Blocks – Page 5 – A New House

Saline Ground Conditions

“Valley of Salt” – Salinity in the Western Australian wheatbelt near Bruce Rock, WA. photo by CSIRO

Salinity doesn’t have to be as bad as in this photograph to cause problems in new homes.

It’s also quite common for land that has not got salinity issues to develop salinity over several years.

Building Problems Due To Salinity

Problems can range from cosmetic through to significant structural issues.

Efflorecence This is the white powdery deposit sometimes seen on brickwork or concrete. Sometimes it is caused by salts in the materials themselves, (See this link Efflorecence)

Breaking Up Materials If salt is carried into the wall be water and then dries it will form crystals inside the bricks, mortar, or concrete. These crystals can form internal pressure on the materials causing the external surface to crumble away.

Acid attack Acids can be formed that will increase the porosity of concrete and reduce its strength.

Increased Steel Corrosion A wet saline solution is likely to result in corrosion of concrete reinforcement and Brick Ties.

Solutions

Provide a Damp Proof Membrane under the slab.
Make sure the Damp Proof Course detail is effective; and is an appropriate height above ground level.
Check the land slopes away from the house.
High quality concrete including:
- Low Water/Cement Ratio, with no added water on site.
- Proper Curing procedures.
- Sulphate resistant cement and/or higher strength concrete.
- Concrete well vibrated to remove entrapped air and ensure high density in and around the reinforcing and formwork.
- Increased concrete cover to steel reinforcement.

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 restrictivecovenantsonline.com which provides examples of cases which have gone to court in Victoria.

Potential Acidic Sulphate Soils

Look to buy a block on a coastal plain, alongside a river, or a reclaimed wetland and you may see the area described as Potential Acidic Sulphate Soil (PASS).

Well PASS doesn’t mean OK!

Why, And Where It Occurs

These types of soil generally occur in areas which were flooded by seawater within the last 10,000 years.

During that time sediments containing iron and organic matter were deposited. Bacteria then living in the sediment was able to produce hydrogen sulfide which then reacted with the iron to form iron sulfide (pyrite).

This Australian Gov’t map shows coastal areas with a risk of PASS.

Acicidic sulphate soils have however been found in inland areas such as along the River Murray.

Problems

Draining the Soil

Pyrite is chemically stable unless it is exposed to air; such as when it is drained, or excavation takes place. (or even a prolonged drought)

Exposure to air means the pyrite oxidises and produces sulphuric acid and a range of other chemicals including the toxic hydrogen sulfide gas.

Release of the suphuric acid is likely to cause significant environmental damage over long periods as the strong acid can be released from soil for more than 50 years from the original exposure.

Because of the environmental issues all Australian States have management controls for areas of potential acidic sulphate soils

Damage to Foundations

Acid released from the soil can attack both the concrete, and the steel reinforcement within the concrete weakening the house foundation and the cement within the brick walls

Low Load Bearing Capacity

Many potential acid sulfate soils are weak clays that have not fully consolidated, and are likely to further subside or settle.

Precautions When Building

Deep, expensive, piles will normally be required to support your foundations.
Sulphate Resisting Cement should be used in all concrete.
Extra care will need to be taken to ensure all concrete is protected from groundwater by a heavy duty plastic layer.

Tiger Tails

Buy a block near overhead electrical cables and you may need ‘Tiger Tails’ during the build.

These are plastic tubes that fit over the cables and provide mechanical protection and visual warning on power lines and conductors.

Getting ‘Tiger Tails’ installed isn’t cheap and can be in the order of $1000/month.

A twelve month build and that’s $12,000.

It sounds a lot as the tiger tail itself is relatively inexpensive, but the cost can include:

Cherry pickers and operator.
Traffic Controllers.
Area power disruption.
Notifying surrounding users during disruption.
Suppliers Profit.

So when you start looking at blocks, Look Up and remember the potential extra costs!

Also see What’s On The Nature Strip

Chinese Lucky, and Unlucky, Numbers

I see from the papers that a significant number of properties are bought by Chinese Investors.

Also I have noticed many visits to my web site are referred from Australian based Chinese language website oursteps.com.au

So for all my fellow Gweilos’ (Ghost men) here is a quick guide to checking if the street number of the new house block you are buying is, or isn’t, auspicious.

Best Number is 8 八, which signifies Money

Could add thousands to your house price!

Worst number is 4 四, when spoken sounds like Death

Get in some lifts in china and you will find no fourth floor, or 14th floor!

Auspicious Numbers

3 三 – The Mandarin word sounds like “life”.
9 九 – Sounds like the phrase longlasting, also associated with the emperor.

Unlucky Numbers

5 (五 Associated with the word “Not”
13 – Although a Western Superstition this has been adopted by some Chinese

Combination Numbers

A repeated auspicious number like 88 is extremely auspicious

The first number can multiply the effect of an auspicious number – 28 means “Double Money” and 38 means ‘Triple Money’.

5 can negate the effect of an inauspicious number so 54 can become ‘Not Death”

Also check out some Aussie Feng Shui

NEIGHBOURS

Would you worry if you saw this guy (from Jim’s Jihad?) mowing the lawn next door?

Unlikely. . . but it does illustrate the fact that neighbours can have a big effect on your enjoyment, or otherwise, of your house.

In fact 20% of us have fallen out with a neighbour in the last 5 years, and only 1% said all their neighbours were great.

Before Buying a Block

If you are buying on a new subdivision who your neighbour will be is always a lottery . . . . so corner block have always been attractive to me as it means one less neighbour.

If I was looking at a vacant block (or Knock down rebuild) in an established suburb I would aim to make visits:

During the middle of a working day to check for barking dogs.
Mid to late evening to check for loud music.

At Selection/PreStart

If you want better sound proofing two things you should consider are:

Smaller Windows – As solid walls have better sound reduction than Glass

Double Glazing – Much better noise insulation than single panes

See Noise for more posts

Photo courtesy of neighborshame.com where you will find more bad neighbour photos.

Reasons to Re-Build

Knock Down and Rebuild, or Renovate?

It may be the only house you can find in the area you like is dilapidated, like this one.

You may already live in the house but it no longer suits your family’s needs.

If the house is un-renovated, and over 40 years old its going to need a lot of effort to incorporate modern features that people now expect.

Renovate

If the existing house has a preservation order, or the area has a heritage overlay you may have no choice but to renovate.

Some older houses that have a lot of character means renovating and extending may be a better way to go. Examples would be some California Bungalows, Victorian Cottages and Federation Homes.

Just remember that you will probably want to include things like:

En Suites
Walk In Robes
Large Island Kitchens
Air Conditioning
Good Insulation
New Electrical Installation

Costs can easily reach $3,000 per sq m as access will be extremely difficult and the renovation often involves reducing the existing house to little more than a shell.

Knock down and Rebuild

If the house has few redeeming features and the existing layout makes it almost impossible to reach a great outcome then maybe your money would be better invested in a Knock Down and Rebuild.

You may find a project home builders can build a new home for $1,500- $2,000 per sq m. Even using a custom builder you may find the cost cheaper than the cost of renovations with fewer compromises.

You really have to spend some time on research before you make a decision.

A Final Thought

A house is about Your Heart, the Block you buy, or own, is about the Location.

Unless I really loved the house with all its foibles I would rebuild.

See Blocks for more posts

Pre-Wetting A New House Block

Reason For Pre-Wetting

If you are Building On Clay that is dry there is a risk of Soil Heave.

This is due to expansion of the clay if the moisture level increases with particular risk factors being:

Building after a long period of very dry weather when large cracks in the surface are visible.
Knock down and rebuild projects where there is a risk that part of the new foundations are on drier land than other parts.
Where there are trees, or trees have recently been removed.

To minimise the risk there is often an Engineers requirement to pre-wet the site to stabilise the moisture content.

Pre-Wetting Requirement

A typical requirement is to run sprinklers for 2 hours a day for 8-10 days which should increase the soil moisture to a depth of approx 1m.

Then the fill/construction pad below the slab should be laid within 2-3 days,

You are aiming for the equivalent of 20-25 mm of rainfall a day (20-25L/m2) The intention is on each day to thoroughly wet the top layer of soil and fill all the cracks with water without actually waterlogging the site.

For maximum effect the best time to do the pre-wetting is the late evening to minimise evaporation.

I have hear of builders saying the pre-wetting isn’t needed. Don’t accept this without soil moisture tests that have been accepted by the engineer who made the original requirement.

Effectiveness of Pre-Wetting

Although pre-wetting will minimise the risk of Soil Heave

It doesn’t mean that good foundation design can be neglected.
Letting the site moisture content stabilise through a winter, after removal of buildings/trees, is likely to be more effective.

See Ground Conditions for more Posts

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.

Options

Possible options are:

Soakwells. If you are lucky enough to have a sandy block soakwells may be a solution. Low cost.(see this link: Soakwells )
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.
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

Access to Rear

With the narrow blocks that are becoming more common you see a lot of new houses built right to the side boundary on both sides.

In some cases that can’t be avoided, but I think there is a real advantage in buying a block with enough room for a path on at least one side of the house, preferably both sides.

Here’s some reasons why:

There will be extra costs for special wall and roof details, constructing foundations, and building walls on the boundary.
You might have ongoing property maintenance issues if you fall out with your neighbour.
If you need to do some gardening you can avoid taking top soil, plants and other dirty things through the garage, or even the house, if the garage doesn’t have a back door.
Many properties have drainage or sewerage easements with a Manhole (or in these politically correct time an access pit). If the council/water authority needs access you may need to take time off work rather than just leave a gate open for the day.
If you have a dog in the back yard then looking through a gate helps to stop them getting bored while you are out at work.
If you want a detached property why have it looking like a terrace?

Perhaps there are some advantages of building to the boundary. If you have found any let me know.