ENGINEERING CERTAINTY. DELIVERED.
The ground beneath a structure needs more than the right soil—it needs to be properly placed and compacted.
Engineering On Demand provides Compaction Testing for residential and construction projects across Perth and Western Australia, helping builders, homeowners, engineers and contractors verify that prepared ground and fill have achieved the required compaction.
Our services include Soil Compaction Testing, site testing, earthworks verification and preparation of a Compaction Report or Compaction Certificate within the applicable scope.
Whether you’re preparing a new house pad, extension, patio, pool or other structure, we can provide the testing required to establish whether the tested earthworks satisfy the nominated compaction criteria.
Placing fill doesn’t automatically mean the ground is ready to support construction.
Fill needs to be suitable for its intended purpose, placed appropriately and compacted to the required standard. Poorly controlled earthworks can contribute to settlement and movement after construction.
Soil Compaction Testing provides evidence of the condition achieved at the locations and depths tested.
Engineering On Demand can coordinate testing of prepared building pads and other earthworks so the results can be reviewed before subsequent construction proceeds.
This gives the project team evidence rather than relying simply on how firm the finished surface appears.
Foundations transfer building loads into the material below.
Where a building is founded over placed fill, the quality of those earthworks can therefore directly affect the performance of the structure.
Compaction reduces voids within the placed material and helps establish the density required by the relevant earthworks specification.
Testing provides a means of checking the work against a nominated criterion.
WA Government construction specifications, for example, require fill to be systematically placed and compacted and reference AS 3798 for earthworks requirements and AS 1289 methods for compaction-control testing.
Before testing, the relevant earthworks need to have been placed and compacted.
The fill material, layer thickness, moisture conditions and compaction method can all influence the result.
Testing should therefore be coordinated with the earthworks process rather than treated as something completely separate from it.
Testing is undertaken at selected locations within the relevant earthworks area using an appropriate test method.
The method depends on the material, project requirements and nominated testing criteria.
The purpose is to obtain measurable evidence of the compaction achieved rather than relying on visual assessment.
The results are assessed against the specified compaction criteria applicable to the project.
A test result isn’t simply a generic “pass” because the required result can depend on the specification, material and intended use of the earthworks.
This is why the required criteria should be understood before interpreting the result.
The results can then be documented in a Site Compaction Report identifying the relevant testing and outcomes.
The report provides the builder, engineer or other project professional with evidence relating to the tested earthworks.
AS 3798 – Guidelines on earthworks for commercial and residential developments is a key Australian Standard used for earthworks control and testing.
It addresses matters including fill materials, placement, compaction, inspection and testing.
WA Government construction specifications reference AS 3798 for earthworks, including compaction and testing requirements. One current specification requires Level 2 sampling and testing to AS 3798 and uses its Table 8.1 for testing frequency.
The applicable testing requirements still depend on the individual project and its specification.
This means there isn’t one universal compaction percentage or number of tests that should be advertised as correct for every EOD project.
That distinction makes the page technically much safer than saying—as the existing page effectively does—that testing simply determines whether soil meets “the required density standards.”
The AS 1289 series contains methods used for testing soils for engineering purposes.
WA Government specifications reference methods including AS 1289.5.4.1 and AS 1289.5.7.1 for compaction-control testing.
The appropriate method depends on the project, soil and testing requirements.
Engineering On Demand can coordinate the testing appropriate to the required scope rather than presenting one field-test method as suitable for every site.
Earthworks Testing is most effective when incorporated into the earthworks process rather than left until everything has been completed.
Fill is commonly constructed progressively in layers. Appropriate placement, moisture conditioning and compaction of those layers can influence the performance of the finished earthworks.
WA Government earthworks specifications require systematic layer placement and compaction and reference test frequencies under AS 3798 for applicable works.
For projects requiring controlled earthworks, testing at the appropriate stages provides better information than attempting to reconstruct the history of the fill after construction.
Many Perth residential projects involve predominantly sandy foundation conditions.
Sand can often be effectively compacted using appropriate equipment and moisture conditions, but surface appearance alone does not verify the density achieved.
Testing provides objective information about the prepared ground at the test locations.
For residential projects, this can be particularly relevant where fill has been imported, ground levels have been changed or a new building pad has been prepared.
Clay and other cohesive soils behave differently from clean sand during earthworks.
Moisture content can have a significant influence on how effectively these materials compact.
The relationship between moisture and achievable dry density is therefore an important consideration when evaluating cohesive fill.
Where clay or unusual materials are involved, the appropriate testing methodology and earthworks requirements should be established for the particular project rather than applying assumptions derived from sandy Perth sites.
A new house pad can involve excavation, imported fill, redistribution of existing material and mechanical compaction.
Before footing or slab construction proceeds, the builder or engineer may require evidence that the relevant earthworks satisfy the project’s compaction requirements.
Engineering On Demand provides Compaction Testing for new residential building pads and can issue the applicable testing documentation following assessment of the results.
Extensions frequently require new foundations beside an existing building.
Where ground levels have been altered or fill has been placed beneath the proposed extension, compaction verification may be required before the new footing system is constructed.
Engineering On Demand can coordinate Soil Compaction Testing together with the subsequent structural engineering required for the extension.
Transportable and conventionally constructed granny flats both rely on appropriately prepared foundations.
Where a new pad or structural fill is required, testing can provide evidence about the compacted earthworks before footings, slabs or other foundation systems are installed.
Engineering On Demand can coordinate the Site Compaction Report with the broader engineering requirements for the granny-flat project.
Compaction testing isn’t limited to houses.
Patios, sheds, garages, workshops and other structures can also be constructed over areas where fill has been placed or existing ground levels altered.
The extent of investigation or testing required depends on the structure and site conditions.
Backfill behind and around retaining structures requires particular consideration.
The fill needs to satisfy the project requirements without compaction operations imposing inappropriate loads on the wall.
WA Government specifications specifically address placing fill adjacent to structures and caution that compaction operations must not damage the works.
Where retaining walls form part of the project, the structural and earthworks requirements should therefore be considered together.
Service trenches disturb previously established ground and subsequently need to be backfilled.
Where required by the project specification, the backfill should be placed and compacted progressively rather than simply filling the trench in one operation.
For example, current WA Government specifications require service-trench fill to be compacted in controlled layers and specify compaction testing requirements.
Compaction testing can therefore also apply to trench reinstatement and other localised earthworks—not only large building pads.
Imported fill introduces two separate questions:
Is the material suitable?
and
Has it been properly placed and compacted?
These should not be confused.
A compaction result provides information about the density achieved at the tested location; it does not automatically establish every property of the imported material.
WA Government earthworks specifications separately require evidence for imported fill and compaction-control test results, illustrating this distinction.
Where material suitability needs to be established, additional testing or geotechnical assessment may be required.
A failed test doesn’t necessarily mean the entire site needs to be excavated and replaced.
The appropriate response depends on the reason for the result.
The material may require additional compaction, moisture adjustment, reworking or another remedial approach appropriate to the site.
After remedial earthworks are completed, the affected area can be retested to determine whether the required result has been achieved.
The important point is to resolve the issue before construction conceals the earthworks or loads are applied to them.
A Compaction Report provides documented evidence of the results obtained during field testing.
Rather than relying on assumptions about how the earthworks were completed, the project team has measurable information about the tested ground.
Where the results satisfy the nominated requirements, the documentation can support progression to the next stage of construction.
Distance shouldn’t mean building without the right foundation information.
Engineering On Demand provides Regional Site Classification services for residential projects throughout Western Australia, including Site Classification WA, Regional Site Classification Reports, site investigation and additional Geotechnical Assessment WA where required.
Start with an instant regional estimate or speak with our team about your project.
Compaction Testing measures characteristics of compacted soil or fill so the result can be assessed against the specified earthworks criteria. It provides objective evidence about the tested ground rather than relying on visual assessment.
A Site Compaction Report documents the compaction testing undertaken and the results obtained within the agreed scope. It can be provided to the relevant builder, engineer or project professional where required.
The term Compaction Certificate is commonly used for documentation confirming compaction testing and its outcome. The exact documentation and certification that can appropriately be issued depends on the testing scope, results and project requirements.
No. A Site Classification Report establishes foundation/site conditions for residential footing design. Compaction testing checks the compaction achieved in prepared ground or placed fill. Some projects require both.
AS 3798 is widely used for earthworks on commercial and residential developments, while methods from the AS 1289 series are used for soil testing. Current WA Government specifications reference both standards for earthworks and compaction-control testing.
There isn’t one percentage that should be applied to every project. The required criterion depends on the project specification, material, location and intended use of the earthworks. Testing needs to be assessed against the requirement applicable to that particular project.
Yes. New residential building pads are a key application for Soil Compaction Testing, particularly where fill has been placed or the site has undergone earthworks.
Yes. Compaction testing can be undertaken on sandy earthworks using the appropriate test methodology and project criteria.
Yes, although cohesive soils require different consideration, particularly in relation to moisture and density.
The affected earthworks may need additional compaction, moisture conditioning, reworking or other remediation depending on the cause. Retesting can then establish whether the required result has subsequently been achieved.
Potentially. The appropriate testing scope depends on accessibility and what needs to be verified. A current test cannot automatically certify every historical layer or area of fill that is no longer accessible.
That depends on the site, foundation system, earthworks and project requirements. Where compaction verification has been specified, it should generally be resolved before subsequent construction prevents the relevant earthworks from being appropriately tested.
Not automatically. The report relates to the testing undertaken and its defined scope. Test locations, frequency and the applicable earthworks specification determine what conclusions can appropriately be drawn.