Building contracts

We act for builders, developers, sub-contractors, engineers and architects as well as owners of residential and commercial property on all building contract and payment disputes.  We advise on all Building and Construction contracts including Australian Standards and HIA contracts.

We also handle disputes over building contract price increases for residential and commercial matters.

Lump Sum Home Building Contracts – Can the price be increased?

Since the introduction of the Federal HomeBuilder and WA Building Bonus grants, there have been issues relating to delays in the construction process and claimed increases in builders’ costs, which we have seen builders look to pass on to owners under their building contracts.

Whilst the widely used Lump Sum Building Contract specifies a price for home construction, there are clauses that allow builders to increase the so-called ‘lump sum’ price in specific circumstances.

Owners are often unaware of these price increase clauses, their rights, and the process to dispute a price increase notice from the builder. If owners want legal advice on disputing a price increase notice they should seek that advice urgently, as there are strict time limits for the dispute process.

See Building and Construction for more information.  Department of Mines, Industry Regulation and Safety have also issued a helpful guide - A Guide on price increases to home building work contracts.

Our practice is located outside of the Perth CBD and because of this our hourly rates and fixed prices for commercial work and for litigation are 20% lower than the standard rates charged by most Perth law firms.  Our rates are extremely competitive compared to the rates charged by other commercial law firms. 

We advise clients before they sign building contracts on important terms and help clients having problems with their builders.


For 25 years we have provided advice on all building contracts and sub-contracts and on building contract and sub-contracts disputes including payment claims, disputes over variations, Construction Contract Act claims, disputes over delays in building works and claims over defective works and appearances in the Supreme Court, the District Court and the Magistrates Court.

Our clients include builders and their customers, developers, sub-contractors and owners of both residential and commercial property needing advice and representation on all building contract and payment disputes.

Building Contract Disputes

We provide advice on all building contracts and on building contract disputes including payment claims, disputes over variations and Construction Contract Acts claims.

Aherns Lawyers are experienced at providing legal advice and services in relation to all building contract disputes, including:

* claims by builders failing to complete projects:

    a. within budget without valid justifications provided for by the contract; or

    b. within the time period allocated by the contract subject to valid extensions of time provided for by the contract.

* claims by builders requiring progress payments or refusing to provide access to the site without having reached the corresponding milestone;

* claims or disputes as to the quality of workmanship and the party who should be liable for such defects;

* claims for damages as a result of breaches of a building contract.

See also Building and Construction for more information on our success in handling construction cases