A Sun and Shadow Study models the shadows a proposed building will cast on streets, parks, open spaces, and neighbouring properties across the year, and tests them against municipal shadow protection policies. It is required for most mid-rise and tall-building applications. It is prepared by an architect or urban designer using 3D modelling, and where it shows unacceptable shadowing on protected spaces it can force a reduction in height or a change in massing.
A Sun and Shadow Study is where height meets its limit. Many municipalities protect specific parks, sidewalks, and open spaces from new shadow at defined times of year, and the study is what proves whether a tower respects those protections. When it does not, the fix is usually fewer storeys, which is why the study belongs in early massing, not final submission.
A Sun and Shadow Study, sometimes called a shadow impact study, uses a three-dimensional model of the proposed building and its context to render the shadows it casts at key dates and times, typically the spring and fall equinoxes and the summer solstice, across the day. It measures the incremental new shadow on public and private spaces.
The study is judged against municipal shadow protection policies, which set out which spaces, parks, playgrounds, key sidewalks, are protected and for how much of the day they must retain sunlight. It usually accompanies the Urban Design Brief and, on tall buildings, feeds into the design review panel’s assessment of massing.
A Sun and Shadow Study is required for buildings tall enough to cast meaningful shadow, including:
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Check my site →A Sun and Shadow Study is prepared by an architect or urban designer using 3D modelling software, often the same firm producing the Urban Design Brief. Municipal urban design staff and any design review panel assess it against the applicable shadow policies.
A complete Sun and Shadow Study typically contains:
| Factor | Typical range | What drives it |
|---|---|---|
| Consultant fee | $3,000 to $15,000+ | Building height, context modelling, and number of test dates |
| Preparation time | 2 to 5 weeks | Coordinated with the design brief and any panel review |
| Municipal review | Weeks, plus design review where applicable | Circulation to commenting agencies and revision cycles |
The study is inexpensive relative to what it can cost you: an adverse shadow finding on a protected park can require removing storeys, which changes the entire pro forma. Run a preliminary shadow test at the massing stage before committing to a height.
Shadow protection is strongest in cities with active tall-building programs. Toronto protects specific parks and sidewalks under its shadow policies and applies them through the design review process. Mississauga, Vaughan, and Markham apply shadow criteria in their growth areas and around transit. Municipalities without a tall-building context may require only a basic study or none, so the same tower can face very different shadow scrutiny across the GTA.
A sun and shadow study models the shadows a proposed building casts on streets, parks, open spaces, and neighbouring properties at key dates and times across the year, and tests them against municipal shadow protection policies. It uses 3D modelling and is prepared by an architect or urban designer. An adverse finding can require reducing height or changing massing.
A shadow study is required for most mid-rise and tall-building applications, for development next to parks, open spaces, or protected sidewalks, and for intensification in areas with shadow protection policies. Proposals seeking height beyond the as-of-right form almost always require one.
A sun and shadow study typically costs between $3,000 and $15,000 or more, driven by the building height, the extent of context modelling, and the number of test dates required. It is inexpensive relative to the redesign an adverse finding can force.
A shadow study typically models the spring and fall equinoxes and the summer solstice, showing shadows through the day at set intervals. Municipal shadow policies define which dates and times apply and how much sunlight protected spaces such as parks and key sidewalks must retain.
Yes. If a sun and shadow study shows a proposal casts unacceptable new shadow on a protected park, open space, or sidewalk, the municipality can require removing storeys or stepping back the upper floors to comply with its shadow protection policy. Testing shadow early in massing avoids a late height reduction.
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