Published 27th November 2015
Updated 05 September 2022
Copyright 2022 - Perth Soakwells Pty Ltd
Soakwells & Stormwater in Perth, Western Australia
A brief overview of Perth's new homes
Perth has shown fantastic property growth throughout the last decade. In that time there has been a shortage of vacant land where the supply has fluctuated placing prices for land under pressure. For anyone who purchased and held a property over this period, there has been a significant capital gain. Ultimately, the influx of population, booming industries [ now winding down] created a large demand for builders of new homes. Over this time many builders had come and gone but the steady few remain and are a part of the Perth home building landscape for the foreseeable future. The majority of Perth builders cater to most aspects of the building process from the shell to the carpeting, painting and landscaping. However there are a few areas where costs can significantly be saved when a client elects to arrange these themselves such as soakwells.
In Western Australia the general approach to stormwater Perth by most councils is to have the stormwater be retained on site. This does not mean that water must be stored on site. Rather it refers to prevention of stormwater from spilling onto surrounding properties. Soakwells cater to that need by diverting stormwater underground where it makes its way into the water table.
So when it comes time to sign the final contract with your builder remember there are a few areas you can save costs, especially by contacting Perth Soakwells to install the soakwells. Consider the following 10 tips to get the most out of the process:
Soakwell Tip #1 - The Best Advice
As mentioned above the best advice is to confidently arrange the stormwater or soakwell system yourself. The main reason for this would be cost savings. While builders charge in the region of $6000 to $8000 for a stock standard soakwell installation, we could provide the very same service for significantly cheaper. Additionally, we are the main source for soakwell installations for Perth's best builders. You would receive the very same service and installation however at a saving to you.
Soakwell Tip #2 - Install Soakwells at slab stage
Arrange with the builder to have Perth Soakwells install your soakwells at slab stage while excavator access is still available. At slab stage it is most common to install concrete soakwells. The reason for preferring concrete soakwells over poly soakwells at slab stage is that other trades may excavate the soakwell area with excavators which would damage poly soakwells, but concrete soakwells would not be easily damaged. This avoid headaches for a few reasons:
- Builders tend to advise that soakwells can be installed at handover, however in MOST cases this is not possible once the house is handed over due to sewer/gas/water/Telstra services and pipes all located in the area originally reserved for soakwells.
- If both your soakwells are located in the front do insist on having them installed at slab stage. We can return at roof stage to install the stormwater connections.
Take the above for example. With both tanks at the front of the property it must considered that once the house is built this installation will be nigh impossible especially if services such as electricity/gas/water/Telstra and sewer are in those locations.
In the event that your new home has been handed over to you, it may be more viable to install polypropylene soakwells. Polypropylene soakwells are far more configurable which is an advantage if services such as power, gas lines, water pipes and sewer have been installed.
Soakwell Tip #3 - Locate the soakwells in rear and front
It is far better to have a shorter flow distance from the roof to the soakwells. Having a soakwell in the rear and the front ensures that water will flow from the downpipes to the soakwell with minimal congestion and maximum flow. Additionally, there is less saturation in a single area on the property which steadies the absorption of your soil which will provide better performance for your stormwater and soakwell system.
Soakwell Tip #4 - Avoid placing soakwells in future pool locations
Major soakwell tip in Perth Western Australia! In case you have not yet noticed, Perth get's pretty hot in the summer months! Many homeowners choose to install a pool to allow for that sweet summer cool off. Unfortunately we received dozens of calls a year from disappointed homeowners that have decided to install a pool but upon excavation have discovered soakwells in that exact location. The usual request intimates what the cost would be to "quickly" move a large concrete soakwell. The client is always surprise to discover that it can be quite costly to move a soakwell.
- If we no longer have excavator access then we need to either: jackhammer the soakwell out manually or we need to hire a crane to lift the soakwell out and re-install it in a new hole. This can easily cost between $1500 to $3500.
Remember, before installing soakwells, always consider where the future pool or spa may go, even if you never intend to do so. If you ever sell the house you would do the next homeowners a gigantic favour by planning ahead.
Soakwell Tip #5 - Have a stormwater prelay under the garage
If you have a house which is built on the boundary of your property, always ensure to have a stormwater prelay under your garage slab before the garage concrete is poured. The same principal is extended to your reticulation. Without a stormwater prelay we may not be able to direct the water from behind the house to the front. Even if we can, the installation becomes considerably more expensive and difficult. The smart and thoughtful builder ensures that there are prelays under the garage slab as per the pic below. Note: the pipe should be at the right height and angle otherwise it may be useless to us!
Soakwell Tip #6 - Choose an open grated Soakwell System
You may have passed hundreds of houses but never taken note of the type of connection beneath the downpipes. You may have never noticed the connection beneath the rainwater pipes of your own home! Not only does the connection provide a particular look to your home, it also provides a mechanism of funneling stormwater from your downpipes into your stormwater or soakwells system.
The collar and grate system or open grill system has been in used for several years, pioneered by Perth Soakwells Pty Ltd. In the heavy storms that occurred a few years ago, Perth Soakwells was the only installer to have ZERO complaints from their clients. Among a number excellent reasons would be the open grate system. Read more about grates vs direct stormwater systems.
Soakwell Tip #7 - Compaction of soakwells & stormwater, Perth
After a soakwell installation, the empty cavity around and above the soakwells get filled back in with soil. This is commonly referred to as backfill in the stormwater and soakwell industry. Once the sand is backfilled around and above the soakwell the installation is complete.
What many homeowners mistakenly do is to arrange installation of paving and landscaping without considering the future compaction potential of their soakwells. Essentially you should be aware that when sand is filled back into a soakwell hole, the sand particles are mixed with pockets of air. When it rains the stormwater will exit the soakwells and squeeze the air through the soil which causes the sand to sink and compact. It is of utmost importance that the client waters the soakwells or stormwater for a few hours or days after the installation. A rainfall prior to paving is ideal as the stormwater will do much of the compaction for you. We can also compact the area at backfill intervals at a charge due to the time and care it takes to do so. In our professional experience simply grabbing a hose or sprinkler to saturate the soil for a few hours could assist. This should then be followed up by proper compaction by a qualified and experienced paver, landscaper etc.
Soakwell Tip #8 -Soakwells and the Angle of Repose
When we excavate for soakwells in Perth, Wester Australia, we always ensure to take into account the angle of repose. The angle of repose or the critical angle of repose, of a granular material is the steepest angle of descent or dip relative to the horizontal plane to which a material can be piled without slumping. At this angle, the material on the slope face is on the verge of sliding.
In other words, we remain the correct distance away from your dwelling to avoid undermining the footings of your home. We encounter numerous repair works where soakwells have been installed too close to the footings of the house. In some cases this causes moisture issues but in most it has a serious effect on the structural stability of the home.
Soakwell Tip #9 - Rock breaking Soakwells in Perth,WA
When arranging you soakwells and stormwater system, always take into account the type of soil your property consists of. Sandy soil is conducive to soakwells and a low cost installation. Rocky soil however can create reduce drainage efficiency and certainly increase soakwell installation costs.
- If you have rocky soil, try to install wider soakwells rather than deeper soakwells
- Take into account that breaking rock will incur extra charges so budget according for soakwells in rocky areas.
Soakwell Tip #10 - Soakwell Perth Storage Volume
The largest deciding factor on whether or not your soakwells will cope with a particular size storm is storage volume. A soakwell's storage volume determines how much stormwater it can store during a heavy rainfall while the water dissipates into the soil. Once the soil surrounding the soakwells is saturated the storage volume will determine whether or not the stormwater continues being held underground or whether it starts overflowing above ground. Larger volumes will always be a benefit in larger storms, however, the costs may increase due to additional excavation, materials and labour.
With concrete soakwells, the storage volume can easily be maximised to 4400 litres with an 1800x1800 concrete soakwell. On the other hand, polypropylene soakwells Perth can be configured up to any volume due to its modular design. However, the material and labour cost is higher on larger volumes due to the amount of modules it takes to assemble to achieve larger volumes.
In this article we shared some tips on stormwater and soakwell installations. We pointed to several factors that should be considered when building a new home. The different hints we provided were accumulated from servicing hundreds of clients with their soakwell installations and we hope this has been of some benefit to you.
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