In Western Australia subdivisions are usually completed with retaining walls in place on the boundary so that all blocks are level.
For the rest of us if we are faced with a sloping site a retaining wall may be needed before you can build…………..but who pays?
Here are a few examples
Block A is sloping down towards the boundary and Block B is fairly flat
Block A has to build up their block and should be the only one to pay. The wall should be within their block.
Block A is fairly flat and Block B Falls away from the Boundary
Block B has to excavate their land and should be the only way to pay. The wall should be within their block.
The slope affect both Blocks A and B
As one block has to be build up and the other has to be excavated both should share the cost. This however can a fairly complex with some of the issues being:
Should the overall cost be apportioned if one site has to be built up by 1m while the excavation needed is only 0.5m.
The location of the wall particularly on slopes.
Fences on the wall
What happens if you are keen to build but the other block is unsold or the owner is in no rush to build.
Each block having their own wall may be a solution, however these can’t be too close together (See this link for more: Retaining Wall) which may be an issue if you need to site the house near the boundary.
In cases like this you really need to make sure your lawyer sews up a watertight agreement on retaining walls before you buy the block.
In the old days agricultural drains used to be constructed out of short lengths of clay pipe butted together without proper joints. The water seeped into the pipe through these butt joints. If you are building on a demolition site you may still come across these pipes.
Nowadays agricultural drains come in two types:
White slotted UPVC pipes with longitudinal slots which come in straight lengths (usually 6m long).
Black corrugated UPVC pipes with lateral slots that come on coils of various lengths.
For domestic jobs the black corrugated coils are probably the easiest option.
Some people confuse concrete with cement, but cement is just the ‘glue’ which holds the other constituents of concrete together.
There are a range of different cements but these are the three you will most commonly come across:
General Purpose Cement
This is consistent, versatile and cost effective which makes it a good choice for most building works. It can be used for Domestic concrete slabs, driveways and footpaths
Trivial Fact -You may hear standard cement referred to as Portland Cement – This is because the finished concrete has an appearance similar to stone quarried from Portland in England.
Sulphate Resisting Cement
Sulfate Resisting Cement is a blended cement designed to improve the performance of concrete where the risk of sulfate attack may be present. It also provides improved durability for concrete, and the steel reinforcement, in most aggressive environments,
Although it has an additional cost it is best for:
Geothermal areas and soils containing sulphates
Area that are frequently wet such as concrete swimming pools
Rapid Set Cement
Normally found in dry premixed concrete mixes. This is a cement with various additives that speed up the reaction to give an initial hardening within 15 minutes.
Any speeding up of the cement reaction time leads to lower final strength. This makes this product good for things like setting fence posts………… but NOT for significant structural applications.
Water Cement Ratio
One of the most important issues with cement is ensuring the ratio of water and cement is correct as this affects both the final strength and the durability. For instance:
Water cement ratio 0.5 (10L water to 20kg cement) is needed for high strength 35MPa.
Increasing the Water cement ratio to 1 (20L water to 20kg cement) will reduce the strength to 10MPa.
To ensure they don’t add too much water premix companies usually measure the water content in the sand and gravel piles and reduce the water content accordingly.
It’s not a new house but it is architecture and my wife or I use it every day.
It’s the footbridge at Footscray Railway Station.
Looks fairly impressive and very modern with its round shape………….So why is it a Fail?
Well you would think that one of the main purposes of this bridge would be to keep you dry as you walk across it on rainy days.
This is where it fails, most of those transparent panels you can see in the roof are in fact steel plates with lots of holes drilled in them.
Consequently when it rains you get as wet walking across the bridge, as if there was no roof!
Not only that but these panels are over the stainless steel handrails on the stairs. If you stumble on the stairs its no use relying on grabbing the rail as with the water streaming down them they are as slippy as ice!
A triumph of architecture over practicality! A truly Epic Fail!
Some small builders may suggest they can package build a house cheaper for you if you become an ‘Owner Builder’*.
*Not be confused with True ‘Owner Building’ where you have the skills and propose doing a lot of the work yourself
Here are 8 reasons why you should think very hard about doing this:
You remove the protection of the standard building contracts.
The whole exercise is about removing responsibility from the builder if this is their attitude at the start how confident are you they are going to take responsibility for any problems during the build..
Do you fully understand the responsibilities and risks which can include extra costs that can blow your budget.
Do you have all the knowledge, skills and time to manage the build properly.
You will have to take a course (May be available on line) which is going to take time. This will only give you the most basic understanding of the process.
Most banks are very reluctant to lend to owner builders so finance is going to be an issue.
You won’t have the advantage of any of the standard builders guarantees which means that if problems arise later you will have to meet the full cost.
When you want to sell many people can be reluctant to buy an Owner Built House without guarantees.
I have heard of several cases where this type of job went wrong but it may be successful for you.
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 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.
A North Point has been provided.
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. Its 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.