Final Report Team Hadati Road: Integrated Structural and Solar Performance Analysis of a Monopitch-to-Flat Roof for a 24-Unit Townhouse Development (located at 140 Hadati Road, Guelph)

Abstract

This report presented the final capstone analysis for the project titled Integrated Structural and Solar Performance Analysis of a Monopitch-to-Flat Roof for a 24-Unit Townhouse Development at 140 Hadati Road, Guelph, Ontario. The work investigated how roof geometry affected structural demand, photovoltaic potential, zoning feasibility, and overall project value for a proposed low-rise multi-unit residential development. The central problem was that a conventional roof choice could not be evaluated on appearance alone. On this project, the roof had to satisfy several competing requirements at the same time. It had to remain feasible within the site’s height constraints, perform safely under local snow and wind conditions, support rooftop solar generation, and create value for the owner, Dotty Lake Retreats, without introducing unnecessary detailing risk. The project had compared five different roof forms: a full monopitch roof, a multi-gable roof, a butterfly roof, a flat roof, and a monopitch roof that transitions to flat at the zoning height limit.

The project used a comparative engineering design approach supported by preliminary structural calculations, load-path reasoning, photovoltaic sizing, energy-yield estimation, bracing analysis, and an interior-volume ROI assessment. The common basis for comparison was drawn from the project footprint and climate assumptions. This involved a building length of approximately 38.521 m, a span direction of approximately 14.200 m, a roof dead load of 0.65 kPa including PV, Guelph climatic values of ground snow Ss = 1.9 kPa, associated rain Sr = 0.4 kPa, and hourly wind pressure q1/50 = 0.36 kPa. These assumptions were used to generate comparison metrics across different roof options, including baseline snow load, drift-sensitive hotspot load, beam-equivalent factored moment, PV system size, annual energy yield, and bracing demand.

The study found that the full monopitch roof delivered the strongest solar and average structural performance, but it was the least compatible with the zoning height constraints. The flat roof was the simplest option from a zoning and massing perspective, but carried the highest baseline snow load and lower solar upside. The multi-gable and butterfly roofs were both disadvantaged by fragmented drainage, more complicated detailing, reduced continuous PV coverage, and more severe localized drift conditions. The monopitch-to-flat roof emerged as the best overall concept because it retained most of the solar and spatial advantages of a sloped roof while respecting the site envelope. This option produced approximately 90.1 kWdc and 99–113 MWh/year, while the preliminary package’s conservative mixed-roof estimate produced approximately 80.4 kWdc and 92,500 kWh/year depending on coverage assumptions. Overall, the recommended direction to my clients and stakeholders was to proceed with the monopitch-to-flat concept as the preferred design, while using a flat roof as the fallback option if simplified permitting, massing, or cost certainty became the dominant consideration.