Ply facings on fire doors

The preparation of the door, prior to and between coats, is a fundamental and integral part of the painter’s scope; and this is of particular importance for treated plywood facings on higher FRL fire-rated doors.

The treatment applied (to ensure the higher levels of fire-resistance) is prone to leaching through to the surface of the ply – this is not to be mistaken as any sort of defect; but rather is consequential of the treatment itself and the normal reaction to the environment (open air), variable to moisture levels, in the air.

Care must be taken to ensure this residue is not simply ignored and painted over, as it will lead to paint adherence failure, and continued leaching.

The correct method of care and preparation is as follows;

• Remove excess residue with damp cloth / sponge
• Wait for door face to dry back; and apply prime coats, absent of too much delay
• Upon adequate drying, sand the prime-coat.
• Apply subsequent top-coats of an oil-based paint finish, to required level of painting (consistent with both the Australian Standards for door finishing, and also the manufacturers recommendations), which for treated ply is 4 coats (after priming); but importantly, sand between coats, including prior to final (top) coat application.

Note: The use of light-reflective paint colors (per AS1909) are important, particularly those exposed to sunlight, to prevent door distortion, and therefore urged in all instances

As always, and regardless of whether treated or un-treated door facings; where high levels of exposure exist (eg: western exposure; nil cover-over, etc) it is always recommended to look at additional options such as metal cladding to ensure warranty and continued door performance.