Buying Filled Land: How to Check Its Compaction and History

In South Kalimantan, a lot of the land on offer has already been filled. From the roadside it looks flat and dry. What decides how your house will fare is what lies under the surface.

This guide is for anyone buying a plot or a house on filled land (tanah urukan). It covers the risks, the questions to ask the seller, the checks to make on site, and how to estimate the cost of fill yourself.

Why so much land in South Kalimantan is filled

Banjarmasin is low-lying and tidal, and much of South Kalimantan’s lowland is swamp (rawa) and peat (gambut). Land that sits below the road floods easily. So owners raise their land to road level or above the flood line before they build.

The usual fill materials are fill soil (tanah urug) and fill sand (pasir urug). The trouble is that not all fill is placed the same way. Some is laid in layers and compacted, and some is simply dumped. What swampland is like is covered in homes on Banjarmasin’s swampland.

The risks of filled land

• Settling for years. Fill adds weight on top of the soft layer, and that layer keeps compressing.
• Uneven settlement. Different fill depths or uneven compaction make one part sink more than another. The result is cracked walls and sloping floors, as explained in reading wall cracks and ground settlement.
• Organic material left underneath. If grass, roots, mud or peat were not removed before filling, that layer rots and compresses under the fill.
• Poor fill material. Rubbish, wood and demolition waste rot or shift and leave voids.
• Water pushed onto the neighbours. Raised land sheds water onto lower land, and that can start disputes.
• Land status unchanged. A rice field or swamp that has been filled still follows the use set in the spatial plan. See buying rice fields to build on.

Questions for the seller

• When was the land filled? In one go or in stages?
• How deep is the fill compared with the original ground?
• What material was used, and where did it come from?
• How was it compacted? Layer by layer with a compactor, or dumped and left to settle?
• Were the grass, roots and mud removed first?
• Who did the work, and are there receipts or photos of the process?
• For a plot in a housing estate, was the whole estate filled at once or plot by plot?
• Has there been any standing water or sinking since the land was filled?

A vague answer means the history is unknown. Treat it that way, and build the risk into your offer and your foundation plans.

What you can check yourself on site

• Timing. Visit after heavy rain to see where water collects and which way it flows.
• The surface. Look for cracks in the ground, hollows holding water after rain, and patches that have sunk.
• Firmness. Walk the whole plot. Note any area that feels springy or soft. With the owner’s permission, push a steel rod into the ground at several points and compare how easily it goes in.
• Material. Look at the surface and the edges of the fill. Rubbish, bits of wood, broken bricks or black, smelly soil all point to poor fill.
• Levels. Compare with the road and the neighbouring plots, and watch where water runs.
• Nearby buildings. Fences or houses next door on similar fill show what may happen to yours. Are they cracked or leaning?
• Old satellite images. Some map apps keep imagery from earlier years, so you can see when the plot was still swamp.
• The neighbours’ memories. Ask when the land was filled and what it was like before. An old ditch or pond that was filled in is usually a weak spot.

Other checks for empty land, from boundary markers to utilities, are in our guide to inspecting vacant land.

Soil tests and foundation costs

Looking only tells you about the surface. To know what lies beneath, there are two common tests:

• Uji sondir (cone penetration test). A cone-tipped rod is pushed into the ground and the soil’s resistance is recorded at each depth. The results show how deep the soft layers go and where firmer ground starts.
• Boring. The ground is drilled to take samples from several depths. That shows which layers are there, such as fill, peat or soft clay, and how thick each one is. The samples can be tested in a soil mechanics laboratory.

These tests are done by soil investigation firms. Ask a structural engineer to decide how many points need testing.

The results feed straight into cost. The deeper the soft layer, the longer or more numerous the piles you need, whether galam timber piles (cerucuk) or concrete piles. A floor on deep fill may also need to be carried by the structure. Include this foundation estimate when you compare the prices of different plots.

Estimating the fill yourself

If the land is not yet as high as you need, estimate the volume yourself before you make an offer.

The formula: compacted volume = plot area x fill depth. Add an allowance for shrinkage during compaction and for fill that sinks into soft ground. Divide by the capacity of one truck to get the number of loads.

Worked example (illustrative numbers only):

• Plot of 10 m x 20 m = 200 m²
• Raised by 1 m, giving a compacted volume of 200 m³
• An allowance of 30 percent, making 260 m³ (the real allowance is set by the contractor for the material and the ground)
• If one truck carries 6 m³ (ask the supplier for its truck capacity), that is about 44 loads

The total cost is the number of loads times the price per load, plus spreading, compacting in layers and building drains. Ask a contractor to rework the numbers before you decide. Remember too that freshly spread fill will still settle, so don’t build straight away on fill that hasn’t been properly compacted.

Drainage and your duty to the neighbours

Raising land changes where water goes. Water that used to sit on your plot will look for somewhere else, usually the lower land next door.

• Build a drain along your boundary that carries water to a ditch or public drain, not into a neighbour’s yard.
• Don’t block existing ditches. If you have to cross one, keep it flowing with a culvert or a large enough pipe.
• Talk to the neighbours and the head of the RT (the neighbourhood unit) before you start filling.
• Maintain the drains after you build. A blocked drain brings the standing water back.
• Ask the kelurahan or the Dinas PUPR (the public works and spatial planning office) about drainage lines and local rules. In some areas, filling swampland touches on local zoning and drainage rules.

If you are buying land that has already been filled, ask whether the neighbours ever complained about standing water after the filling.

What to do next

Ask the seller about the history of the fill, inspect the land yourself, and get a sondir done before the price is final if you plan to build soon. Put the cost of extra fill, foundations and drains into your numbers alongside the price per square metre.

The plots Vorneo is marketing are on our land plots for sale page.