putting down instructions on how to update specs, I will explain how I went through this endeavour to create a tool that now serves everyone in our office who puts together a project manual—in a very expedient and thorough manner—thereby saving time and money.
More than 25 years ago, when I started my new job as a spec writer (specs were typewritten at that time, if not handwritten first), I had a series of paper copies of project specs on my shelves. My first manual was put together with photocopied pages taken from several previous projects, with red annotations everywhere. Thankfully, computers came about just at the right time.
The first typeset project spec I produced, I decided to use as a basis to start an OMS. A copy of that spec was put aside, and when the second project spec was done, I introduced the new items into that first spec. Little by little, it started to grow; it now includes every new product or instruction that new projects brought.
Today, my OMS can provide 95 per cent of the contents of any project spec we have to produce. All articles and paragraphs not required for the new project are simply deleted, and the rest receives a little touchup here and there. Having to prepare specs in either French or English (or both for federal projects) means keeping current parallel series with exactly the same content.
Of course, compiling information and keeping them updated are two different things. It is not enough to add new materials, installation methods, or other requirements. Obsolete products must come out of your specs, while new or modified requirements need to replace old ones.
The first and easiest step in doing this involves comparing your OMS with the latest version of NMS, using its revisions as a guideline to revise your document. One must also take care to check against MasterFormat and SectionFormat/PageFormat since these CSC/CSI documents are also renewed from time to time.
The second step is to ask manufacturers to review your specs and suggest modifications due to product changes, the introduction of new offerings, or the addition of further information concerning installation. At this stage, you should also review the codes and standards mentioned in your document to ensure they correspond to the latest revised versions in force, as well as compliance of your text to them.
The third, and by far most important, step is to listen to your colleagues, project managers, and site supervisors when they come back with comments on what is written in your specification. This is the most valuable updating of your specs—that practical office experience specific to your firm and to the personnel whose collaboration you enjoy. Often, contractors can also contribute in setting straight your instructions and requirements since they are responsible for putting together and building what you are specifying. In the same manner, when two or more offices come together to form consortiums, they mutually enrich each other’s experience.
Finally, the last updating step comes down to you, the spec writer. You will always find an error, a typo, or something else to correct each time you reread your specs.
Updating specifications is no easy task. Keeping abreast of innovation and progress is challenging. While it may seem to be an expensive endeavour, it saves the office a lot of headaches in the long run, offering clients better service. In fact, with an updated OMS, the project spec is produced faster and with less effort.
I look forward to one day seeing an industry-wide updating process independent from manufacturers; one offered by a central body whose task is the common good and security of the users and the clients, private or public. With the proper funding, the National Research Council of Canada (NRC) could become that body, integrating that process into the production and revision of NMS and perhaps making it available to design/construction professionals at no charge.
In the meantime, it is up to each one of us to ensure our specs reflect the latest of our know-how and experience.
Vrej-Armen Artinian, CSC, CSI, is a graduate of Cairo University (B.Arch, 1964) and McGill University (M.Arch, 1969). He started his career specializing in the design of school buildings, then moved on to industrial buildings, laboratories, and research centres. Artinian has been a specification writer at Montréal-based NFOE since 1992. He is a member of Construction Specifications Canada (CSC), Ordre des architectes du Québec (OAQ), Construction Specifications Institute (CSI), Conseil du bâtiment durable du Canada (CBDCa) Section du Québec, and a Life Member of the Conseil de l’enveloppe du bâtiment du Québec (CEBQ). Artinian is also an award-winning contributor to the Armenian press in Canada. He can be contacted via e-mail at firstname.lastname@example.org.
By Art Fox
In masonry cavity walls—a design that has been in use for more than a century—the cavity provides a path for drainage and ventilation and acts as a capillary break. (The author would like to give special thanks to Steven Fechino [engineering and construction manager for Mortar Net Solutions], Jim Lucas of Lucas and Associates, and Scott Wylie of Wytech Building Envelope Solutions for their invaluable advice and expertise.) However, adhered masonry veneers like stucco have been installed for hundreds of years without drainage or ventilation. So why do we need to add drainage and ventilation planes to adhered masonry walls now? The short answer is American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings, and the Canadian equivalent, the National Energy Code for Buildings (NECB) 2011. (For more, read “The Sleeping Giant Awakes: NFPA 285.”)
ASHRAE is an international organization that sets energy-use standards for commercial buildings. Its standards are frequently used as the basis for building codes for jurisdictions in Canada and the United States. Recent changes in building materials, as well as increasingly strict energy codes derived from ASHRAE 90.1, have made drainage and ventilation for adhered masonry walls just as important as they are for masonry cavity walls. This article looks at how modern adhered masonry veneer walls are different from those built before the 1950s, and why these differences are making drainage and ventilation essential for excellent, sustainable performance.
The physics of water
Water molecules are attracted to each other, which results in surface tension—the skin-like film on the water’s surface that makes water drops possible. However, there is a limit to how many molecules can stick together before their weight or air movement overcomes the force of surface tension and pulls them apart. Molecular attraction also causes capillary action, which, combined with the tendency of water to move from wetter to drier, explains why a molecule of water entering a small hole will draw other molecules with it.
Large clumps of water molecules form liquid drops, which quickly run off smooth surfaces like stone and stucco, but will not penetrate an unbroken wall. If water gets behind the veneer, it also will not penetrate small holes in the weather-resistive barrier (WRB), such as those caused by the WRB and lath fasteners, because the attractive force of the water molecules toward each other keeps the drops larger than the holes. The weight of water alone is not enough to force it through.
That being said, when pressure differentials caused by wind-humidity differences or heat become strong enough, they can push the water through even very small holes. In building science, this is called hydrostatic pressure. It is similar to pushing a partially filled water balloon through a garden hose—it will not go through the hose by gravity alone, but put enough pressure behind it and it will. Additionally, if there is no bond break between the scratch coat and WRB, high moisture content in masonry will move to lower concentrations in the substrate.
So-called ‘perched’ water can also wreak havoc on adhered masonry walls with trim elements such as lintels. (More information is available in “BSI-057: Hockey Pucks and Hydrostatic Pressure,” by Joseph Lstiburek.) When water becomes trapped behind such walls in the narrow space between the trim and the veneer, it cannot drain due to the clumping effect of water-molecule attraction. The water then soaks into the masonry, substrate, or both. When the sun’s heat causes the humidity in the space between the veneer and WRB to become higher than outside or inside the building, the solar energy drives the moisture both outward through the masonry and inward through the WRB, as well as through any holes in the WRB and sheathing.
How water gets into the wall
Every mason and masonry wall designer knows water gets into masonry walls either as liquid (such as rain or snow) or as vapour (the gaseous form of water). Water vapour does not cause any trouble until it condenses and becomes liquid water. Therefore, providing a drainage mechanism for liquid water is vital, but it is just as important to get vapour out of the wall system before it becomes liquid.
Water penetrates the wall in three different ways. It can:
- enter as liquid or vapour through tiny mortar cracks or through gaps around wall penetrations and at places where different materials meet;
- be drawn as liquid by capillary action through porous masonry; or
- move as vapour from a warm, humid side of the wall to a cooler, drier side of the wall, where it can condense into liquid if dewpoint conditions are met.
In cool weather, water vapour can move from the warmer, more-humid conditioned air inside the building to the exterior, and in warm weather, it can move from the more-humid exterior toward the cooler, drier interior. In either case, the vapour can condense at the back of the veneer.