Facts About Bowing of Doors

Timber and MDF doors generally warp or bow over time, resulting in gaps between the door and the frame, which can compromise energy efficiency, security and functionality. Most door manufacturers will not accept responsibility for bowing of doors.

• AS2688 does allow for bowing of doors.
• Up to 2150mm high, allows for 4mm of bowing.
• Up to 2400mm high, allows for 6mm of bowing.

The main sources of bowing doors are:

Storage of doors

Warping and bowing occurs often after doors have been delivered to site. It is usually due to improper storage or adverse moisture conditions before and after hanging, not poor manufacturing. When doors are delivered to site it is essential to store them correctly – immediately. Doors should be stored flat on a level surface, with equal support along their entire length. Do not store vertically or lean against walls as this can cause bowing.

Use spacers between each door to allow air circulation, running across the width of the doors. Store doors in a dry, well-ventilated area away from moisture and direct sunlight. 

Changes in moisture content due to unsealed doors

Doors should be sealed top and bottom as soon as delivered onsite

Immediately after fitting, and prior to hanging, the entire door, including the top and bottom edges, must be sealed as per requirements stated in AS2311:2017 and AS2688. Semi-gloss or satin finishes are recommended for all doors to reduce show-through.

Uneven loading

Bowing can also occur when there is uneven loading on the doors surface. It is critical that doors do not have one sided cladding or other equipment mounted to the door that may induce uneven loading on each side of the door.

After the door is hung

Maintaining a consistent temperature and humidity level in your home or building can help reduce bowing, as can ensuring proper ventilation and avoiding direct exposure to sunlight or heat sources.

Other tips to minimise warping or bowing of doors

• Ensure proper installation with appropriate clearance so the door doesn't get damaged when opening/closing.

• Install a cover above exterior doors to shield them from exposure to rain and the harsh Australian sun.

• Inspect doors regularly and address any issues promptly before warping worsens.

• Refinish the door yearly to maintain the protective coating.

If your door has already bowed, try adjusting the hinges or strike plate to realign the door. For more severe cases, you may need to plane the door or replace it.