National Hickman

Getting the Best from National Hickman Internal Doorkits on UK Building sites

• Keep the doors wrapped until in the plot where they’ll be hung. Stack flat off the floor until fitted.
• NEVER store Doorkits in un-ventilated containers
• Ensure plots are well ventilated at all times, particularly at night.
• After hanging, wedge doors half open, keeping conditions equally balanced (on both sides of the door)
• Keep plots well ventilated: open all window vents, set upstairs window sashes on ‘night vent’ position.
• Never use gas-fired heaters to dry out newly built houses; they give off water vapor and carbon dioxide ( CO2)
• Turn central heating on to constant, it should run all night at a low temperature, (max 15 C),  avoiding warm conditions in daytime followed by cold at night.
• Leave doors and windows wide open during the day wherever practical.
• Try to maintain air-movement throughout the house. In well ventilated plots, wind pressure will usually create movement.

The Reasoning:

All air contains moisture. Wood (and wood-fibre products) swell and shrink in proportion to the magnitude of change in its moisture content. Wood absorbs moisture from surrounding air.

The warmer the air, the greater the amount of moisture it can hold. Outside, water dries on a hot day because the air can absorb it.

Warm air is generally “wet” air. In a confined space (without ventilation), the capacity of air to hold moisture is limited. If a room or house full of warm “wet” air cools, the air can quickly no longer hold the moisture and condensation forms. These are Killer Conditions for wood based products.

Good ventilation prevents the build up of warm moist air. Conversely cold air from outside is usually “dry” air (depending on just how cold it is), even if it is raining outside.

Doors are manufactured at a moisture content that is normal for normal internal domestic use. If they are allowed to increase in moisture content the wood fibres will expand and the door skin will try to expand. Because it is constrained by its stiles and rails the door will not grow significantly itself but the skin will. Most door skins will absorb moisture to a point, but beyond certain levels, the skin will start to distort. In severe cases irreversible damage is done. More information on our doors can be found on the Jeld-Wen or Premdor websites.  You can also download this information in a more printable format here.