What can I build on my property? How to work out development potential

"What can I build on my property?" sounds like a question with a one-line answer. In practice it is answered by working through a sequence of limits, each of which can reduce what the one before allowed. The good news is that the sequence is always the same, and the first pass can be done in an afternoon.

This is the method small developers and planners use to assess development potential.

Step 1: Start with the use

Find the zoning. It tells you which uses are permitted, which need consent and which are excluded.

A Residential 1 erf gives you a dwelling house, possibly with a second dwelling.
A Residential 2 or 3 erf gives you multiple dwelling units.
A Business 1 erf gives you commercial uses and usually residential as well.

If what you want to build is not a permitted use, stop here: you are looking at a consent use or a rezoning, and the rest of the analysis is about what you might get, not what you have.

Do a zoning check to start.

Step 2: Apply the density

For residential development, density caps the number of dwelling units. It is expressed either as units per hectare or as one dwelling per erf of a minimum size.

Units by density = erf area in hectares × permitted units per hectare

An erf of 1,500 m² is 0.15 ha. At an illustrative 60 units per hectare, density allows 9 units.

Step 3: Apply floor area, coverage and height

Next, how much building the erf may carry.

Floor area ratio × erf area gives total permitted floor area.
Coverage × erf area gives the maximum footprint.
Height gives the number of storeys.

Divide usable floor area by a realistic unit size. Remember that not all floor area is sellable: passages, stairs, lifts and lobbies take a share.

If density allowed 9 units but floor area only fits 7 of the size your market wants, the answer is 7. See floor area ratio, coverage and height restrictions.

Step 4: Take off the land you cannot use

Now reduce the erf to its buildable area.

Building lines along the street and other boundaries. See building lines.
Servitudes for sewers, stormwater, electricity or access.
Floodlines, where a watercourse affects the erf. See floodline checks.
Awkward geometry — panhandles, sharp corners, steep slopes.

On a small erf this step often removes a third or more of the land.

Step 5: Fit the parking

Parking is where many paper schemes fail. Each use carries a parking requirement, and each bay with its share of aisle and manoeuvring space takes a surprisingly large area.

If parking does not fit at ground level, the options are fewer units, smaller units, or structured parking — which changes the cost of the project completely.

Step 6: Check the title deed

The scheme may allow it. The title deed may not.

Restrictive conditions in older townships commonly limit an erf to one dwelling, prohibit business use, or set building lines. They must be removed or amended before the development can proceed. See title conditions.

Step 7: Check the ground

Dolomite affects what may be built and how. See dolomite risk.
Soil conditions affect foundation cost.
Slope affects earthworks and access.

Step 8: Check services

An erf serviced for one house is not automatically serviced for ten units. Water, sewer, stormwater and electricity capacity may need upgrading, and the municipality may levy contributions for external engineering services. This is frequently the largest cost a first-time developer did not expect.

The answer is the lowest number

After eight steps you have several different answers to "how many units can I build?" — one from density, one from floor area, one from the buildable footprint, one from parking. The lowest one is your yield.

Write the result down as a range, not a single figure, and note which control is binding. If floor area is the limit, a rezoning for more FAR might unlock more. If parking is the limit, more FAR would not help at all.

Rights you have versus rights you might get

Keep two columns.

Existing rights — what the current zoning allows. This is what you can build with only a site development plan and building plans.

Potential rights — what an application might deliver. This depends on the City's planning policy for the location. See densification in Johannesburg.

Land is usually priced somewhere between the two, depending on how confident the market is that new rights will be granted. Paying a potential-rights price for an existing-rights erf is the classic mistake.

Doing the first pass quickly

For a Johannesburg erf, checkproperty.co.za gathers the inputs for this assessment in one report:

erf size and boundary;
zoning, with density, height and parking zones;
building lines and the planning framework guideline for the area;
title deed reference, servitudes and the survey diagram;
floodline, dolomite and soil constraints;
where the rules for the zone have been verified, permitted uses, coverage and an assessment of second-dwelling and subdivision potential.

That is the Development potential report; the Basic report covers the property and market information. Details are on the pricing page.

The first pass tells you whether to keep going. If it does, the next step is a town planner and, for anything substantial, a proper feasibility study.

Frequently asked questions

Can I build more than the zoning allows? Only by applying for more rights. Building first and applying afterwards is a costly gamble.

Does a bigger erf always mean more units? Not if parking, shape or a servitude is the binding limit.

Do I need a town planner? For screening, no. Before you buy on the strength of development rights, yes.

The bottom line

What you can build is the least of what the use, density, floor area, buildable footprint, parking, title deed, ground and services each allow. Work through them in order and the answer comes out reliably.

Check a property's development potential.

This is general information, not town-planning advice. Figures are illustrative. Development rights for a specific erf must be confirmed with the municipality or a registered town planner.