Sub-Divided Block Issues

Want to build a new house in an established suburb?

One way is to look for a subdivided block, or even buy a house on a big block and sub-divide yourself.

I see quite a lot of large suburban blocks sub-divided with one, or more, house blocksadded.

In a number of cases the original house the original house is demolished and 3 houses are built on the block.

If you want to build the available block will normally at the rear known as a Battle Axe Block

So what do you need to think about when considering a subdivided blocks?

Here are some issues to consider:

Vehicle Access

Any shared vehicle access can be a cause of contention so a separate driveway is much the preferred option.

If you have the rear block and put a gate near the front this can provide extra play space for young children. That can be very useful as the backyard area will be fairly limited.

Adequate Off-Street Parking

With two properties sharing one frontage and the loss of parking if there are two crossovers On-Street parking will be at a premium.

I would recommend having space for at least two vehicles off the street (this can include the garage)


When you are squeezing a house on a small block windows are going to be closer to your neighbours on all sides, so overlooking, and being overlooked, is a potential issue.


A South facing block with living rooms to the rear (North) is going to give the best results if you are looking for a passive solar house to minimise heating and cooling costs.


For a rear block you could be hit with extra costs for:

  • 15m plus driveway construction.
  • Extra utility costs due to distance from existing services.
  • Builders charging a restricted access fee in addition to the typical/normal advertised price.

Sewer and Drainage Easements

Easements are often run along the back fence of the original block.

A typical 2-3m easement can severely limit what you can build on the block, particularly when you might also have an easement to service the front block running through your block.

I have heard of sewer lines on subdivided blocks running down the middle of the block, so its important you check this before you buy!


As part of arranging the subdivision the sub-divider will often get planning approval for a type of house.

If that’s not what you want make sure you get the owners written agreement to the design you offer to buy.

It might even be worth making an offer subject to planning permission.


As I haven’t personally built on a subdivided block I may have have missed an issue you have experienced. If you think so why not leave a comment?

To better understand what you can build see Restrictions in the Blocks section


Covenant Removal

A previous post talked about restrictions placed on block by covenants

So you have found the perfect block. . . but it has a covenant restricting the amount of buildings to 50% and your dream plan will occupy more?

Removal of covenants can be tricky and it may be best to talk with a lawyer experienced in planning matters.

Typical process.

  1. Have a walk around the area to see if any other blocks have been changed which may be a precedent you can use.
  2. Be realistic about how much you want to change the restriction If the restriction is 50% then 60% development may be achievable. More than that and you are likely to get objections.
  3. Talk with the immediate neighbours to see if they feel your proposals are reasonable, as they are the most likely to have objections. They are more likely to object if they feel their amenity is lost. ( for example their sunny backyard is shaded by a large double storey building occupying most of the lot)
  4. Put in a planning permit to the council to change the covenant which will involve a fee. Make sure you put in as much detail as possible including any precedents in the area where other lots have been developed without any detriment to the area.
  5. The council will mail out to everyone that may be affected or who also has the same restriction on their title. Typically all the estate can be considered “beneficiaries” of the covenant as they either all have the covenant or benefit from it in some way.
  6. Wait a month to see if anyone objects. If anyone does object (inside that 28 day period), they have to put that in writing and advise why they object. The objection has to show why the “amenity” of their property (value, enjoyment and aesthetics) would be harmed by lifting the covenant.
  7. The town planners will consider whether your proposal really affects the neighborhood, and if they would normally approve the development. If there have been any objections, these will be considered to see if there is any merit. Objecting just for the sake of it (vexatious objection) is not acceptable.
  8. If you don’t get any success with Council then you can try court proceedings . . . but that could be a big bill.

Good luck!


For more posts about what you can build see Restrictions



When I worked for a drainage contractor almost every month I have to tell people that they are going to have to take down their shed, dig out part of their raised garden bed, or take up part of their paved patio.

Why? ……………because they have built them on top of a manhole on a drainage easement that needs to be cleaned or inspected.

How Common Are Easements

About 50% of properties will have a drainage or sewerage easement generally running along the back fence.

These will be shown on the title plan.

Between 5 and 10% of all properties will have a manhole within their property.

This will be used to access the sewer or drain for maintenance.

When buying a house block be very careful if you find a block that has an easement running from front to back, as this will severely restrict your options on what you can build.

Why are there Easements

Easements are a method of giving other people some rights over your property.

Examples are:

  • The right to have a pipe or other underground, or above ground, service laid under your property. The most common easements are for drainage and sewerage pipes. You will sometimes come across utility easements for water supply, electricity, telecommunications and gas.
  • Right of access, for example; to come onto your property and maintain, repair and replace the services.
  • Right to use a shared driveway

Although the person or organization having benefit of the easement has the responsibility to restore the land after maintenance and repairs this does not usually extend to rebuilding any structures such as sheds or replacing expensive paving.

Building on Easements

It can be difficult and expensive to be allowed to build any permanent structure such as part of your house over an easement.

The actual width of a pipeline easement will depend on the size and depth of the pipes, and on having enough room to carry out maintenance and repair.

Another factor is keeping the foundations far enough away that they don’t damage the pipe.

Do you check your  Title Plan?


To better understand what you can build see

Restrictions in the Blocks section


Building On Pipeline Easements (Or Close To)

Previous posts have talked about Sewer and Drain Easements but you build close to or over a pipe on an easement?


You must get permission from the owner of the easement to build on the easement.

Some easement owners won’t permit any building.

However some will allow certain works after a fee is paid.

This fee can amount to several thousand dollars particularly if you want to build right over the sewer.


The minimum costs are likely to be a CCTV survey of the pipe which could cost over a thousand dollars.

Additional costs may include either exposing the pipe and encasing the whole line in concrete, or re-routing the pipe and paying for the cost of establishing a new easement.

Getting the Design Right.

When building close to a buried pipeline, whether the building is in the easement, or close to it, the designer needs to ensure no loads are placed  on the pipe.

To avoid placing any load on the pipe the base of any foundation should be below the zone of influence of the pipe.

This zone of influence starts at the base of the pipe and rises at a slope of 1 in 1 to ground level.

In the diagram above

  • Foundation A is unacceptable The base is inside the zone of influence.
  • Foundation B is acceptable Even though it is the same horizontal distance from the pipe as Foundations A because the base is outside the zone of influence.

The base of the foundation is the lowest point of the foundation, that is the bottom of the slab, In the case of piers the base of the piers.

Building Over the Pipe

Some water authorities do allow building right over a pipe. in that case the base of foundations on both sides of the pipe needs to be outside the zone of influence.

Any beam or slab over the pipe needs to be designed to span between the foundations.


To better understand what you can build see

Restrictions in the Blocks section


Restrictive Covenants

Don’t think because you buy a block you can do what you like on it!

There are often restrictive covenants on land. . . . .That is “an agreement between land owners which may restrict how land may be used and developed“.

Who Is Involved?

The two parties to a covenant are:

  • The party that owns the land burdened
  • The party, or parties, that owns the land benefited by the covenant, which is likely to be either initially the developer, or the original landowner.

On a long established estate the party benefited will typically become your neighbours.

For example if there is a restriction on height of buildings your neighbour benefits from not being overlooked.

In this case if you want to extend upwards you will need your neighbour’s approval as well as planning permits.

Reasons for Covenants

There are many reasons Covenants are used, including to:

  • Protect views from being built up – most likely to be the original landowner if they still live adjacent to the site.
  • Protect the level and type of finish of all dwellings and boundaries within an estate – most likely to be the developer who wants the estate to look attractive to future land purchasers.
  • Protect the type of use that takes place on a site. No car repair and animal breeding are common.
  • Protect the level of development – single dwelling covenants are common, avoid if you may want to build a granny flat in the future.

The presence of a Covenant may only be indicated in ‘The Copy of Title’, or it may be included with your Section 32 or Vendor’s Statement. You need to be sure what restrictions are imposed before you buy.

What can you do about a Restrictive Covenant?

If you find a Restrictive Covenant on title, there are few courses of action you can take.

  1. Decide if the clauses are of benefit to you as they are likely to place similar restrictions on your neighbours.
  2. Pursue the removal of the covenant through legal channels which could be costly and difficult.
  3. Read carefully for possible ’sunset/expiry’ clauses on your covenant.
  4. Don’t buy if you don’t like the covenant, Just look elsewhere!


Also see Covenant Removal.

Remove, or Vary, a Covenant

Many properties come with covenants that restrict what you can do with the site.

Although you can try to Remove the Covenant you might have a better chance of success in getting a permit to vary it instead.

A couple of examples:

  • The covenant says ‘Only One Dwellings’.

If you want to subdivide the block you are less likely to get objections if you attempt to vary the covenant to be ‘No More Than Two Dwellings’. Neighbours will be less concerned about two properties than if the covenant was removed and they thought you may want to put 3 properties on the site or even a block of apartments.

  • The Covenant says ‘No Front Fence’.

If you are getting people walking across the garden you could look at varying the covenant to say ‘No Front Fence higher than 900mm’. Such a change would preserve  a relatively open aspect to a street while avoiding someone building a wall that makes their house look like a fortress.

Even with these changes there is no guarantee off success, but it is likely to improve your chances.

If you want to find some case law you could have a look at which provides examples of cases which have gone to court in Victoria.


Stormwater Discharge Point

One check that is often forgotten when buying a house block in an established suburb is how storm water is removed from the site.

Forty, or more, years ago when land was cheaper, it was not unusual for blocks to be quite large compared with the size of the house.

Disposing of storm water by allowing it to soak into the garden in the garden was acceptable. (This is still effective in sandy areas such as much of Western Australia)

As a result many properties were built without connection to a surface water sewer.

Modern Knock Down and Rebuild Problems

If you buy block  in an older suburb with the intention of subdividing, or demolishing and building a bigger house, you could have problems if you haven’t got access to a storm water sewer.

Disposal to a much smaller garden area probably won’t work.

In order to protect adjoining properties from overflows from your property the council are likely to make discharge to an approved point conditional on any development approval.

Dealing with the attendant problems if you plan to extend or subdivide a block without a stormwater discharge point can add thousands of dollars to your costs.


Possible options are:

    1. Soakwells. If you are lucky enough to have a sandy block soakwells may be a solution. Low cost.(see this link: Soakwells )
    2. Pipe to existing surface water sewer. This may involve negotiating with adjacent property owners. Very difficult to achieve unless the affected neighbours also want to subdivide. Very expensive.
    3. Discharge to Street
      Check with your council to see if this is permitted. A typical street connection will look something like this kerb outlet. Can be a reasonable cost if the block is above the road, or very expensive if the block is below road level Pumps and a detention tank will be needed (See these links Pumps and Detention Tank)


See Guide to Buying a Block for more information


Onsite Stormwater Dention – Why

If you want to redevelop or subdivide an existing urban house block, you might find that a planning condition is that you will need to provide On-site Stormwater Detention (OSD).

You may also find it is a condition on individual blocks on smaller subdivisions.

Why Is Onsite Stormwater Detention Needed?

Before development of towns and cities a large proportion of the rain that fell in an area soaked into the ground or flowed slowly across the land to a creek or river. When areas started to be developed two things happened:

  • More and more of the land was built on, or paved, which meant rain was unable to soak into this ground.
  • Stormwater drains were built to carry the rainwater quickly away from the houses to be discharged into streams and creeks.

Initially while Australia had a small population this didn’t cause too many problems.

Since the mid 1950’s and the rapid growth in population more and more land has been built on.

The result has been more and more water has been discharged surface water drainage systems causing overloading of the piped systems and flooding of the rivers.

In order to try and reduce flooding Planning Authorities are attempting to reduce rainwater flows from developments to a flows similar to an undeveloped site.

OSD On Large Subdivisions

If you buy a block on a large subdivision it is unlikely that you will be asked to provide OSD on your Block.  This is because large developers  as a condition of the overall development have to provide Stormwater Detention Storage for the whole development.

The way they usually do this is by making much of the open space they also have to provide as Ponds, Lakes or Wetlands, which can fill up during periods of rain and then slowly empty. (Now you know why so many developments have a reference to Water in their name)

Other posts will explain more about how the Storage Volumes are Calculated and will look at various storage options.

Guide to Buying a Block has lots of info like this on what to look for before you buy land.


Floor Space Ratio, or Plot Ratio

When you are buying a new house block it’s important you understand how much of the block you can build on!

One way in which NSW councils prevent Over development is by prescribing a ‘Floor Space Ration’ (FSR). The same principle applies in WA but is called ‘Plot Ratio’.

The FSR of buildings on a site is the ratio of  ‘Gross Floor Area’ to Total Site Area.

Gross Floor Area is defined as – The sum of the internal floor area of each floor of a building  measured at a height of 1.4 m above the floor.

It includes  habitable rooms in a basement or an attic.

It excludes:

  • Stairs
  • Voids above a floor in 2 storey properties.
  • Non habitable storage including basement areas
  • Vehicular access and car parking
  • Terraces / Balconies with outer walls less than 1.4 metres high, and

To calculate, you multiply the site area by the FSR ratio.

For example

For a 800sqm site and a FSR of 0.5:1

Maximum Floor Space = 800 x 0.5 =  400sqm.

See Restrictions for  more posts  about what you can do on your land



Habitable Rooms

What is a Habitable Room?

You see the phase in several planning and building documents with regard to things like Ceiling Height (see Room Height) and  Overlooking.

Well according to the Building Code of Australia (BCA)

A Habitable Room is ” A room used for normal domestic activities”

Habitable Rooms Include: 

  • Living / Lounge / Family rooms
  • Bedrooms
  • Television Room/Home Theater
  • Kitchen
  • Dining Room
  • Sewing Room/Study
  • Music Room
  • Playroom/Family Room
  • Sunroom

Habitable Room Normally Excludes:

  • Bathrooms / Ensuites / Toilets
  • Laundry/Clothes Drying Room
  • Pantry
  • Walk-in Wardrobe
  • Corridor/Hallway/Lobby
  • and “Other spaces of a specialised nature occupied neither frequently nor for extended periods.”


Also see  Overlooking