Contracts – Provisional Sums

All new house building contracts will have a section for Provisional Sums.

These are used for work that  MAY be required, but the builder can’t provide an accurate estimate at the time of signing of the Contract.

The main area  for provisional sums is related to foundations where the limited information obtained during the Site Investigation may not truly represent the conditions found over the whole foundation.

A coule of examples are:

    • A rock item may be included even if the site is clay. This caters for any large boulders that may need to be removed.
    • An amount may be included for concrete piers if the amount of fill on site is hard to determine.

So the total contract price reflects the cost of building the house the builder will put in his best estimate of the overall cost of the build.

The provisional sum  will reflect the direct cost  of  those items to the builder only. (Overheads are included elsewhere in the contract price)

For example with a typical provisional sum item for removal of rock…… The builder will often include a figure of say $2,000 for excavation, and removal, of rock.

If there is no rock the contract will be reduced by $2,000.

Alternatively if the cost of excavator, labour and transport was $3,000 the final price will be increased by $1200. ($1,000 extra plus overhead percentage on the extra, typically 20%)

The builder is only allowed to add any overhead for profit and administration, to provisional sum expenditure items where they are above the original estimate.

Did you have any issues with Provisional Sums on your build?

See similar posts in Contracts

 

Travel Issues

It’s a Saturday morning and your partner says “Why don’t we go and look at some blocks that have been advertised in the paper?”

So you jump in the car and in no time at all you are at the developers office.

“That was easy!” you say………….but how realistic is Saturday traffic compared with a future weekday commute?

Once you move you may find you are spending a long time looking through your windscreen at traffic!

Before you make a decision perhaps you need to try the traffic out:

    • Arrange to meet your partner straight after work and see how how long it will take to get home in rush hour. Twice as long?……….or four times as long!
    • If you are really keen, then get up at 6.00am, and drive to the site. You can then see how long it will take you to get to work.
    • A quick check might be to use Google Maps to estimate journeys for a few work days
    • You might  also try out the public transport.

Were you surprised how long it took to get to work after you moved?

See Blocks for more information on buying land.

 

Building On Clay Soils

Clay is a fairly common soil type.

Although it is quite suitable for building one issue is that some types of clays (‘Reactive’ or ‘Desicated’ clay) that shrink or swell depending on the level of moisture.

This can lead to the following problems:

Subsidence

Subsidence or settlement is when the building foundation drops, caused by the loss of support of the site beneath the foundations.

This is usually caused by shrinkage of the clay due to it becoming drier.

Typically this is due to tree roots spreading under the building and taking the moisture out of the clay.

Prolonged drought can also cause soil shrinkage beneath a building.

Soil Heave

Heave is the expansion of the ground beneath part or all of the building.

Expansion pushes the foundations, and thus the building upwards.

This is a photo of a boundary wall with inadequate foundations.

Due to soil heave the right side of the wall has lifted by over 100mm causing cracking of the mortar joints, and a brick.

Although the mortar joints have recently been repointed you can see they are no longer straight.

The most common cause of soil heave is building is when the clay becomes wetter and starts to expand.

Common reasons for the clay to become wetter are:

  • Water seeping down the side of the house (In areas of reactive soil a normal requirement is to have a 1m wide footpath round the house)
  • Poor site drainage (No drainage, blocked drains, or leaking water pipes)
  • Removal of trees (This means the drying effect of the roots has been removed)

A couple of danger signs of future soil heave issues for a new house build are:

  1. If building after several years of drought the soil may be excessively dry and therefore more likely to become wetter when the drought breaks.
  2. Removal of trees immediately before building.

Summary

There is no reason why you shouldn’t build on clay soils but you need to ensure that;

  • You have chosen an appropriate construction method (Brick Veneer is usually better than double brick)
  • There will be minimal soil moisture change when the house is built. (see this link:  Protecting Your Slab)
  • If you need concrete piers see the following link: Building on Fill.

To find out more about the soil on your block click on this link: Soil Classification

 

 Lots more information in the anewhouse at this link: Guide to Buying a Block

To find out what soil is on your block see this link: Site Investigation

 

Battleaxe Block

Have you seen a ‘Battleaxe Block’ advertised and wondered what it is?………….Well it is a block that only has a 3-4m frontage on the street.

Often these blocks are as a result of subdividing a long block with the rear block then becoming the ‘Battleaxe block” – coloured red, as in this plan.

In the plan the existing house has been retained.

You will also often find cases where the original house has been demolished to allow 2 blocks to be sold at the same time.

Another way of splitting a large block is a ‘Small Strata’ Development. (see this link: Small Strata)

What  are the issues with Battle Axe Blocks?

Driveway

To get access to the site you will require at least 20m of driveway and perhaps a turning area. This will have a substantial costs. I would allow at least $600/m run of driveway for a temporary gravel driveway during construction and for final concrete at completion.

You may save on this cost by going for a Small Strata Development with a common driveway, instead of a Battle Axe Block but:

  • Getting agreement from your neighbour to use the access for the construction can be difficult.
  • In my experience the best way to have good relations with neighbours is minimise causes for dispute. Sharing a driveway means that your parking options are limited.
  • Looking after the shared driveway is like some of the ‘Community Title’ issues (see this link: Community Title )

An advantage of that long driveway is if you put a gate with a childproof lock at the front it gives a safe area for toddlers to play.

Additional Service Costs

You will be need to bring in some if not all of the following service for an extra 20-30m.

  • Power.
  • Phone.
  • Water, could be two services if you want recycled water.
  • Gas, if it is available.
  • Storm water drainage, can be a problem if inadequate fall and property drains to road.
  • Sewer, usually this is at the back of the block but check before you buy.

Additional Building Costs

I have heard additional building costs of more than $15,000 for battleaxe blocks because of a restricted site (see this link to find out more: Restricted Site)

In Conclusion

I am not saying don’t buy a Battleaxe Block, just make sure that you think carefully about the implications.

What issues have you found with Battleaxe blocks?

 

Lots more information in the anewhouse Guide to Buying a Block for only $4

See Blocks for more information on buying land.

 

Developer Rules/Guidelines

Most developments have some sort of design rules placed on the blocks they sell.

For our last house the only rules were;

  • Only one house to be built on the block.
  • All side and rear fences must be green colorbond.
  • No second hand houses to be moved onto a site.

As far as we were concerned none of these were any problem.

Strict Guidelines

Some developers guidelines however can be very stringent which can add considerably to the cost of your build and limit what you can do with the block.

Examples of Developers Guidelines include:

  • Minimum and maximum size living space.
  • Minimum setbacks from each boundary.
  • Maximum heights.
  • Facade must not be entirely brickwork and bricks must be single colour.
  • Limited choise of external paintwork colour.
  • Specified Roof colour, material and/or slope.
  • All houses must have minimum 450mm eaves.
  • Fencing must be masonry or timber.
  • Garage doors set back from front facade.
  • Landscaping must be finished within 6 months of occupation.
  • All outbuildings (sheds) must be constructed using the same material as the dwelling.
  • Restrictions on which builders you can use.

I’m not saying this is all bad.

Lots of people like these sort of rules as it prevents their neighbours building anything outlandish and spoiling the look of the street.

Just make sure you are happy with the developers guidelines before you sign on a new block!

Did your developer have any unusual guidelines?

See Restrictions for more limitations on how you develop your block.

 

Buying A Sloping Block.


It doesn’t take much of a slope to mean that costs will increase.

For the last house I built, in 2005, a 0.8m slope over a 26m wide by 32m deep block added $4,800 to the cost.

That’s for much less of a slope than the block in the picture.

The extra cost was for some cut and fill ($2,900) to level the site under the slab, and about 12m of 450mm high timber retaining wall ($1,900).

Much more of a slope and the costs can really shoot up.

Reasons for Additional Costs

As well as cut and fill costs you could have:

  • Drop Edge Beams – A sort of retaining wall as part of the foundation to make sure that the fill stays under the foundation.
  • Concrete Pier, or Screw Piles may be needed because the different depths of fill under the slab will have varying strengths.
  • Higher Strength Slab – Needed to span between the piles.
  • Extensive Retaining Walls – Once Retaining Walls go above 1m high the costs increase significantly.

One advantage of double storey houses on slopes is that the additional cost of foundations will be lower than those for a single storey house of similar total floor area due to the smaller foundation area.

Steeper Sites

For really steep slopes you may need to go for a Split Level Home or even build on ‘Stilts’.

Either way you are definitely going outside the typical project builders territory and probably looking to get a custom builder and architect involved in the house.

So why build on a slope?

Well for many people its a view, and means you may only be overlooked on one side of the house.

Without a view and I would only be looking at building on a slope if the block was significantly cheaper, to offset the additional costs.

For Similar Posts see Choosing Blocks

Or see Understanding Retaining Walls

 

Understanding your Survey Plan

I’m used to look at survey plans but I do understand that most people struggle to understand them.

Here is a quick guide to help you understand the survey plan for your new house.

The plan below shows a survey plan, with a North Point, has been provided.for the block previously mentioned in the Title Plan Post. It doesn’t include the easement to make it easier to see the other details.

The bearing and length of each boundary are the same as the title plan in the format.

For example the North boundary is at bearing of 92 degrees 0 minutes 15 seconds (92° 00′ 15″) and 38m long.

The footpath along the front of the block and the nature strip crossover (constructed by the developer is shown, as well as an electrical pit.

TBM stands for Temporary Bench Mark.

This means the surveyor will use this feature as the level on which all other level information such as slab levels will be based.

It is normal for the TBM to be set at a round number typically either 10.000m or 100.00m.

Usually the only time the TBM’s actual height will be the correct height above Sea Level (Australian Height Datum) is when there is a risk of flooding and the floor level will need to be above the 100 year flood level.

Once the TBM has been set the surveyor calculates the surface levels of the block.

This is shown by contours, (shown dashed) which are lines of equal height.

The normal contour interval for residential block surveys is 0.2m intervals and each contour is labelled with the height it represents.

In addition to the contours the surveyor will show spot levels at the corners and sometimes in the middle of the block. (These are marked with a ‘+’ and a height)

From this drawing you can see:

  • The lowest part of the block is the South East corner at 100.00m
  • The highest part of the block is the North west corner at 100.85m
  • The block slopes upwards from the front at approx 0.53m. (around 1 in 70)
  • The block slopes upward in a Northerly direction at approx 0.30m (around 1 in 60)
  • As the contours are roughly similar spacing from each other the slopes are fairly constant.

 

In summary although there is a slope on the block it isn’t too severe so the site costs for dealing with the slope could be around $4- $6,000.

 

For more see Blocks

 

Climate Change Protection

In the thirty years I have been living in Australia the climate seems to have changed. . . . . and not for the better.

  • More severe storms.
  • Worse Bush Fires.
  • More floods.

So how does this affect you when looking for a new home?

Well there are now some websites that provide some information about risk.

Here is one I tried out

climatevaluation.com

This site claims to be able to give you information for any location worldwide.

Here is the summary of the (free) information for my current address

B means MODERATE RISK – Risk may lead to higher insurance costs.

The other possible results would be:

A LOW RISK – Risk may be insurable at reasonable cost.

or

C HIGH RISK – Insurance may be high cost or unavailable unless adaptation actions are undertaken.

You can also pay $400 for more detailed information.

Conclusion

Knowing the area well I would say the risk level seems reasonable.

If I was looking to buy again in an area I didn’t know I would certainly want to consider Climate Risk.

 

NB. I have no connection with climatevaluation.com and have not been paid for this post.

 

Water Views? or Flood Risk?

Lots of people want water views ………….but if the water view is a River, or even a Small Creek, there can be a flooding risk.

The quiet creek in this photo is about 300mm deep and 3m wide. After a couple of days of rain it can be 3m deep and 30m wide.

The 2022 Floods in NSW are even affected properties that were km’s from rivers.

Generally the planning laws say the floor must be above the 1 in 100 year level……………I don’t think that’s enough.

  • The 1 in 100 year flood level is an estimate only. How often have we seen in the paper two 1 in 100 year storms in a matter of weeks. Over the past couple of weeks I have heard about 1 in 500 year floods!
  • Sometimes the data used to calculate the flood levels is based on as little as 10 years worth of records. In Australia flood levels have only been monitored on many major rivers for less than 100 years.
  • River and stream catchments change over time. This is normally by additional buildings which increase the rainfall runoff into the stream so flood levels tend to rise.
  • Global warming increases the power of weather systems meaning that storms are likely to be more severe in the future which means higher flood levels.

Although I have had houses close to rivers and streams its always been more than 3m above predicted flood levels.

If you are tempted to buy land close to a river have a look at what, if any, flood insurance you can get. That may give you pause for thought!

Do you think a river view is worth the risk?

For Similar Posts see Choosing Blocks

 

Placing Your House On The Block – 10 Things To Consider

There’s lots to think about when you are positioning a house on a block.

Here are some things that you should consider when comparing blocks and then deciding how to place your house,

    • Statutory Limits There are usually the following limits on where you can place your house:
    • Local Council Setbacks (the rules should be on the council website, it may refer to the building envelope)
    • Sewer or Drainage Easements (check your title documents for these)
    • Driveway Crossover Many blocks now come with the driveway crossover already constructed which causes further restrictions unless you want the expense of removing the crossover and constructing a new one in a different location.
    • Take Advantage of the Sun My aim to get most of the main rooms facing North for a solar passive performance and which helps with the energy rating performance (A good orientation can boost the environmental rating by at least one star).
    • Avoid Shading I like to place the house fairly close to the Southern Boundary so that the I can have a garden on the sunny side of the block which you can see from those North facing rooms. The wider garden also helps prevent shading from the house next door.
    • Overheating from Afternoon Sun Avoid or at least minimise West facing windows.
    • Welcoming Entrance Front doors should be facing, and clearly visible from, the street . . . it looks more welcoming and improves security.
    • Outdoor Entertaining Areas Decks and alfresco areas with a westerly aspect are good for having a beer in the evening while watching the setting sun.
    • Kitchen Views In our last house the kitchen window had the most interesting view. . . as that is the one you find yourself looking out of the most.
    • Storage Areas Do you want to store a caravan, trailer or boat on the site.
    • Pets If you have a dog does it have somewhere to run around without damaging your main garden? and somewhere where it can sleep away from rain and summer sun?

 

What do you think is important when placing you house?

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