Function Junction- Completed 2011

Winter 2011, I was called to investigate a possible mold infestation.  The 2nd floor apartment had black drips on the exterior walls and a bad smell.  The tenants complained of headaches and watery eyes.

Upon investigation I found the roof cavity was completely covered with thick black mold.  The warm moist air rising from the 1st floor bakery was causing additional condensation.  The roof cavity had close to no cross ventilation and the air was condensing in the cavity.  Over the years this caused extensive damage.

The remediation process included rebuilding the roof from the top.   The 24”  TJI’s were replaced, cross ventilation was added in the roof chamber, the insulation and roof were rebuilt as original.  The roof was vented with the aid of electric fans.


  • No ventilation system in bakery to remove moist hot air
  • I cut holes in gyroc ceiling to see inside roof cavity 
  • Roof structure was 24 in. trusses (TJI’s) t on 2 ft centres with 12 in. of insulation.
  • Removing insulation showed entire wood structure infested with black mold, the insulation was blocking the outside vents and the roof had been leaking for years and was in need of replacement


  • The suite was deemed contaminated space and tenant advised to move
  • Environmental hygiene consultant hired to conduct evaluation. My scope of work and corresponding pricing was based on their recommendations


  • Poly off affected areas and connect a fan system to outside. This creates a negative air chamber to prevent cross contamination of mold spores to surrounding areas


  • all drywall ceilings and insulation carefully removed and transferred by chute to waste disposal truck
  • all interior walls removed since they had been contaminated with black liquid
  • revealed many trusses were rotten and the roof sheathing was OSB particle board that cannot be remediated as the mold grows into the structure


  • Recommendation from PEC was to remove all black mold from the trusses (TJI’s) and roof sheathing but due to the findings the complete roof needed replacement including new plywood sheathing and 26 trusses needed replacement
  • As the OSB was removed above the suite my crew replaced the trusses from the top
  • Remaining trusses were sanded to remove all signs of black mold
  • As the plywood was being replaced across the building I inspected the joists and confirmed that the mold had not spread beyond the suite
  • Negative air system was removed once remediation stage was complete
  • Blower was left on for 2-3 days to provide “air scrubbing”. The air is circulated through HEPA filter several times per hour which removes the remaining mold spores from the air.
  • Every surface then vacuumed with HEPA vacuum and washed with soap and water. This process repeated 3 times to ensure success.


  • When remediation and cleaning was complete, the environmental consultant was called back in to conduct an air quality test that verifies the mold spore count is acceptable.
  • This certified the work was successful and conducted according to the recommendations in the original report


The hard part is now done and the suite is ready to rebuild to the standard desired by owner . This unit is reframed, rewired, drywalled and painted. New doors and trim added, ceramic tile and hardwood flooring repaired. New carpet installed in the bedrooms. Unit handed over to owner. Project deemed a success and the suite is rented immediately.



"I was in the process of buying a commercial building and during the course of my due diligence we uncovered a potential mold problem in the building.  Steve was referred to me as an expert in the subject matter which proved to be the case.  He identified the problem and came up with a cost effective solution to solve the problem. Steve was able to work within a budget, set time frame, coordinate the trades and liaison with the tenants in a professional and respectful manner.  I would highly recommend Steve for any building envelope issues internal or external and contracting  jobs you may have. If you need a reference feel free to call me 604 290 7712." 
Hendrik Zessel Senior Managing Director Cushman & Wakefield Ltd.