Technical Bulletins

CRCA Technical Bulletins provide information on technical matters that have continuing, long-term impact on Canada’s roofing industry.

58 – July 2015
Roofing and Waterproofing Membranes

Although roofing and waterproofing are similar, there are important distinctions between them that must be considered by designers, architects and contractors.

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57 – November 2010
Photovoltaics in Roofing

As a result of the desire to achieve energy self-sufficiency with “clean energy”, solar energy production has increased an average of more than 20 percent each year since 2002, making it the world’s fastest-growing energy technology.

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56B – September 2006
Roof Gardens

The most important consideration when choosing which type of roof garden (intensive, semi-intensive, or extensive) will be built is the structural capacity of the deck.

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56A – October 2005
Roof Top Gardens: An Overview

Roof Top Gardens are becoming increasingly popular as building owners and managers strive to make new and existing buildings more environmentally advanced, energy efficient and sustainable.

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55 – September 2005
Roofing and Firewalls

Firewalls are interior walls that provide fire separation between areas of the same building.

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54 – February 2004
Cold Adhesive Applied Modified Bitumen Membranes

Faced with the reluctance of insurers to provide coverage for roofing applications involving the use of open flame, there has been a renewed interest in cold applied roofing systems.

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53 – February 2003
Ventilation

Many houses and small buildings are constructed with a roof or attic space between the upper floor ceiling and the roof deck.

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52 – July 2002
Cant Strips

The CRCA Roofing Specification manual defines a cant strip as “…a strip of material of triangular section placed at the intersection of a roof deck with a higher wall or other vertical surface.”

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51 – June 2001
Night Roofing

Our society has come to depend on 24 hour industries. Medical, transportation, public utilities, and even production facilities are operating around the clock.

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50 – June 2001
Cover Boards

Across Canada and the United States, the incorporation of cover boards in low slope roofing applications is common practice.

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49 – May 2001
Polyisocyanurate Insulation

For many years the use of polyisocyanurate (polyiso) roof insulation has been widespread in the roofing industry across Canada and the United States.

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48 – June 1999
Roof Re-Covering – An Alternative?

In the past, when a roof had reached the end of its useful service life and was no longer economical to maintain or repair, building owners usually had no other alternative but to replace it.

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47 – November 1998
Methods for Determining Moisture in Roofing Materials

key words: capillarity, dry range moisture content, equilibrium moisture content, gravimetric, hygroscopicity, thermal resistance ratio, wet range moisture content.

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46 – July 1996
Blistering in Built -Up Roofs

Blistering is a common problem with field applied exterior coatings such as paints and built-up roofing systems.

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45A – July 2008
Chemical Resistance of Roofing Asphalt

Since the discovery of natural asphalt deposits more than 5,000 years ago, asphalt has proved to be one of nature’s most useful – and abundant – materials. It has been used successfully as an excellent natural preservative, as well as an outstanding waterproofing and adhesive agent for centuries.

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45 – July 1996
Chemical Resistance of Single Ply Membranes

The performance of a roofing membrane over the service life of a roof depends on many factors. In predicting performance, often the un-compromised laboratory physical properties of the roof membrane are used to determine suitability of the membrane for the roof.

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44A – July 1996
Roof Top Effluence Management

Roof top effluents may come in many forms. Roof top effluents are generally in a liquid or particulate state though not necessarily.

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44 – October 1995
Roof Top Equipment

Low slope roof assemblies provide the primary function of separating the interior building environment from the outside elements.

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43B – July 1996
Application Guidelines for Torch Welding of Modified Bitumen Roll Roofing

Know the nature of the product you are going to torch such as thickness, reinforcement, under-face (sanded or thermofusible plastic film).

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43A – July 1996
Application Guidelines for Hot Asphalt Mopping of Modified Bitumen Roll Roofing

Modified Bitumen Roofing Membranes have been used successfully on numerous roofing projects throughout Canada.

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43 – October 1995
Wrinkling & Ridging of Modified Bitumen Membranes

Can roofs be “perfectly” constructed? Under most circumstances, the answer to that question would be no.

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42 – February 1995
Roof Joints

The effects of temperature, moisture, wind, seismic loads, and numerous other conditions can cause significant movement and dimensional changes in structures and their material components.

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41 – June 1994
Steel Deck and Fasteners Corrosion on Insulated Roofs

Steel decks in Canada have performed particularly well under all insulation boards because of the zinc alloy coating and extensive use of vapour retarders. Proactive roof maintenance programs are beneficial.

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40 – November 1993
Design of Loose-Laid Gravel Stone Ballasted Roofs

Roofing membranes have the potential for “wind uplift” if they are exposed to high pressure differentials above and below the membrane.

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39 – March 1993
Single-Ply Recommendations

The following are recommendations put forward by the CRCA Single-Ply Sub-committee reflecting the current state of the art in design and application.

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38 – March 1993
Fibreboard Overlays

Controversy has existed for some time regarding the application of hot applied roof systems over various insulation substrates.

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37 – March 1993
Fastening of Gypsum Boards to Steel Roof Deck

Gypsum boards are commonly used on steel roof decks for three main reasons.

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36 – December 1991
Awkward Roofs

In today’s urban environment, contractors are often asked to construct roof systems that they hope to never see again.

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35 – June 1988
Ballast For Protected Membrane Roofing

The Protected Membrane Roofing (PMR) has evolved considerably during the past twenty years and some of the changes involve the design of the ballast required to maintain the system in place.

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34 – June 1988
Control Flow Roof Drains Part 3

In June, 1969, the CRCA published a technical bulletin warning against the use of drains that are designed to retard the flow of water from the surface of a roof.

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33 – August 1986
Glass Fibre Roofing Felts – Special Application Techniques Are Required

The Canadian Roofing Contractors’ Association has recently completed an important revision of its Specification Manual.

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32 – April 1986
B.U.R. Membrane Application Over Urethane/Isocyanurate Insulation Products

The Roofing Insulation Committee of the Thermal Insulation Manufacturers Association (RIC/TIMA) U.S. have, during the last few years, conducted research as to why some roof membranes in a built-up roof system had a tendency to blister when applied directly over polyurethane/polyisocyanurate.

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31 – October 1985
B.U.R. Throughout The Years

B.U.R. consisting of several layers of bitumen soaked felt, bonded together on site with bitumen to form a continuous waterproofing membrane on near flat roofs, was developed near the end of the last century.

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30 – September 1984
Location of the Vapour Retarder In a Roof System When the Insulation is Mechanically Fastened

The role of a vapour retarder in a roof system is, as its name implies, to retard the entry of water vapours into the roof system.

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29 – June 1983
Building Slopes on Existing Roofs

For many years ponded water on so-called flat roofs has been identified as a major cause of premature deterioration of roofing membranes.

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28 – January 1983
Hot Asphalt and Built-up Roofing

Application of built-up roofing during cold weather has been a source of growing concern to the roofing industry for many years.

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27 – June 1981
Glaze Coating – Some Misconceptions

Good roofing practice requires that only as much membrane should be laid as can be covered with the final bitumen coating and aggregate surfacing during a normal daily working period.

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26 – November 1980
Sampling and Analysis of Bituminous Roofing Membranes

This bulletin supersedes all previously written or verbal statements by the Canadian Roofing Contractors’ Association on the subject.

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25 – October 1979
Non-Destructive Testing for Moisture in Bur Systems

There are presently three known non-destructive systems or test methods in use in Canada for the determination of moisture.

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24 – April 1979
PVC Roofing Membranes

One of the less desirable aspects in the promotion of new products is the undue emphasis placed upon any property that might raise that new product above competition or make it equal in that property to a competitor.

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23 – July 1976
Using the Protected Membrane System for Thermal Up-Grading

The first and most important step is to obtain professional assurance that the original structure will be strong enough to support the additional weight and that the building design will lend itself to the proposal.

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22 – April 1976
Effect Of Increased Thermal Resistance On Conventional Roofing Systems

The need to reduce operating costs and conserve energy is compelling owners and designers to reassess their traditional approach towards roof design with regards to the thermal performance of the system.

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21 – October 1975
Control Flow Drains

In June 1969, CRCA issued a technical bulletin stating, with reasons, that designers should avoid the use of flow retardant drains.

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20 – July 1975
Moulded, Preformed Flashing Systems

These systems consist of various assemblies of metal sections with and without flexible plastic sheet components.

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19 – August 1974
Roof Vents

When faced with a wet roof, it has been a common practice in recent years to install breather vents in an attempt to remove the moisture from the insulation.

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18 – February 1974
Sloped Roofs

Why do roofers almost universally recommend sloped roofs?

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17 – January 1973
Damage To Completed Roofs – Precautions Roofers Should Take

A traditional sore spot with the roofing contractor is that his newly applied roof immediately becomes a sidewalk for all.

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16 – August 1972
Respective Responsibilities of The Roofing Contractor, The Factory Mutual System and The Material Supplier In Specifications Containing Factory Mutual Requirements

Ever since the advent of Factory Mutual requirements in certain roofing specifications, some confusion has existed as to the respective responsibilities of the roofer, Factory Mutual and the material supplier.

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15 – April 1972
Effects Of Thermal Shrinkage On Built-Up Roofing

These are two organizations with which CRCA members are coming into increasing contact.

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14 – February 1972
Factory Mutual And Underwriters’ Laboratories

These are two organizations with which CRCA members are coming into increasing contact.

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13 – December 1971
Roofing Aggregates

Let’s be realistic about roofing gravel. Accept the fact that due to the small proportion of total production of the gravel industry consumed by roofing contractors, the roofing industry is in a weak position to demand what it may consider to be the ideal.

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12 – July 1971
Explanatory Notes on the CRCA Specification Manual

A roof exists for one reason – to keep the elements out of the building.

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11 – May 1971
Roof Mounted Equipment

The principle of the bituminous built-up roof is well over a hundred years old.

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10 – February 1971
Roofing Over Steel Decks

Roofing contractors, expected to supply a roof membrane of reasonable trouble free life, suggest that the steel deck construction industry in its competitiveness has passed the point of safety as far as the roof membrane is concerned.

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09 – January 1971
Upside Down Roofs

A roof system normally includes the following elements; a structural roof deck, an air-vapour barrier, insulation, and a water shedding or waterproof roofing.

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08 – October 1970
Exposure to Some Roofing Systems

We are enclosing a bulletin entitled the Exposure of some Roofing Systems. This bulletin was kindly made available to us by the National Research Council.

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07 – August 1970
Deflections

Many difficulties develop in buildings as the result of deflections of spanning members, which sometimes are in excess of those allowed for by designers.

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06 – July 1970
Confusion Concerning Insulated Steel Deck Constructions

What is commonly referred to as Class 1 Construction or Construction No. 1 indicates that these constructions have been examined by the engineering organizations working for the interested insurance companies and have met the requirements for spread of fire on the underside of the assembly and in some but not all cases for resistance to wind uplift.

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05 – May 1970
Conduit on Roof Decks

With the advent of post and beam or open ceiling structures the electrical conduit was often moved to the surface of the roof deck.

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04 – April 1970
Insulation

Insulations have been defined as the materials used to retard the passage of heat.

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03 – March 1970
Roof Maintenance

A roof is designed and expected to provide many years of service. However, it is often the most neglected part of the building – “out of sight, out of mind”, until it begins to leak.

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02 – February 1970
Water Vapour

Water can sometimes get into the wrong place in buildings as a gas, an invisible gas that can move through many building materials that may be impervious to water as a liquid.

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01 – January 1970
Ventilation Of Buildings To Prevent Damage To Roofing During The Cold Weather Months

During the cold weather months of October through April, immediate damage can be done to roofing on uncompleted or newly completed buildings due to the build-up of moisture vapour pressure within the building causing moisture vapour to migrate into the roofing system.

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October 1969
Winter Roofing

Built-up roofing assemblies are applied on jobs over a variety of substrates in all types of weather. Too often the roofing specifications are the bare minimum with design details favoring aesthetics at the expense of good roofing practice.

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September 1969
Expansion of Metals

available from which a designer might choose.

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May 1969
Common Technical Terms & Quantities Used In Calculating Insulation Values

During any technical discussion on roofing components or assemblies invariably certain technical terms, such as “K” factor “U” value, find their way into the discussion.

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June 1969
A Consideration of Flow Retardant Drains

One of the basic recommendations of good roofing practice promoted by C.R.C.A. since its formation in 1958, has been the advisability of draining roofs as quickly and as positively as possible.

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November 1969
Construction Conditions and Construction Water

Considerable information and thought are required to design a proper roofing systems.

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August 1969
R? U? Sufficient Insulation to Control Dew Point Temperature at Vapour Barrier

In our May, 1969, “Good Roofing” technical bulletin titled “Common Technical Terms and Quantities used in Calculating Insulation Values,” we listed certain terms and values in common use. Using that data, the intent of this bulletin is to put that information to practical use, in simplified form.

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December 1969
Corrosion of Metals

Corrosion denotes destruction of metal by chemical or electrochemical action.

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July 1969
Damage to Roofing Systems By Other Trades, The Consequences And The Cure

Corrosion denotes destruction of metal by chemical or electrochemical action. A gradual attack on the metal by its surroundings results in the conversion of the metal into an oxide, salt or some other compound.

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