Property Boundaries & Beacons: What the SG Diagram Shows

If you have ever argued with a neighbour about where the fence should sit, or wondered exactly where your land ends, the answer is not in your title deed and it is not in the fence. It is in the Surveyor General (SG) diagram for your property. The SG diagram is the official survey of your erf or farm, and it is the document that legally fixes your boundaries and the beacons that mark them. This guide explains what survey beacons are, how the diagram defines them, and what to do when a beacon goes missing or a boundary is disputed.

What is a survey beacon?

A survey beacon, often called a peg, is a physical marker placed at each corner of a registered property by a professional land surveyor. It is the on-the-ground reference point that ties your land to a precise spot on the surface of the earth. Beacons can take several forms depending on when and where the survey was done:

• An iron peg or steel pin driven into the ground, sometimes capped with a concrete or plastic marker.
• A concrete beacon set flush with or just below ground level.
• A mark cut or drilled into rock, a kerb, or a permanent structure where a free-standing peg is not practical.

Each beacon corresponds to a labelled corner on the SG diagram. Together, the beacons describe the closed shape of your property — every turning point in the boundary has one.

How the SG diagram defines your boundaries

The SG diagram is a cadastral survey document. It does not deal with ownership, bonds or transfers — that is the title deed, a separate record kept at the Deeds Office. The SG diagram deals only with the geometry of the land, and it records:

• The position of every corner beacon, usually labelled A, B, C and so on.
• The length of each boundary line between beacons, in metres.
• The bearing (the surveyed direction) of each line, so the shape cannot be ambiguous.
• The total extent of the property — its size in square metres for an urban erf, or hectares for a rural farm or agricultural holding.
• Any servitudes that cross the land, such as a right of way or a municipal pipeline, drawn in their correct position.

Because the diagram pins each beacon to a coordinate and ties the lines together by length and bearing, it is the single legal authority on where your boundary runs. A fence, a hedge or a wall is only a structure someone built; it carries no legal weight on its own. If the fence and the diagram disagree, the diagram wins.

What to do about a missing or disputed beacon

Beacons disappear surprisingly often. They get dug out during building work, buried under paving, knocked out by vehicles, or simply lost to time and weather. A missing peg does not change your boundary — the boundary still exists exactly where the SG diagram says it does — but you may need it physically re-established to build a wall, settle an argument or sell with confidence.

Here is the important part: you cannot lawfully re-establish or move a beacon yourself, and neither can your neighbour. Only a registered professional land surveyor may re-establish a lost beacon. The surveyor uses the existing SG diagram, the surrounding survey data and precise measuring equipment to put the peg back in its exact original position. This is a re-establishment of a known point, not a fresh negotiation about where the line should be.

The practical steps when you have a missing or disputed beacon are usually:

• Obtain the SG diagram for the property so you and the surveyor know the surveyed corners, lengths and bearings.
• Appoint a professional land surveyor to locate and re-establish the beacon on the ground.
• Use the surveyor's findings to resolve any fence or wall placement, since the diagram and the re-pegged corners are the legal reference, not the existing fence.

How the diagram settles a fence-line dispute

Boundary disagreements almost always come down to a fence that was put up in the wrong place years ago, or two owners reading the ground differently. The SG diagram cuts through this. Because it records the exact length and bearing of each boundary and the position of each beacon, a surveyor can show, objectively, where the true line runs. If a fence sits over the line, the diagram is the evidence that proves it. This is why getting the diagram is the sensible first move in any boundary question — it replaces opinion with the surveyed facts.

You can check which SG diagrams exist for any property for free on SGCheck. Just search by address on the map, or by erf number, town and portion, and you will see the diagrams on record before you decide to download anything. It is the quickest way to get the survey facts in front of you when a boundary question comes up.

Frequently asked questions

Is the SG diagram the same as my title deed?

No. The SG diagram is the survey of the land — its boundaries, beacons, lengths, bearings, total extent and servitudes. The title deed is the ownership record showing who owns the property and any bonds or transfers. They are two different documents kept by two different offices. If you need ownership, bond or transfer information instead, that is what DeedsCheck is for.

Can I move or replace a survey beacon myself?

No. Only a registered professional land surveyor may re-establish or replace a beacon. They put it back in its exact surveyed position using the SG diagram and survey data, so the legal boundary is never changed by the process.

My fence does not match my boundary — which one is correct?

The SG diagram is correct. A fence is just a structure that someone built and it carries no legal authority over the boundary. Where the fence and the diagram disagree, the surveyed line on the diagram is the one that counts.

How do I find the SG diagram for my property?

Search your property for free on SGCheck by address on the map, or by erf number, town and portion. You will see which SG diagrams exist on record, then pay a single R230 fee to retrieve and download every diagram on the property as a PDF.