For anyone living with aspergillosis, ABPA, bronchiectasis or asthma, mould exposure can trigger symptoms or flares. Recently, several patients have reported that rough-cut timber is arriving mouldy from DIY suppliers, sawmills, or timber merchants.

Here’s why this happens — and what suppliers should be doing to prevent it.


Why rough-cut wood gets mouldy (especially in the UK)

Mould grows on timber whenever three conditions are present:

  1. Moisture

  2. Poor airflow

  3. Warm or humid air

Rough-cut timber is especially vulnerable because:

  • its uneven surface holds moisture,

  • it is often stacked tightly,

  • it may not be dried properly,

  • and UK weather (rain + high humidity) encourages mould.

Many suppliers wrap wood in plastic, which traps condensation during transport. This can create a humid “greenhouse” around the timber — perfect for mould growth in only 24–48 hours.


What UK suppliers should be doing (even for low-cost timber)

These are standard industry practices in UK timber yards and sawmills. None of them require wood to be kiln-dried (which is more expensive).

✔ 1. Air-dry properly (“sticker stacking”)

Boards must be stacked with spacers (“stickers”) between them so air can circulate.
No airflow = mould.

✔ 2. Store under cover, not outside in the rain

A simple open-sided shelter is enough.
Rain-soaked timber nearly always grows mould in transit.

✔ 3. Use breathable wrapping — NOT plastic sheeting

Plastic traps moisture.
Breathable paper wrap or perforated cover prevents condensation build-up.

✔ 4. Apply anti-fungal dip (borate)

Most UK sawmills use anti-mould dips to prevent blue-stain and mould during storage.
This costs pennies per board.

✔ 5. Moisture-test before delivery

A good supplier will check wood is below 20–22% moisture before dispatch.
Wet wood + UK weather = guaranteed mould.


Kiln drying is not essential

Kiln-dried timber is more expensive because it uses energy, equipment, and time to force-dry the wood.

But you do not need kiln-dried timber to avoid mould.

You simply need a supplier who:

  • stores the timber properly,

  • allows airflow,

  • avoids plastic,

  • and checks moisture before delivery.

If rough-cut wood is arriving mouldy, it usually means these steps were not followed.


What you can do to protect yourself (aspergillosis patients)

If you receive wood that:

  • smells musty,

  • has surface mould,

  • or shows green/black spots,

…it is best not to bring it indoors until cleaned.

✔ Immediately unwrap outdoors

Plastic wrapping traps mould spores.

✔ Keep well away from ventilation intakes, windows, or living areas

This avoids airborne spores entering the home.

✔ If mould is visible — return it

You have the right to reject mouldy timber.

✔ If keeping it, clean outdoors with PPE

Use:

  • gloves

  • FFP3 mask

  • borax solution (borax + hot water)
    to remove early surface mould.

Never sand mould indoors — sanding releases spores.


Simple Diagram: Correct Way to Store Wood to Prevent Mould

Correct storage includes:

  • boards stacked with spacers between them (“sticker stacked”),

  • raised on bearers above the ground,

  • stored under a roof with airflow on all sides,

  • NEVER wrapped in sealed plastic,

  • ends exposed to allow moisture to escape.

This method is cheap, simple, and prevents mould without needing expensive kiln drying.


Summary for Aspergillosis Patients

Rough-cut wood should not arrive mouldy.
Mould growth usually means it was:

  • stacked badly,

  • stored wet,

  • wrapped in plastic,

  • or shipped before drying.

For people with aspergillosis, ABPA, bronchiectasis or severe asthma, mould spores can trigger symptoms — so it’s completely reasonable to:

  • refuse mouldy timber,

  • request proper handling,

  • or ask the supplier to follow UK best practice.

Path: Start » Conditions » ABPA » 🌲 Why Rough-Cut Wood Arrives Mouldy — and How to Reduce the Risk (Important for Aspergillosis Patients)

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