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.