Enabling housing supply – Getting a minimum 2 hours sunlight in mid-winter

In 1915, the 42-story Equitable Building cast a seven-acre shadow over neighbouring buildings. This is what set the scene for modern town planning rules throughout America (The birth of zoning), and much of the world.  Property owners and home owners who have enjoyed access to the sun’s rays for a long time feel entitled to enjoy it in the indefinite future.   Town planning rules on height in relation to boundary (or recession planes) set the limits on developers’ rights to build and block sunlight, and a home owner’s rights to receive sunlight.  The Auckland Council submission to the government’s ‘Enabling Housing Supply’ bill proposed that parts of all dwellings should ‘Require 2 hours of sunlight at the winter solstice’ (p71).  This is to support mental and physical health; and enable the space to be used for recreation and other uses such as drying washing outside year-round (energy efficiency)’.

The key issue with recession planes in the ‘Enabling Housing Supply’ bill is that ‘buildings must not project beyond a 60 degree recession plane measured from a point 6 metres vertically above ground level along all boundaries’ (Link 1). This gives the developer too much right to build and block sunlight from a neighbouring home owner.  Compare this to a Japanese rule, which has the angle at 51 degrees measured from a point 5 metres vertically above ground level of a boundary (link 2).  Compare this to Hamilton’s 1990s Town plan rule ‘8.2.4 Height a) No part of any building shall protrude through a plane rising at an angle of 45 degrees commencing at an elevation of 3m at the boundary’. Preceding this, Hamilton’s 1960s District Scheme used an ‘Angle controlling height’ which included recognition that building heights have a relationship with the street width.

The Auckland submission suggests applying a current standard called ‘Alternative Height in Relation to Boundary’. This enables 3 storeys, but more effectively contains effects within the site – less shading, more privacy, and reduced dominance effects within the site and adjoining sites. Refer to the diagram and standard below. (p70)

Over the years, the Hamilton District Plan became more restrictive and rules describing ‘height in relation to boundary’ (rule 4.4.5) became more clever and harder to describe. What was once a single sentence is now spread over five pages, ending with an example similar to Auckland’s H5.6.6.2 Exception on how buildings are allowed to project 1m beyond the height control plane, thus technically allowing a localised 4m by 45 degree recession plane (Hamilton DP p18).

The right to sunlight has always been important; when we forget this, we end up with the situations found in The Condition of the Working Class in England (1845) by Friedrich Engels, and How the Other Half Lives: Studies among the Tenements of New York (1890) by Jacob Riis.

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Hamilton enabling housing supply and choice

Hamilton City Council’s examples in response to the Government’s ‘Enabling housing supply’ consultation are likely to supply 437 to 625 car-free, 50m2 dwellings over this decade, which is 3.5% to 5% of the total 12,500 dwellings needed to meet Hamilton’s housing market in this decade, and these 50m2 dwellings will need about 20,000m2 (2 hectare), compared to (400m2 x437=174,800m2 (17.5h)) to (400m2 x625=250,000m2 (25h)) under existing rules in general residential zones.

Today Hamilton’s population is approximately 180,000 people (p92 LTP), living in approximately 53,000 households (p66 LTP) which averages 3.4 people per dwelling. In about 10 years’ time, Hamilton’s population is projected to be about 200,000 people (p92 LTP) living in an assumed additional 12,500 houses (p17 Infrastructure LTP). This total of 65,500 households averages 3 people per dwelling. It has been stated that ‘around half (49%) of Hamilton household are 1-2 person households’ (p45 FutureProof). So half of the new 12,500 dwellings, which amounts to 6,250 dwellings  households, could be 50m2 dwellings suitable for 1-2 person households. We also know that 7%-10% of households are car free (link), which suggests there could be a market for 437 to 625 dwellings with no need for car parking space. Hamilton’s submission to the government enquiry on ‘Enabling housing supply’ showed that 437 to 625 car parking-free 50m2 dwellings could be accommodated on ten 2,000m2 parcels of land or thirty four 600m2 sections or fifty two 400m2 sections. (Hamilton submission from page 49)

Where is there demand for 50m2 dwellings with no car-parking? In the city centre, and in close to a dozen other neighbourhoods with over 10% of households that are car-free in Hamilton. Where is there almost no demand for car-free living? Flagstaff South. If a developer built 50m2 dwellings with no car-parking in  Hamilton’s most expensive neighbourhood, which also has the lowest level of walking/biking/busing to work, the outcome would be more affordable homes and the next census would show an increase in the number of people walking/biking/busing to work.

Amersfoort Space boxes

Final note: The key issue is the right to sunlight for existing and future homes. The Auckland submission requires a ‘minimum 2 hours sunlight at mid-winter solstice’ page 70.

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