Building in a landslip area in Hobart

Much of Greater Hobart is built on slopes, and some of those slopes have moved before. Tasmania manages the risk with a statewide map and two sets of rules: the Landslip Hazard Code in the planning scheme, and the Director's Determination for building work in landslip hazard areas.

Landslip areas in Hobart: quick facts

Where to check

LISTmap or Risk Ready, landslip hazard layers

Regulated bands

Low, medium, medium-active and high

Approvals

Low-risk work becomes notifiable; high-band house work becomes permit work

Who reports

A geotechnical practitioner, such as a licensed Engineer – Civil

Method

AGS 2007 risk assessment, AS 1726-2017 site investigation

Our fee

Fixed quote per job, within 1–2 business hours

How do you check whether your Hobart block is in a landslip area?

You check the band on the state's landslip mapping, published on LISTmap and the Tasmanian Government's Risk Ready tool. Search the address, turn on the landslip hazard layers and look at the whole lot, not only the house: a block can be partly in a band, and the rules apply to work in that part. Your council's planning scheme overlay shows the same areas, and older declared Landslip A and B areas sit in the high and medium bands.

Under the Building Regulations 2016 (regulation 59), a landslip hazard area is land on the planning scheme's landslip overlay within one of the bands. Outside a band the landslip rules don't apply, although a steep or wet site still needs proper site classification and footing design.

What do the landslip hazard bands mean?

The bands describe how much control the state applies to new building on that land, from no specific controls to strict limits. The Landslide Planning Map sorts all land into five bands. The lowest, Acceptable, carries no landslip controls. The other four form the regulated overlay.

Summarised from the January 2026 landslip fact sheet and the Director's Determination. The medium-active and high bands mark land where a landslip has happened in roughly the last 200 years.

What changes for approvals in a landslip band?

A landslip band lifts work one category: work that would be low risk elsewhere becomes notifiable, so it needs a building surveyor and a Certificate of Likely Compliance. Class 1 work in the high band becomes permit work. Our building approvals guide explains the four categories.

On the planning side, most building work is handled through the building rules instead of the planning code. The Landslip Hazard Code still applies to subdivision, to critical, hazardous and vulnerable uses, to development in the medium-active and high bands, and to significant works in the low and medium bands.

Retaining walls are a common trap. A wall that would be low risk on flat land isn't low risk in a landslip band, so it needs a designed retaining wall and a building surveyor. Our retaining wall rules guide has the height limits.

What does a landslip hazard report contain?

A landslip hazard report shows that the work won't cause or contribute to a landslip on the site or next door, and that it can reach and keep a tolerable level of risk for its life. It is prepared by a geotechnical practitioner: a licensed Engineer – Civil, a geotechnical engineer or an engineering geologist.

The method is the Australian Geomechanics Society's Landslide Risk Management guidelines (AGS 2007), applied through Mineral Resources Tasmania's 2016 guidance on geotechnical reporting. The ground investigation follows AS 1726-2017, the Australian Standard for geotechnical site investigations. A typical report works through these steps:

1. Step 1

   Desktop review and site mapping

   The band, MRT's landslide inventory, geology and past reports, then slope angles, cracks, seepage and signs of past movement on site.

2. Step 2

   Site investigation

   Boreholes or test pits, soil and rock logs and groundwater, to AS 1726-2017. Fieldwork may be done with our geotechnical partner, [geotechnical partner].

3. Step 3

   Risk assessment

   The likely landslide types, how often they could happen and what they would affect, for property and for life, to AGS 2007.

4. Step 4

   Recommendations and certificate

   Footing type and depth, limits on cut and fill, retaining, drainage and staging, usually certified on a Form 55.

5. Step 5

   Design and approval

   Footings and walls designed to the report, with a Form 35, then the building surveyor's Certificate of Likely Compliance.

AGS 2007 sets a tolerable risk to life of about 1 in 100,000 per year (10⁻⁵) for new development, stricter than the 1 in 10,000 (10⁻⁴) for existing development. In practice that means footings into firm material, controlled drainage and limits on how much the slope is cut or loaded.

Where have landslides damaged houses in Greater Hobart?

Rosetta and Taroona are the two documented landslide areas in Greater Hobart. Mineral Resources Tasmania records that the Rosetta landslide in Glenorchy has damaged or led to the demolition of 23 houses since 1992. MRT thinks an older, disguised landslide existed there and was reactivated by subdivision and development. The Taroona landslide in Kingborough affected 10 houses and a high school. Statewide, more than 170 buildings have been damaged or destroyed by landslides since the early 1950s.

Taroona also shows why diagnosis matters. A 1977 Department of Mines study of house damage in Taroona found that expansive clay, moisture change and inadequate footings caused most of it, with landslip a less common cause. Cracks on a sloping block are not always a landslip. Our guide to Hobart's reactive clay soils covers the other common cause. Local detail is on our Taroona and Glenorchy pages.

Is the Tasmanian landslip map changing?

Yes, but the update isn't in force as the statutory overlay yet. Mineral Resources Tasmania reviewed the 2013 Landslide Planning Map between February 2024 and December 2025 and published its final report on 18 December 2025. The update keeps the same five bands (acceptable, low, medium, medium-active and high), uses newer data such as a LiDAR-based 10 m elevation model, and adds a recent or active landslides layer.

Statewide, the regulated area grew by 5.6%, mostly in northern council areas. Hobart and Glenorchy saw a reduction in total hazard area, after refinements to rockfall modelling on the lower slopes of kunanyi / Mount Wellington. When we checked in November 2026, MRT said the new mapping will eventually replace the existing statutory mapping and that it is working with the State Planning Office on the process. We could not confirm that it has been adopted, so check both the current overlay and the 2025 map for your block.

Can you still build a pool, retaining wall or extension in a landslip band?

Usually yes in the low and medium bands, if the design follows the site classification and any landslip report. What matters is how much you cut, fill, load and wet the slope:

• Pools over 45,000 litres are significant works on their own. See a pool on a sloping block.
• Retaining walls need a designed wall with drainage.
• Extensions and granny flats need engineer-designed footings and often a report.
• Stormwater discharged onto a slope can trigger movement. See stormwater and drainage.

Bushfire-prone land often overlaps steep, vegetated slopes. We don't prepare bushfire assessments: a bushfire hazard practitioner prepares that.

When should you call a structural engineer about landslip?

• Your block is in a band and you're planning a house, extension, granny flat, pool or wall
• Your building surveyor or council has asked for a landslip hazard report or engineer-designed footings
• You can see ground movement: curved cracks in the lawn, leaning fences or poles, new cracks in walls or paths
• Water is appearing where it didn't before: seepage, soggy ground or a broken pipe on a slope
• You're buying on a slope in a mapped band and want to know what you could build