1970s Apartment Roof Replacement in St. Catharines

PROJECT OVERVIEW

How We Built a Better Roof for a 1970s Apartment

This project involved a small apartment building constructed in the 1970s. The original four-ply built-up roof had reached the end of its service life, so we replaced it with a two-ply modified bitumen system (which is stronger, cleaner, and easier to maintain).

To improve drainage, we added external scuppers. These give the roof more exit points for water, reducing the risk of ponding and related damage.

We also tackled insulation as the old roof offered very little thermal protection. We installed tapered insulation starting at about 5 inches in the center and sloping down to 1–1.5 inches at the scuppers. This boosts the building’s R-value by three to four times, dramatically improving energy efficiency and indoor comfort.

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What is R-Value?

R-value measures how well a material resists heat flow. The higher the R-value, the better it insulates. In roofing, that means:

• Lower energy bills – Less heat escapes in winter, and less heat enters in summer.

• Longer roof life – Reduces thermal stress on the roof system, which can extend its lifespan.

• Meets code & efficiency goals – Many regions require minimum R-values for roofs to meet building codes and energy standards.

• Better comfort – Helps maintain more stable indoor temperatures.

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Project Challenges

• Aging roof at end of life – The original four-ply built-up roof from the 1970s was worn out and no longer providing reliable protection.

• Poor drainage design – Limited water exit points increased the risk of ponding and long-term damage.

• Low thermal performance – The existing insulation offered minimal R-value, leading to heat loss in winter and heat gain in summer.

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Project Location:

• St. Catharines, Ontario