Have you upgraded your roof to avoid winter leaks? Has your commercial roof been inspected in the last year? If yes, and you have addressed any roof condensation issues, you’ve made smart decisions. If not, you could be in for a rude awakening in the form of costly leaks, damp insulation, mould and mildew, interior damage and ice dams. The longer you wait, the more serious the problems become.
Here are some valuable tips to protect your commercial roof from condensation.
Condensation challenges with flat roofs and commercial buildings
Condensation is a sign that you need to make changes affecting your roof this winter. When condensation is not identified and attended to, you run the risk of leaks and property damage that will only become worse over time. Common upgrades to head off condensation include ventilation, insulation, humidity control and sealant.
With wintertime humidity and condensation, flat roofs and commercial buildings face a variety of challenges. Flat roofs are prone to pooling water, thermal bridging and limited ventilation. Commercial buildings are often large, complex spaces that may have improperly balanced HVAC systems. In addition, human activity, machinery and operational processes can all generate moisture.
When signs of condensation are visible or revealed in an inspection, it’s important to upgrade with the proper roof accessories to minimize condensation.
Here’s a rundown of accessories and condensation-fighting methods your roofer may recommend.
Ensure roof accessories are insulated to minimize condensation
Winter in Toronto requires insulated roof exhaust vents. A critical component of the ventilation system is plumbing vent stacks. While plumbers generally do not use stacks with an insulation lining, this type of accessory can greatly reduce the risk of problems over time. The same is true of washroom exhaust vents. Other areas to be insulated include parapet walls and rainwater leaders (using insulation wrap).
When considering vents, find the right balance of durability, compatibility with roofing materials, energy efficiency, ease of installation and maintenance, and potential cost savings versus durability and longevity.
Winter condensation from abandoned roof accessories
Abandoned tall cones, vents, or curbs may be spotted during a visual or professional inspection. Tall cones cover pipes or conduits that penetrate the roof, vents facilitate air movement, and curbs support and elevate equipment or features.
Letting unused or damaged accessories remain on the roof invites water intrusion and condensation where thin metal surfaces let hot inside air meet cold outside air. Steps should be taken to ensure there is no point of contact between warm and cold areas, such as flashing, insulation and proper drainage systems.
Ineffective or missing seals
Missing or ineffective seals in seams between roofing and building envelope materials and around penetrations can cause condensation when warm, moist inside air meets cold outside air.
Other areas of improper or missing seals can include:
- Single-pane windows or thermal units (where the seals have failed)
- Skylights with damaged or missing condensate drain pans or older single-dome skylights
- Joints and gaskets on glass curtain walls
A professional inspection can identify ineffective or missing seals that let moisture penetrate the roof–causing leaks, damaged insulation or other problems. If seals are left unrepaired, the resulting problems are likely to spread to other areas of the building. This can add to the cost of repairs.
Preventing roofing condensation issues with moisture absorbers
Moisture absorbers are designed to reduce humidity levels in enclosed spaces to help mitigate roof condensation issues, prevent mold and mildew, and protect insulation and other roofing materials.
Some moisture absorbing options commonly used for flat roof buildings are:
- Dessicant-based moisture absorbers, such as silica gel, calcium chloride, or bentonite clay, can be used in small spaces, such as storage areas.
- Absorbent panels or pads can be placed near vulnerable areas like HVAC units, skylights, or roof penetrations.
- Vapour barriers can be installed under insulation layers or roofing membranes to prevent moisture from reaching insulation and structural components.
- Activated charcoal filters can absorb moisture and odors from small spaces, such as mechanical rooms and equipment enclosures.
3 examples of roof condensation issues
Example 1 – Cheque Printing Facility (Markham)
We worked on a single-tenant building whose business involved printing cheques. The tenant sprays a fine water mist inside to keep humidity levels high, preventing the paper from sticking together. We diagnosed that the mist elevated the humidity, acting as a trigger for winter condensation issues. With the problem identified, the landlord was able to find an appropriate solution with the mechanical contractors.
Example 2 – Commercial Printing Operations (Vaughan):
This single-tenant building has a printing operation. The first winter after the new roof was installed, condensation from inside the HVAC units caused blocks of ice to land on the roof. Condensation also caused the inside of the office windows and the front entry door area to become completely drenched. After a consultation, the company purchased a newer machine to spray a cold ionized mist. This properly controlled the humidity levels and eliminating the condensation issues.
Example 3 Aquarium Shop (Etobicoke):
This multiple unit building was purchased several years ago and converted to industrial/commercial condominium units. There were three active leaks in one of the units, with morning temperatures of approximately minus 25 degrees Celsius. The three leaks were all directly below single-wall, galvanized metal “C” vents that were installed to remove excess humidity, rather than more typical double wall “B” vents. These vents, installed by an HVAC contractor, allowed the cold outside air and warm, moist inside air to meet, triggering the three condensation-related leaks.
The importance of inspection and regular maintenance
There are two key lessons to be learned from this article. First, ensure your building is professionally inspected twice a year to identify potential or active condensation and leaks. Second, keep your vents, drains, seals and other accessories well maintained to avoid the risk of roof condensation issues.
Related information: How to Prepare Your Commercial Roof for Fall and Winter
Inspect and Upgrade Your Roof with a High-Quality Contractor
In your ongoing fight against damage caused by humidity and condensation, always hire a reputable, experienced roofing contractor who understands the proper methods and accessories to address condensation. Effective leak prevention also requires hiring a roofer with the highest level of craftsmanship.
While these steps will substantially reduce the risk of property damage, unexpected situations can arise—especially with winter’s cold and storms. Get the greatest protection by hiring Toronto’s premier commercial roofer, with 24/7 emergency service. Contact us today and get The Elite Advantage.
