b'Winter RoofingManymembranesneedtobelaidoutinadvancetoproperlyIn these authors experience, the typical labour costs of a unionized roofing crew of six (within a 100-km relax before installation, and when membranes are colder, they become[60-mi] radius of home base) is in the range of $5,000 to $6,000 per day. Therefore, the question becomes, stiffer.Smooth-surfacedmembranesbecomedangerouslyslipperyShould the roofing crew remove some snow to do a little bit of roofing only to repeat the work a few days when wet or icy, a factor that must be considered for worker healthlater, after it snows again?and safety. Single-ply membranes may also be more prone to damageThis is a difficult decision to make. For example, if there is only a day or two left to complete the project, from shovelling snow. the team may consider spending this amount and finishing the work. Alternatively, if the team is about to start a new section, the work may be halted until the weather improves. Finally, depending on the project delivery schedule, operating requirements and budgeting limitations, the team may be forced to take the Weather least palatable option, which is to accept the risks and work through the winter.Understanding the weather conditions at the place of the work isRoofing work could also impact mechanical systems, which may need to be temporarily turned off to critical in deciding when to start or temporarily stop roofing opera- avoid drawing in odours and dust. Having the heating system down during below-freezing temperatures will tions. It can be a bit of a costly guessing game. During the winter,have a definite impact on occupant comfort. Usually, sequencing the downtime of units will be required or design/construction professionals are faced with prolonged periods oftemporary heat may be necessary to maintain interior comfort for tenants.rain, extreme cold, wet snow, ice and cold winds, which can pose aThese considerations must be made in the early stages of the project so adequate planning can be incor-significant challenge to the project schedule and budget, as well as theporated into the design.patience of all parties.Product manufacturers typically require underlying surfaces to beThe Human Factorfree of debris and moisture (e.g. water, frost, snow and ice). Who takesIt is cold, wet and slippery on the roof. During the cold months, light summer clothing is replaced with care of snow and ice removal prior to and during construction ac- the dreaded winter weight. For roofing crews, this means long underwear, heavy sweaters, winter jackets, tivities is a critical decision. Contractors must be allowed to properlydouble gloves, wool hats, heavy wool socks and more. This can represent an additional 13.6 kg (30 lbs.) of carry additional costs if this work is to be done by their forces. If snowclothing, significantly slowing down movement around the roof.removal is to be completed by the owners team, this poses additionalIrrespective of how well the crew is dressed, the cold plays a significant role in roofing as workers may challenges, as the owner may be deemed the constructor of the proj- face the risk of frostbite to fingers, toes, noses and earlobes, as well as hypothermia, when working in ect, meaning responsibility for site safety shifts from the contractor toextreme temperatures. According to the Canadian Center for Occupational Health and Safety (CCOHS), the owner. the risk of moderate frostbite can occur between a wind chill of -10 and -27 C (14 and -16.6 F). Figure 1 Contractors may dispose of a light amount of snow by either sweep- illustrates the exposure risk as it relates to ambient temperature and wind.ing or shovelling it away from the work area. If the building is non- In the preparation of the contract documents, consideration should be given to the question of whether combustible, they may decide to use an open-flame torch to meltthe crews can use the owners facility for warm breaks and storage or whether the contractor has to provide the snow/ice and dry the roof. Cleaning snow off a concrete deck isonsite heated storage containers.relatively easy, as it is just like shovelling the driveway, but on a steelWorking during the winter months can also impact crews overall productivity and the project schedule. deck, the contractor has to clean the lower flutes, which is an extremelyIn these authors experience, depending on the type of roof and rooftop equipment, production can de-tedious and time-consuming task that may take several hours to com- crease by 20 per cent or, in some instances, more. This can be attributed to the need for additional site/deck plete. Quality and durability issues can surface with the roof system ifpreparation, temporary heating, storage and additional material handling, as well as the weather, reducing the substrates are not adequately dried. For example, blisters may formworking time by up to six hours (Figure 2).or adhesion could be compromised. Snow removal is as expensive as it is labour intensive. It can take three or four roofers out of a typical six-person crew to undertake thisSchedule (Design/Tender and Construction)task, and more if the snowfall is heavy. If the requirements for snow management are not factored into the contract documents, then theContractors typically cannot start a project right away, and a properly designed and detailed new roof owner will likely be exposed to additional charges for snow removal. system is of the utmost importance. A key underlying factor in the preparation of a reroofing project is the development of the tender and design documents. During this process, the designer works closely with Figure 1 Image courtesy Environment Canada the owner to determine the best roof design for the building while meeting the owners requirements and project budget. For example, owners may restrict use of asphalt-based products or mechanical fasteners due to conduits or services on the underside of the deck. They may also have personal biases against specific assemblies and manufacturers they do not wish to use. The design professional must navigate these factors in the preparation of the design. Depending on the clients review and approval process, this phase of the project could take as long as eight to 10 weeks to complete.Figure 2 Image courtesy Timebie.comAverage Hours of Daylight /Month 181614This chart illustrates wind-chill temperatures based on ambient temperature and wind speed, along with the corresponding risk of frostbite. 12108Serving Southwestern Ontario Since 1972 64 Commercial Industrial 2 Maintenance SpecialistsFree Estimates / Inspection 0January February March April May June July August September October November December152 Thames Rd. W., Exeter, Ont. N0M 1S3 Tel: (519) 235-2802Fax: (519) 235-1532 Halifax Montreal VancouverEmail: speat@hay.net Average daylight hours between the summer and winter solstices in three cities across Canada.10ONTARIO ROOFING NEWSISSUE 3 2019 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'