What is Trenching

Construction projects involve different types of excavation or earthmoving activities. Trenching is one of these.

What is Trenching?

Trenching or trench excavation is the creation of a narrow cut or cavity under the earth’s surface. When you dig a trench, the length of the excavated area typically exceeds the width. If the depth is less than six metres, the trench is considered a shallow trench. Meanwhile, excavations exceeding 6 metres are deep trenches.

When are Trenches Dug?

Trenches are an essential part of the construction activities or maintenance of any site or infrastructure. Below are situations that call for digging trenches:

  • Installation or replacement of drainage, gas, power, or sewer lines
  • Building strip footing or foundation
  • Installation of sprinkler systems
  • Formation of retaining walls

Using a trench digger speeds up the process significantly, reducing costs. There are different sizes based on the type of job.


What are the Hazards in Digging Trenches?

Digging trenches poses many safety hazards. These may include the following scenarios:



A trench may collapse because of a poor structure or support system. Cave-ins can trap site workers under the ground and cause serious bodily injuries and asphyxiation.


Hit Buried Services

When support systems are not properly installed, they can hit power cables, gas pipes, or water mains. If such accidents happen, they may cause electrocution, burn injuries, and exposure to hazardous gases. They may also temporarily interrupt utility services in the affected areas, this is why the owner or person in charge of any site must contact dial before you dig or hire a pipe locator before any digging proceeds.


Slip, Trips, and Falls

Lack of proper fencing and safety signage may lead to people, machines, and other objects falling into the excavations. Poorly installed access equipment like ladders can also make it difficult to climb in and out of the trench.



A broken water pipe or heavy downpour can flood the inside of the trench. If the trench is shallow, water can reach and flood the construction site.


Collapse of nearby structures

Excavating close to a building can weaken its foundation. If continued, it may cause the structure to collapse.


Falling loads

Excavated dirt may fall into a trench and crush people working underground. It is recommended to disallow working inside the trench during excavation to avoid such instances from happening.

For your excavation and earthmoving projects in Perth and West Australia, hire Dobson Excavations. We offer a wide range of services and high-quality equipment for your next construction project. Our team of experienced contractors will ensure that your project is completed safely and promptly.


Contact us here for a quote or to know more about our services.…

Steps when building a New Concrete Driveway

A concrete driveway not only brings a functional element of your property but also has an important visual function impact the curb appeal of your property. Building a new concrete driveway needs to follow a well defined process.

Why Build a Concrete Driveway?

Concrete is a durable and weather-resistant paving material, so it’s a popular choice of material in driveway construction. It also needs minimal maintenance and is easy to repair.

Constructing a concrete driveway on your property allows you to create an attractive exterior on your property. While concrete possesses a basic grey colour, decorative treatments are available to give concrete a fresher and more modern look.

Steps in Building a New Concrete Driveway

If you’re up to the challenge of building your concrete driveway, you can follow these steps.

Plan your driveway’s design.

In creating the design of your driveway, consider the number and size of the vehicles you have and whether you need space to turn or manoeuvre your vehicles. If you’re working on a large space, you might want to add a few enhancements, like greenery or a water feature.

Keep in mind that the size of your driveway affects the cost of the project as it will determine the number of materials you need.

Mobilise materials to the site.

After sorting out your design and budget, gather all the supplies, materials, and equipment you need to build.


Prep the area.

Start by removing existing material like grass, leaves, and trash. Once cleaned of debris, it is easier to for you to create the layout of the garden, firm up the base and lay down the concrete.

Install forms.

Drive metal or wooden pegs at the boundaries and connect them with strings. Doing this will let you see the layout of your driveway and guide you on where to pour the concrete.

Compact the base.

If the ground you’re working on is loose or sandy, a clay base will do. For loamy soil, firm it up with sand or gravel. You may consider adding weed control substances if necessary. After adding material, dampen the base with water to make soil compacting easier.

Install stabilisations sheets and grade pegs.

To strengthen the base, you can install stabilisation sheets. This can be a geotextile fabric that helps reduce materials from sinking. Grade pegs serve as a guide on how much concrete you should pour to achieve the correct height.

Pour concrete.

Lay down the concrete mix from the corner, then spread it evenly using a rake or shovel. If concrete seeps through the edges, remove it with an edging trowel. Keep in mind that the concrete needs to be at a height of at least four inches for it to withstand daily wear and tear.

Level the surface.

Use a trowel to create a flat, level finish. Edges can also be smoothened out with a bullnose to remove rough areas.

Install contraction joints.

As concrete dries, it expands and could crack. You can avoid this by using wood …

What Can Go Wrong with Soakwells?

A soakwell, also called a storm pit, drywell or soak hole, is an underground reservoir that catches water runoff and slowly disperses water to the surrounding soil. A soak well is an important part of a property because it prevents water build-up that may affect the structural integrity of buildings and other structures above or near them.


Whether you own a residential or commercial property, you must ensure that your soakwell system is properly maintained. Even if containing water runoff is not a problem in your area, keeping a well-managed soakwell can protect not only your property but also neighbouring properties should unexpected weather conditions happen.


What Can Go Wrong with Your Soakwell?


A faulty soakwell system can result in many problems. It can cause the surrounding soil to absorb too much rainwater quickly, and eventually result in sinking pavers, grass or concrete. Rainwater can also rise and dampen walls, floors and footing. If wooden structures are above the soakwell, the rising water could rot and weaken the wood.


You might deal with the following issues if the soakwell in your property is not efficiently managed.


A Soakwell deteriorates and collapses.

If the soakwell in your property is made from poor quality materials, it can collapse faster than expected. If the paving above the soakwell sinks or you see sand rising through, this could mean that the soakwell is damaged or has collapsed.


A soakwell is unable to control heavy runoff.

Besides using poor construction materials, another reason a soakwell could underperform is when it cannot retain the expected volume of water that enters it. To prevent this, you or your soakwell contractor must calculate the soakwell volume capacity based on the size of the catchment area. Upon calculating the volume capacity, you can either replace the existing soakwell or install additional soakwells.


Soakwell is filled with debris.


Sand, debris, or other sediments can enter the soakwell along with water. These materials can also penetrate if there are gaps in the soakwell’s lid. When there’s too much material inside the soakwell, they can block the holes in the soakwell’s walls, preventing water to seep out of it. This may lead to soakwell damage or collapse if left untreated. To remedy this, you can hire soakwell cleaning services to remove materials and clean the soakwell. You can also prevent materials from seeping inside the soakwell by installing a filter on the drain line or cleaning gutters and pipes regularly.

Avoid most of these problems with properly by having Dobson Excavation take care of the soakwell installation.…

Firebreaks in all areas Perth-Metro and Rural

Firebreaks in all areas Perth-Metro and Rural

Fire season is upon us again, notices are being mailed out from councils.

Your Legal requirements if you live on 1 acre or less for firebreaks, Cut all grass which has to be less than 25mm in height and maintained until 31st May, 2021. Trim all overhanging trees and bushes which hang over driveways, access ways and firebreaks to leave a 4 metre width clearance and a clear vertical axis. Or Install firebreaks that are inside all external boundaries, Install fire breaks surrounding all agricultural buildings, sheds etc. A minimum of 3 metres width no wider then 5 metres.

If you live on more than 1 acre for firebreaks

Keep grasses below 150mm or if used for grazing ensure rotation of grazed and un-grazed areas. Trim all trees and bushes which are over hanging driveways/access ways and firebreaks, and leave a 4 metre width clearance. Install firebreaks inside all external boundaries, and surrounding sheds etc with a minimum 3 metre width.

For dwellings Maintain 20 metres asset protection zones or as per your approved BAL/FMP assessment. Trim back all tress overhanging buildings.

Contact your local council for advise on firebreaks as some councils have different rules, the above is from Serpentine Council, or read your brochure you council supplies.

We at Dobson Excavations can assist with your firebreaks or fire prevention, with either our Brush cutter slasher, which can cut down to ground level small trees/bushes/scrubs/weeds etc, it can also trim trees that are over hanging driveways access way and firebreaks, plus it slashes grass. Check out our link for a demonstration www.dobsonexcavations.com.au/attachement/ or call Bruce on 0414755306.


Brush Cutter Slasher Attachment for Bobcat Hire-Serpentine-Keysbrook-Jarrahdale-Perth

Brush Cutter Slasher Attachment for Bobcat Hire-Serpentine-Keysbrook-Jarrahdale

Do you have either a bush block that requires clearing or a block of land with over growth of scrubs/bushes etc, required to be cleared so you can build you home/shed/Water Tanks/Driveways/Trenches.

Then Our Bobcat Case TR320 has a Brush Cutter/Slasher attachment, which handle this job, the Brush Cutter is a BRX318 produced by CAT,

The Overall Width -1911mm, Cutting Width-1829mm, Max Cutting Diameter 203mm, Weighs 1072Kg.


This Brush Cutter is used for clearing overgrowth such as scrubs/bushes/small trees/grass etc, it cuts down to ground level. It can even trim trees. Used as a slasher also for grass cutting instead of using a tractor.

The Brush cutter attached to the Bobcat can be used to clear land, Fire Prevention, House sites, Parks, Recreational areas, Council verges, Main Roads.

We also have a link to our web site which shows you the Brush Cutter Slasher in action, link below.


Contact Bruce 0414755306 or email us at dobson_excavations@live.com





Septic Tanks Supplied and Installed in Concrete from Perth-Lake Clifton-Myalup-Bunbury

Septic Tanks Supplied and Installed in Concrete from Perth-Lake Clifton-Myalup-Bunbury


Supply of concrete products and installation at Dobson Excavations, we not only excavate the hole for the septic tanks but we supply them also. We are your one stop earthmoving business, we cater to our customers a service, so customers do not have to hire different business to complete different jobs. At Dobson Excavations we can complete the job from start to finish.

If you check out our web page www.dobsonexcavations.com.au you will be able to view our work and machinery.

As for the installation of Septic Tanks in concrete, septic tanks are used for disposal of sewage and effluent, so concrete is less likely to break or spilt compare to plastic, yes plastic is cheaper, but do want to have to in the end waste more money years or months later to have to replace them if they spilt or cave in, at least with concrete you know they will most probably out last you.

Septic tanks are installed with either 2 leach drains or 2 sets of soak well tanks, These systems are called alternating systems as they have a diverter box which can change the flow of effluent allowing one half of the soak wells or one of the leach drains to be shut off at anytime. This allows the unused portion to dry out which rejuvenates the soils ability to receive effluent.

All the concrete products we supply are approved to Australian Standard AS/NZS 1546.

Contact Bruce on 0414755306


Farm Dam Construction and Dam Clean Outs Perth -Rural-Metro

Farm Dam Construction and Perth-Rural-Metro

Farm Dam Construction is not a case of digging a hole and waiting for it to fill with water. Many farm dams fail because they were not constructed or planned out correctly. Most farm dams are compacted earth structures built at depressions, gullies or hillsides. Farm dams should be planned and built with the same care you would apply to building a house.

Things to consider when planning a Farm Dam Construction

• Government regulations that apply to your Farm Dam Construction check with your local council for regulations.

• Size of your dam allowing for evaporation and Farm requirements.

• Where to build your Farm Dam: A Gully usually is a good place to site a dam because it reduces the amount of earthworks and the overall cost. However, not everyone has the advantage of a gully site on their property; many farm dams are built on hillsides.
Two important considerations, the catchment yield and the soil type at the site.

• Preparing your site: Before building starts, the area to be covered by the embankment, spillway and excavation should be stripped of all topsoil, roots and vegetation (including trees and stumps). Store the topsoil for use in the completion of the embankment and spillway.

• Building your dam :The successful completion of an earth dam relies heavily on achieving a well-compacted embankment.
Apart from soil compaction, other major construction considerations include: • the cut-off trench • exposed rock • spillways • clay cores • embankment batters • freeboard • settlement of the embankment • crest width • topsoil use.

• Maintaining your dam. To allow the storage to fulfil its function it is important to carry out regular maintenance. It also helps to observe the following.
Ensure topsoil cover of at least 150 mm.
Establish a grass cover on the embankment and spillway as soon as possible. A grass that mats, such as kikuyu, is preferable to a grass that tufts.
Do not let trees or shrubs grow on the embankment, spillway or spillway outlet slope. Roots might disturb the compacted soil and provide a seepage path for water, while trees or shrubs in the spillway area will restrict the flow of flood water.
It is worthwhile to choose an earthmoving contractor who has experience and a good work record. Not every contractor has the experience or the ability to build a dam.  At Dobson Excavations we have this experience. Contact Bruce on 0414755306 for a site visit and advise on your Farm Dam Construction. 

www.dobsonexcavations@live.com      #dobsonexcavations




Installing Soak Well Tanks for water or rain diversion Perth-Bunbury-Australind-Myalup-Preston Beach

Installing Soak Well Tanks for Water or Rain Diversion Perth-Bunbury-Australind-Myalup-Preston Beach

Soak well Tanks are an underground structure which allows rain water to drain away.

If rain water is not diverted away or runs off into a soak well tanks, than the rain water can cause your property and sometimes affect neighboring properties.

Which can cause Erosion of house pads, footings, Rising dam to walls, Floor and Foundation damage.

Soak well tanks work by collecting rainwater diverted by pipes attached to gutters, holes in the tanks allow seepage into the soil, they are installed underground.

They come in various sizes and traffic able lids are available if vehicles need to travel over them.

Concrete Soak well tanks will last longer and not collapse with weight over time.

At Dobson Excavations we supply concrete soak well tanks and install them.

Contact Bruce for a free quote today 0414755306

Mini Excavator for Tight Access or Limited Space for Hire

Mini Excavator for Tight Access or Limited Space for Hire

Is Tight Access a problem with your site? Or Limited Space where a machine can not turn or move around?

With our Mini Excavator its width is 98cm just under a meter, combined with our mini dump truck which is 790mm, we can assess just about anywhere, through garages, carports, side access.

We can access your yard with our Mini Excavator to install Leach drains, septic or soak well tanks, and Shed Pads, sand pad extensions, trenches, lawn removal, pool holes, rubbish removal etc.

If materials are required we supply sand and soil,than our Mini Excavator assist,  if materials are needed to be removed than our Mini Excavator and dump truck can move it out of your tight access or limited space.

Our Mini Excavator is a 1.7 Ton Hitachi ZX17U-S, our mini dump truck is a Wacker Nelson DT08.

Contact Bruce on 0414755306 for a site visit and a free quote.

Also visit www.dobsonexcavations.com.au to view all our machinery.


Soak Well Concrete Tank Supplied and Installed in all Area of Perth Metro/Rural

Soak Well Concrete Tank Supplied and Installed In all Areas of Perth Metro/Rural

Soak Well Concrete Tank supplied to your site and installed.

Soak Wells are used for drainage of water, where for example rain flows from gutters down pipes into soak wells, then the water seeps out the holes of the soak well concrete tank into the ground.

Concrete Soak Wells will last for many more years than plastic, as a soak well concrete tank can have a traffic-able lid install so you can drive over them.

Concrete Soak Wells come in different sizes starting from 900mm, 1200mm, 1500mm, and 1800mm as per the chart below


600 x 900   600 x 600                                                                                           Wall Thickness 60mm

900 x 1200       900 x 900         900 x 600                                                         Wall Thickness  60mm

1200 x  1500     1200 x 1200     1200 x 900      1200 x 600                             Wall Thickness 75mm

1500 x 1500     1500 x 1200       1500 x 900     1500 x 900    1500 x 600     Wall Thickness 75mm

1800 x 1800     1800 x 1500      1800 x 1200    1800 x 900   1800 x 600     Wall Thickness 90mm


CONTACT BRUCE ON 0414755306 OR email dobson_excavations@live.com