Mould on Lace Curtains and Window Frames: What Should You Clean, Wash or Replace?

Check the fabric care label and the damp window behind it.

Look behind the curtain first

Lace and net curtains can hide a damp sill or a patch of growth at the bottom of the frame. Take them aside and check the glass, frame, surrounding wall and the side of the fabric that faces the window.

Photograph mould and water damage before cleaning. A damp window area may involve condensation, water entry or both. Cleaning the fabric will not fix a leak around the frame.

Decide whether the fabric can be washed

Read the curtain’s care label before choosing a product or wash cycle. Delicate lace, aged fabric, linings and decorative finishes may need different treatment. Do not assume that a white curtain can tolerate chlorine bleach or machine washing.

For washable curtains, remove hooks and other fittings as instructed and avoid overcrowding the machine. Follow the permitted temperature and drying method. If the material is fragile, heavily affected or cannot be cleaned adequately, ask a curtain cleaner whether cleaning or replacement is appropriate.

A curtain whitening option

White lace curtains can look tired long before they need replacing. Dr. Beckmann Curtain Whitener is one option for suitable washable white curtains, including nets, sheers, voiles and lace. We found it at Mitre 10.

Although Dr. Beckmann Curtain Whitener does not claim to eliminate mould, we have found it very successful at removing visible mould stains and bringing fresh life back to white lace curtains.

We usually get a good result using a gentle cycle, provided the curtain care label permits machine washing and that cycle meets the product instructions. Removing a stain does not confirm that all mould has been eliminated, so check the window area for ongoing dampness too.

Follow the current packet instructions alongside the curtain care label for dosage, wash temperature and drying. Use the whitener with detergent as directed, and do not apply the powder directly to fabric. Observe the label’s eye-safety precautions and keep the product away from children.

When should you consider replacement?

If fabric is brittle, tearing, heavily affected or cannot be cleaned using a suitable method, ask a curtain-cleaning specialist whether it can be salvaged. Replacement may be appropriate when cleaning would damage it or cannot adequately address its condition.

A remaining stain alone does not prove that mould is still growing. Equally, a whiter curtain does not prove that all mould has been eliminated. Check the fabric condition and the dampness around the window before deciding.

In a rental, discuss replacement of landlord-provided curtains with the property manager before disposing of them. Record the condition and agree the next step.

Drying matters after washing

The product directions allow hanging curtains damp after a brief spin. If the fabric care instructions permit that method, provide enough airflow for them to dry completely and keep them away from wet glass or a damp wall. Do not fold or store them damp.

If the room cannot provide those conditions, use another drying method permitted by the fabric care label. A bright-looking curtain should not go straight back against the same wet surface.

Clean the window and check for repairs

Wipe condensation from the glass and clean small accessible patches on sound washable frames with a suitable product used as directed. Dry the surfaces and avoid soaking timber or damaging seals.

Look for swelling, soft timber, peeling finishes or water appearing after rain. Keep designed drainage openings clear according to the manufacturer’s instructions. Report repair concerns to the property manager rather than sealing over them.

If mould returns on the curtain or surrounding wall, contact Steve at NZ Healthy Homes about investigating the property conditions. Rewashing should not become the only response to recurring dampness.

Washing the curtain will not fix the damp window behind it.

Source information checked on 14 October 2026. Product performance observations are practical experience, not laboratory evidence of mould elimination.