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Vanier, D. J.; Kyle, B. R.
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Canadian survey of low slope roofs: presentation of BELCAM data set
Vanier, D.J.; Kyle, B.R.
A version of this paper is published in / Une version de ce document se trouve dans : International Conference on Building Envelope Systems and Technologies (ICBEST)
2001, v. 2, pp. 427-431
www.nrc.ca/irc/ircpubs NRCC-44979
CANADIAN SURVEY OF LOW SLOPE ROOFS:
PRESENTATION OF BELCAM DATA SET
D.J. Vanier
1, B.R. Kyle
21 Institute for Research in Construction, National Research Council, Ottawa,
Canada. dana.vanier@nrc.ca Corresponding author
2 Technology Directorate, Public Works and Government Services Canada,
Ottawa, Canada. brian.kyle@pwgsc.gc.ca
ABSTRACT
This paper presents an overview of data for low slope roofs collected for the Building Envelope Life Cycle Asset Management (BELCAM) project. The data are from approximately 600 roofs from seven climatic regions across Canada. The data set consists of conventionally constructed built-up-roofs, modified bituminous roofs and a limited number of single-ply roofing systems. The roofs were surveyed from 1998 to 2000 using MicroROOFER for data collection. These data, collected by roofing experts primarily working for government or para-government organizations, are categorized by climatic region, roof age, condition, and membrane, flashing and insulation type. Regional breakdowns are also presented. These data provide a good representation of existing roofs managed by large building owners in Canada. This data set is used in BELCAM to calculate the remaining service life of low slope roofs.
1. INTRODUCTION
The Building Envelope Life Cycle Asset Management (BELCAM) project was co-founded by the Institute for Research in Construction of the National Research Council of Canada and the Technology Directorate of
Public Works and Government Services Canada. The intent of the project is to investigate and develop methodologies and tools to calculate the remaining service life of envelope components and systems with initial focus on low slope roofs [1]. Toward these objectives, roofs were surveyed from 1998 to
2000 using MicroROOFER for data collection. This paper provides an overview of data collected to date. The current data provide a good representation of existing roofs managed by large building owners in Canada. The BELCAM project will collect data for the next three years. This paper complements another paper in these proceedings [2] dealing with distresses found on the surveyed roofs.
1.1 MicroROOFER Data Collection
The BELCAM project uses MicroROOFER, a well-known roofing asset management tool, to collect data [3,4]. Many BELCAM survey sites use MicroROOFER as their "in-house" planning tool; however, the data transferred to the BELCAM national database are those data needed to develop the BELCAM service life prediction models [5]. Typically, the inspectors receive a day of MicroROOFER training that includes instructions on BELCAM Protocols, - extensions to MicroROOFER's standard data collection [6].
1.2 Data Transfer
MicroROOFER runs under Microsoft Access®. The BELCAM survey sites email their complete database file (*.mdb) annually to the authors and a macro, created in MS Access®, exports the required MS Access® data to a number of text files (*.txt). These files are imported into the BELCAM National Database, running on 4th Dimension®. These data include tombstone information (location, roof type, areas, roof and building age, sketches, CAD drawings, etc.) along with the condition data, distress type, distress severity, and distress quantity, as well as the condition of the membrane, insulation and flashings.
2. DATA ANALYSIS
Since the data collection tool is standardized (MicroROOFER, ver. 1.3), data from the survey sites are highly compatible. In total, data were received from across Canada, as shown in Figure 1. These data were analysed as seven climatic zones (One region has three
climatic zones, one with higher rainfall and one that is colder). The data are from roughly 600 buildings in approximately 15 cities or towns. Each building typically has a number of roof sections. In total, 13,267 individual visual distresses were identified, classified and quantified [2] on 3010 roof sections.
Figure 1. Map of BELCAM Regional Surveys
2.1 Regions
In Figure 2 the number of roof sections are shown versus the seven climatic regions. As can be seen, the numbers are well distributed across Canada; however, data are lacking in Regions C and D. More data from these regions will be obtained in upcoming years.
A B C E F G 800 D 700 600 500 400 300 200 100 0
Figure 2. Sections vs. Region
Figure 2 shows the full survey data. In some cases, baseline building data were entered but complete condition assessment was not performed (17% of low slope roof sections).
2.2 Membrane Type
This survey primarily includes roofs owned and operated by federal and provincial governments, crown corporations or publicly funded universities. The data in Figure 3 are representative of roofs in-situ for government-type organizations; however, they do not represent proportions for newly constructed
roofs [7]. Data in Figure 3 do not include high slope roofing systems (129 records).
BU R- N ot sp ec. BU R 3 p ly Mod . Bit Sing le p ly Unk now n BU R 5 p ly 1000 800 200 BU R 4 p ly Rol l Roo fing 400 600 1200 1400 0
Figure 3. Sections vs. Roof Type
2.3 Primary Flashing
Figure 4 show the different primary base flashings used. Mineral Surface flashings are
Glass, Organic or Unknown. Mod. Bit.
flashings are subdivided into Granule or
Smooth. Other flashings are those in small
numbers or where type was undefined.
EPD M Fibr egla ss Gla ss Oth er PVC Mineral Surface 1000 800 200 Met al Mod. Bit. 400 600 0 Org anic Unk now n Gra nule Smoo th
Figure 4. Sections vs. Flashing Type
2.4 Primary Insulation
Some roof sections have layers of different types of insulation; the types shown in Figure 5 represents the primary insulation recorded by the inspectors. The Other category consists of different insulation types in small numbers.
2.5 Age
As the BELCAM survey sites typically performed visual inspections on their total portfolio, the roof ages reflect the age of their
building stock as well as the extent of renewal. Figure 6 shows membrane age, but normally it is identical to flashing or insulation age.
Glas s Fib re None Phen olic Unkn own Woo d Fib reboa rd 500 400 100 Othe r Polyur etha ne B oard. 200 300 0 Polyi socyna urate Polys tyrene Expa nded Polys tyrene Ext rude d
Figure 5. Sections vs. Insulation Type
0-12.5 12.5-25. 25-37.5 37.5-50 50-62.5 62.5-75 800 700 600 500 400 300 200 100 0 1100 1000 900 Years
Figure 6. Sections vs. Age Classes
It must be kept in mind that the building owners in this survey are government or para-government organizations and, as such, are knowledgeable owners and try to optimize their life cycle costs for roofing maintenance.
2.6 Condition
Figures 7, 8 and 9 show assessed condition of the membrane (2363 sections), flashings (2363 sections) and insulation (324 sections), respectively. BELCAM State 7 is a roof that is excellent, whereas a State 1 roof must be replaced immediately [6]. The roofs in this sample are in good condition; this is indicative of the attention provided to the roofing portfolio by government-type organizations.
1 2 3 4 5 6 800 700 600 500 400 300 200 100 0 900 7
Figure 7. Sections vs. Membrane Condition
1 2 3 4 5 6 800 700 600 500 400 300 200 100 0 900 7 1000 1100
Figure 8. Sections vs. Flashing Condition
1 2 3 4 5 6 100 80 60 40 20 0 120 7 140 160 180 200 220
Figure 9. Sections vs. Insulation Condition The insulation condition in Figure 9 differs from the membrane and flashing condition. As mentioned earlier, a large number of visual inspections were performed in this regional survey; however, only 273 insulation inspections were carried out in the survey. This low number reflects the fact that although visual inspections were performed on most roofs in an owner's portfolio, the insulation inspections took place when the owner recognized moisture problems and called in specialty crews. As a result, the owners detect the problems, but also find the neighbouring
sections in excellent condition. This explains the increased number of poor sections (BELCAM States 1, 2, 3 and 4 in Figure 9).
2.7 Regional Breakdown
Figures 10 and 11 provide a regional breakdown. Figure 10 demonstrates the variability of age with respect to region (there are insignificant data for Regions B and C). In some cases, regional data are from one owner; therefore Figure 10 provides a roof age profile for that owner. For example, Region A has many newer roof sections; whereas Regions F and G have more old roofs in their portfolio.
200 100 0 300 A B E F G 400 0 - 12.5 12.5 - 25 25 - 37. 5 37.5 - 50 50 + Years
Figure 10. Sections vs. Age / Region
7 6 5 4 3 1 200 100 0 300 A B E F G 400 2
Figure 11. Sections vs. Condition / Region Figure 11 provides a regional breakdown for the membrane condition. Figure 10 can be juxtaposed with Figure 11 to show that Regions F and G are a portfolio of older roofs with the expected lower condition ratings. The
opposite is true for Region A: -- many roofs are younger and are in excellent condition.
3. DISCUSSION
The condition of the roof sections in this study is generally very good. As well, the high percentage at relatively young ages is an indication of a good renewal rate. This particular characteristic is believed to be a result of the high percentage of government and para-government ownership in the survey. The vast majority of sections in the survey were BUR or multi-layer application of modified bitumen membranes. While the population profile is representative of the typical Canadian situation, it does not reflect the membrane type profiles for new roofing construction [7]. In consideration of the industry’s increasing usage of thermoplastics (PVC & TPO) and the necessity to have reliable in-situ performance data, future BELCAM survey samples will include higher percentages of these membrane materials. These data show that base flashings are primarily organic mineral surface, not unexpected for the high proportion of BUR. A high percentage of roof sections were reportedly built with insulation of an unidentified or unknown type. This high population is attributed to inadequate effort in the gathering of the baseline roof data. The number of insulation inspections is low in comparison to that for membranes and flashings. This is due to the tendency to evaluate insulation condition when it is believed to be wet. As well, intrusive testing (insulation coring) to assess the condition rating is rarely seen as a desirable procedure
Future research affiliated with BELCAM will examine the correlation between visual inspection data and laboratory testing. This endeavor will increase the available samples and lead to refined statistical linkages between deterioration of membrane and insulation.
4. CONCLUSIONS
More roof data will be collected in the future by BELCAM project and affiliated programs. The current database provides a capability to assess a large data set and examine various aspects, on a population-wide basis, including regional differences in component condition, age distribution and material selection.
5. REFERENCES
[1] Vanier, D.J. and Lacasse, M.A. (1996) "BELCAM project: service life, durability and asset management research," 7th
DBMC (Stockholm), pp. 848-856, May.
[2] Kyle, B. R. and Vanier, D. J. (2001) "Canadian Survey of Low Slope Roofs: Profile of Roof Distresses", ICBEST, Ottawa, pp. 1-5, July.
[3] Bailey, D.M.; Brotherson, D.E.; Tobiasson, W. and Knehans, A. (1989)
ROOFER: An Engineered Management System for Bituminous Built-Up Roofs,
Technical Report M-90/04/ADA218529, US Army Construction Engineering Research Laboratory, Champaign, IL. [4] Vanier, D.J.; Doshi, H.; Kyle, B.R. and
Marcellus, R.W. (1998) "Maintenance software review: the art of roofing condition inspections," RCI Interface, March, pp. 10-14, 16-18, Mar.
[5] Lounis, Z.; Lacasse, M.A.; Vanier, D.J. and Kyle, B.R. (1998) "Towards standardization of service life prediction of roofing membranes," ASTM Special Tech.
Publication, 1349, Roofing Research and Standards Development, pp. 3-18.
[6] Lounis, Z.; Vanier, D.J.; Lacasse, M.A. and Kyle, B.R. (1999) "Decision-support system for service life asset management: the BELCAM project," 8th DBMC
(Vancouver), pp. 1223-1234.
[7] Canadian Roofing Contractors’ Association (1995) “Canadian Project Pinpoint- Roof Survey”, 6p., May.
