Backfilling Fire Door Frames Explained

There has been a high level of confusion in the marketplace regarding backfilling fire door frames. We take a look at the ins and outs of the subject.

A Little Background

In 2005, there were changes made to Australian Building Code Standards (AS1530.4) that required measurement of temperature rise on the fire door frame and the fire door itself, when subjected to the standard fire door test. Consequently, the frame needed to be insulated to ensure it met the temperature rise requirements.

Frames for fire doors were originally backfilled to insulate them and stop them from deforming and deflecting under the standard fire door test’s stress. However, accumulated test knowledge and test results had proven that backfilling was not always necessary, as the wall’s performance influences the frame’s performance. This ongoing research and development, the push from the construction industry for reduced building costs, and no requirement for measurement of the door frame’s temperature rise led to hollow or unfilled frames being acceptable.

It is important to note that this particular requirement was not present in earlier standards, and that is why fire door frames could previously be installed without any backfilling. AS1530.4-2005 is the referenced standard in the current BCA. However, the BCA allows for prior test results to be used (please refer to BCA “GENERAL PROVISIONS” “SPECIFICATION A1.3 DOCUMENTS ADOPTED BY REFERENCE”; there is a self-explanatory note regarding testing requirements and the acceptance of test results before 2005).

The Building Code of Australia

The BCA is a living document that evolves continually. For this reason, building design and compliance requirements are locked into a specific version (i.e. issue date) of the BCA. The process of planning and designing a building will take several years. At some point, the design is “locked-in” to a specific set of standards, and this is what applies to the BA/DA and under what specification the building is constructed to. If the building were finalised in 2007 and subsequently approved for construction by the relevant authorities, it would be designed and built to those standards (even though it may not be completed until a later date).

backfilling fire door frames

So, unless the approval/certifying authorities have specified a particular requirement to meet the latest standards, then the standards of the day prevail. As a result, many of the buildings we work with today will contain fire-rated and non-rated door frames. It is important to understand that if this logic did not apply, a building would never get completed as the ongoing change in standards (not just fire doors) would mean nothing would ever comply.

FSE Special Purpose Doors recommends that all fire door frames be backfilled to be safe and avoid potential certification problems. This ensures there is no margin for error and that there will be no future costly rectification works (it is impossible to backfill partition wall frames post-installation). Other factors to be considered regarding backfilling fire door frames include acoustic performance, the door size and long term durability.

Backfilling Methods

Several backfilling custom fire door frames include E-Core® strips, non-shrink Mortar/Cement/Grout; Fire Rated Plasterboard strips Casting Plaster. When a fire door frame is built into a plasterboard wall, it should be backfilled with fire-rated plasterboard strips before installing into the wall. Unfortunately, it is not possible to fill frames in plaster walls post-installation.

In all cases, it is imperative that the backfilling medium is tightly packed and all available airspace is filled. Furthermore, the finished backfilled frame must be tightly sealed against the surrounding opening fitted to using an approved fire rated sealant.

FSE Special Purpose Doors uses and recommends E-Core® fire doors. There are many approvals where backfilling fire door frames is mandatory (as per the tested prototype), so it is critical to establish this before construction commences to avoid issues when trying to tag and certify the job at its conclusion.

Get in touch

At FSE Special Purpose Doors, we specialise in several different fire doors, including hinged fire doors, sliding fire doors and double action fire doors.

For any enquiries or assistance with the backfilling fire door frames or non-rated frames, please contact FSE Special Purpose Doors at [email protected] or call 1300 4 DOORS.

While you’re here, learn some more about fire doors and fire safety.

How to ensure your building is fire-safe

Fire-resistant rating: Fire doors

Installing fire doors: The requirements



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