How to avoid coating failures in winter: Teknos’ expert guide

As temperatures drop, factory-finished joinery faces one of its biggest annual challenges: winter. Low temperatures and high humidity make coating application and curing more difficult and can also affect timber stability.

To help, Teknos has put together a series of simple, practical steps you can follow to minimise cold-weather disruption and avoid expensive rework.

The hidden risks of winter production

Cold weather introduces several risks:

• Paint can become cold or even freeze during storage

• Joinery may be delivered before coatings are fully cured

• High humidity can contribute to excessive dimensional movement in standard species, opening joints to moisture and causing door sets and windows to ‘stick' or operate poorly

Rectifying these issues on site adds cost and frustration for everyone involved. However, simple steps taken during distribution, storage, joinery manufacture and on-site installation can greatly reduce – and often prevent – the problems associated with winter conditions.

Understanding how paint cures

Modern water-based coatings dry and cure in two stages:

1. Coalescence– Water and solvent evaporate from the wet film and the coating begins to crosslink. The surface may appear dry at this stage, but it may still be moisture-sensitive and certain components (such as stain blockers) may not yet be fully effective. Lower temperatures significantly slow this stage.

2. Chemical curing – The coating then chemically crosslinks, improving toughness and adhesion. In warm summer conditions or well-controlled factory environments, this may occur within a few days. In cold, damp conditions, curing slows dramatically and may stop completely near freezing.

If joinery is exposed to the elements before curing is complete, it remains vulnerable until warmer, drier conditions allow the process to resume.

Six practical steps for the factory

1. Keep paint in a heated store before use and never leave cans on a cold concrete floor.

2. Follow the recommended film thickness. Over-application wastes product and slows drying.

3. Maintain factory drying conditions at a minimum of 15-22°C in the spray booth and drying area using background heating or ducted, filtered warm air. Use simple fans to maintain air circulation.

4. Leave heating and circulation fans on overnight (timed). Little drying occurs in cool, still air.

5. Avoid blasting hot air directly at joinery. This accelerates surface drying but traps moisture in the film and interferes with coalescence. Contact Teknos for advice on forced drying.

6. Delay wrapping finished joinery for as long as possible. Wrapping or storing items in an unheated despatch area can slow or stop moisture release, preventing full coalescence and curing.

   
   

Don’t forget the timber itself

The moisture content of exterior joinery varies significantly throughout the year and is largely independent of any treatments or coatings. Dimensional change depends on species and grade, but standard timbers typically move by about 1% for every 3% change in moisture content.

In winter, joinery often leaves factories at around 10% moisture content – sometimes lower when laminated sections are used – and can quickly condition to 18-20% on site. This 3-4% dimensional change can open joints and seals, allowing moisture to penetrate exposed end grain and rebates.

Six practical steps on site

1. Remove airtight packaging before storage to allow free ventilation of joinery items.

2. Store joinery off the ground on suitable bearers and cover with a permeable sheet for contamination protection.

3. Ensure storage areas are well ventilated and avoid extreme temperatures. Don't store items in metal box containers, which may suffer from condensation and extreme heat. Moisture can also collect in protective wrapping, saturating components.

4. If joinery is installed before internal wet processes are complete, use gentle heating, good ventilation and dehumidifiers to reduce the risk of blistering and delamination during building dry-out.

5. Remove plaster and building material contamination immediately using a detergent solution, then rinse with clean water.

6. Ensure all on-site assembly or modifications are fully protected, especially cill joints, glazing beads and glazing systems. Any exposed end grain must be sealed with two generous brush coats of Teknoseal 4000 before recreating the full paint system.

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Final word

Winter doesn’t have to mean coating problems. By monitoring temperature, airflow and moisture levels, joinery manufacturers can maintain a high-quality finish and avoid costly rework.

For more technical advice or guidance, visit the Teknos Technical Library at www.teknos.co.uk or email sales@teknos.co.uk.