What Are the Rules for Building a Boundary Wall?

Boundary walls are governed by a combination of the National Building Regulations and Building Standards Act, municipal requirements, zoning regulations and, in some cases, conditions contained in the property's title deed. The exact requirements can therefore differ from one municipality or property to another.

How high can a boundary wall be?

There is no single nationwide height that applies to every boundary wall.

The permitted height can depend on:

• The municipality

• The property's zoning

• Whether the wall faces a street or a neighbouring property

• Whether the wall is solid or visually permeable

• Whether security features are being added

• Whether the property is on a slope

• Local development-management requirements

• Conditions contained in the property's title deed

For example, the City of Cape Town's current Development Management Scheme provides that a street boundary wall may generally be up to 2.1 m high, while a common boundary wall may generally be up to 2.5 m high. The rules also contain specific provisions dealing with retaining walls and security devices.

This illustrates why homeowners should not simply use a "standard South African boundary wall height" when planning their project.

Street boundary walls versus neighbour boundaries

The rules can be different depending on where the wall is located.

Street boundary

A wall along the front of your property, next to the road or pavement, may have stricter requirements relating to:

• Maximum height

• Visibility

• Gates

• Pedestrian access

• Vehicle access

• Security features

• The appearance of the wall

Some zoning schemes also require a portion of a street-facing wall to remain visually permeable.

Common boundary

A wall separating your property from a neighbour's property can have different height requirements.

For example, Cape Town's Development Management Scheme allows a common boundary wall up to 2.5 m, measured from the lowest existing ground level on either side of the wall.

This measurement becomes particularly important on sloping properties.

What if the property is on a slope?

A sloping site can make boundary-wall measurements more complicated.

It is important to distinguish between a boundary wall and a retaining wall.

A retaining wall holds back soil, while a boundary wall primarily defines the property boundary. A structure can sometimes perform both functions, but additional requirements may apply.

Cape Town's rules, for example, specifically provide for retaining walls forming part of street and common boundary walls, with different maximum retaining-wall heights and requirements for balustrades.

This is one situation where simply measuring the wall from the finished ground level on one side can produce the wrong answer.

Can you add an electric fence or spikes to the wall?

Security features can also affect the permitted height.

Depending on the municipality, additional requirements can apply to:

• Electric fencing

• Spikes

• Barbed wire

• Razor wire

• Other security devices

For example, Cape Town's current rules state that certain security devices must not exceed 1 m above the top of the boundary wall, while also imposing minimum heights above ground level.

Electric fencing is also subject to its own safety and installation requirements, so it should not simply be added to a wall without checking the applicable regulations.

What about the neighbour?

If you are building directly on a common boundary, it is sensible to discuss the proposal with your neighbour before construction.

This is particularly important where:

• The existing boundary position is uncertain

• The wall will replace an existing shared wall

• The wall will be substantially higher than the existing wall

• The wall will be constructed partly on the neighbour's side

• The wall will retain soil

• The work could affect drainage

• Costs are expected to be shared

Remember that the position of the legal property boundary is not necessarily determined by where an old wall happens to stand.

If there is any uncertainty about the actual boundary, obtaining professional advice or having the boundary properly established before construction can prevent a costly dispute.

Drainage and stormwater

A boundary wall should not be designed without considering water.

If the wall prevents normal stormwater flow, water can accumulate against the wall or be diverted onto a neighbouring property or public area.

This can become particularly important on sloping sites or where a retaining wall is involved.

The wall should therefore be designed so that it does not create drainage problems, and any retaining structure should be appropriately designed for the loads and soil conditions involved.

Do boundary walls need foundations?

A masonry boundary wall should not simply be built directly on the ground.

The foundation needs to be appropriate for:

• The wall height

• Wall thickness

• Ground conditions

• Soil type

• Slope

• Wind exposure

• The type and spacing of piers

• Any additional loads

• Whether the wall is also retaining soil

Higher or unusual walls may require professional design.

For example, Mogale City states that an engineer's appointment and engineered boundary-wall design may be required for walls above certain heights.

This is another reason why copying the foundation details from another property is not necessarily appropriate.

Don't forget your title deed

Municipal approval does not necessarily mean there are no other restrictions.

Some properties have restrictive title-deed conditions or conditions attached to previous approvals.

These may regulate matters such as:

• Building lines

• Boundary walls

• Street boundaries

• Building height

• Access

• Development restrictions

Recent City of Cape Town land-use applications demonstrate that restrictive title-deed conditions can still be relevant to development proposals.

If you are planning a substantial boundary wall, it is worth checking the title deed as well as the municipal requirements.

How much does a boundary wall cost?

The cost can vary considerably depending on the design.

Factors include:

• Wall height

• Wall length

• Foundation requirements

• Brick or block type

• Face brick versus plastered and painted finish

• Number of piers

• Gates

• Demolition of an existing wall

• Site access

• Ground conditions

• Retaining requirements

• Electric fencing

• Labour

• Finishing and painting

For this reason, a simple price per metre should only be treated as a budget estimate, rather than a guaranteed construction cost.

A detailed building cost estimate can provide a better indication of the expected material and labour costs before construction begins.

Before you build your boundary wall

Before purchasing materials or starting construction, work through this checklist:

1. Confirm the property boundary Make sure you know where the legal boundary is.

2. Check the title deed Look for restrictive conditions that may affect the proposed wall.

3. Check your municipal requirements Confirm the permitted height, position, appearance and approval requirements.

4. Determine whether building-plan approval is required Do this before construction starts.

5. Check whether the wall is also a retaining wall Sloping sites require particular attention.

6. Plan drainage Make sure the wall will not cause water problems.

7. Discuss a common boundary with your neighbour Particularly if the wall is being built on or near the shared boundary.

8. Get the structure properly designed where necessary Higher walls, retaining walls and unusual structures may require professional input.

9. Get an accurate cost estimate Allow for foundations, brickwork, plastering, painting, gates, labour and any security additions.

There is no single boundary-wall rule that applies identically to every property in South Africa.

The National Building Regulations provide the broader regulatory framework, but your municipality's zoning and development-management rules can determine the specific requirements for your property.

Before building, check the applicable municipal rules, your property's zoning and title-deed conditions, and determine whether plans or other approvals are required.

Planning a boundary wall? Getting the design and quantities right before construction can help avoid unexpected costs and changes later. An accurate building cost estimate can help you budget for the wall, including materials and labour.