SAVE up to £195 per year on your energy bills by installing New Windows!
Answer these simple questions and we will find you the BEST prices.

What quotes do you need?

Mentioned in
The Guardian logoHarvard University logoIndependent logoForbes logo
Last updated: 31 August 2023

Black Mould on Windows: A Guide to Removal & Prevention

black mould on windows

Black mould on windows around your home is the last thing you want to see. It can not only damage your windows but can cause some serious health problems too.

Find out why it’s appeared, what you can do to remove it and how you can prevent it from ever making another appearance.

If your windows are especially old then they may be prone to letting mould spread in your home. Therefore, it may be time to replace your windows. To help you with this, GreenMatch can offer you up to 4 exclusive quotes from some of the best installers in your local area.

Rather than spending much time and effort finding installers by yourself, use GreenMatch’s free, no obligation quotes service. Get started today by clicking the button below.

Get your best deal
Quickly compare 4 FREE quotes
  • Quotes from local engineers
  • Payment by finance available
  • Save up to £170 per year

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon
Call us to get quotes
We will get you the best deal

Black mould on windows – why does it happen?

Any kind of mould is bad for the overall health of anyone living with it, but black mould is especially concerning. This type of mould is known as ‘Stachybotrys Chartarum’ and is known to form where there are excessive amounts of moisture in the air.

Black mould is known to produce a damp smell and can spread across paint, wallpaper and plaster, with the potential to cause serious problems with respiratory health.

It’s important that you don’t ignore even the slightest sign of black mould around your windows, or anywhere else in the home for that matter.

Some common causes of black mould in households are:

  • Damaged roof or window frames allowing rain in
  • Inefficient heating system
  • Leaking pipes
  • Taps, baths and showers
  • Rising damp.

Is black mould dangerous?

Mould can be very harmful to your physical and mental health, particularly if you already suffer from asthma, eczema or respiratory infections.

Mould spored release toxins, known as mycotoxins, which when breathed in can cause damage to lungs, skin and the nervous system. As well as those who already suffer from respiratory or skin problem, those most susceptible to the effects of mould are babies, children and the elderly.

Preventing mould on windows

There are 2 leading contributors to black mould forming around windows or on window sills: leaks and condensation.

If water is leaking from the outside onto the window sill, then it’s likely that the window frame is damaged and needs repairing or replacing altogether. When it comes to condensation, it’s all about reducing the amount of moisture in the air around your home, and there are several things you can do:

  • If you have single-pane windows, replace them with double or triple-glazing which are both much more resistant to black mould.
  • Keep the window vent (trickle vent), found at the top of windows to let in air from the outside, open to ensure maximum ventilation throughout the home.
  • Make use of extractor fans when cooking in the kitchen and washing in the bathroom.
  • Move houseplants away from the windows as they release moisture into the air.
  • Purchase a dehumidifier which will extract moisture from the air.
  • Open up your windows to keep your home well ventilated – only when it isn’t too cold though.

So, whether you’ve discovered black mould around uPVC, timber or aluminium windows, by adopting the above advice, you’ll greatly reduce the risk of mould returning to the area.

In the case that mould has caused too much damage to your windows, then the best solution may be to replace your windows. Finding the best installers for the job and requesting their quotes can be a time consuming task. That is, unless you do it with GreenMatch.

We can provide you with up to 4 quotes from top-rated installers in your area. You can then compare their quotes to find a good deal. Our service is free and comes with no obligations.

Get your best deal
Quickly compare 4 FREE quotes
  • Quotes from local engineers
  • Payment by finance available
  • Save up to £170 per year

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon
Call us to get quotes
We will get you the best deal

How to remove black mould

Before looking to remove the mould, you should find the cause as it will only keep coming back otherwise. When it comes to black mould around windows, a common cause is damage to the frame.

You should contact a professional to either repair the window frame or carry out a replacement, depending on how severe the case might be.

You can remove mould yourself but the NHS recommend to only do this if the mould covers an area smaller than 1 metre squared. If the mould has spread beyond this or the cause was found to be anything to do with sewage or contaminated water, always contact a professional.

Before starting, protect yourself by wearing goggles, rubber gloves and a mask that goes over your mouth and nose. It’s also a good idea to open up the windows for ventilation but keep doors closed to prevent spreading.

What you’ll need: A bucket, washing up liquid, rubber gloves, goggles, a mask, 2 rags, a plastic bag and either cleaning wipes or a hoover.

Step 1: Fill a bucket with water and washing up liquid
Step 2: Dip a rag into the soapy water and wipe. Don’t brush the mould around as this will cause it to spread.
Step 3: Once removed, use the dry rag to wipe the damp area of the wall and remove any moisture.
Step 4: Throw both rags away.
Step 5: Wipe down or hoover the surface where the mould had been.

If there were any clothes or soft furnishings in the area where the mould had spread, then you should put them into a plastic bag and take them to be professionally dry cleaned or throw them away if you’d rather.

How to remove window mould with vinegar

When aiming to get rid of mould around your windows using vinegar, you should always wear gloves to avoid irritation.

Step 1: Fill a spray bottle with white vinegar. Alternatively, wet a cloth with the vinegar and wipe.
Step 2: Thoroughly spray the vinegar over the mould.
Step 3: The vinegar needs time to break up the mould so leave if for 1 hour.
Step 5: Use a scrubbing brush and warm water to scrub away the mould.
Step 6: Wipe the surface down using warm water and leave the area to dry out.

If the mould reappears, try the whole process again. You might also want to combine vinegar with other products such as baking soda or salt to increase your chances of successful black mould removal.

Wooden window mould

Mould on a wooden window frame can gradually lead to it deteriorating. Wood holds onto moisture, making it the ideal material for black mould to form and grow.

To combat this, you might want to consider painting or staining the wooden frames and giving the joints of the frames a good clean to ensure they’re free from dust and moisture.

How do you get rid of mould on window sealant?

If you notice mould around the window seal you can first try cleaning the affected area. If this doesn’t work you’ll need to completely remove it and then reapply new sealant. This is important because if cleaning the sealant doesn’t work, reapplying it will be the only thing that will deal with the root cause of the window mould, which if not resolved can lead to more serious problems further down the line.

How to clean white silicone sealant around your windows:

  • First, start by rubbing a white vinegar and baking soda paste into the sealant. The white vinegar works by killing the mould spores, while the baking soda will help to remove any stains.
  • Let the paste sit for about 10 – 15 minutes, then use a scrub brush or sponge to remove it.
  • Once the paste is gone, rinse the area with clean, warm water and then dry it thoroughly.

To remove the old sealant:

If you’ve cleaning the sealant and window frame but see even the slightest sign the mould is returning, you will need to remove and replace the sealant completely. This isn’t as hard as you may think and will be the best option when it comes to preventing any mould around windows from forming in the future.

  • Start by using a putty knife or scraper to remove as much of the old sealant as possible.
  • Next, use a damp cloth to wipe away any remaining residue. If necessary, you can use a mild abrasive cleaner to help break down stubborn grime.
  • Once the area is clean, dry it thoroughly with a cloth or paper towel.

To apply new sealant:

  • Use a caulking gun to apply fresh silicone or acrylic-based sealant around the perimeter of the window. You can also consider anti-mould window sealant for future prevention.
  • Smooth it out with your finger or a putty knife, then allow it to dry for the amount of time specified on the product packaging.

Get free window quotes for repair and replacement

If one or more of the windows around your home are letting in moisture that keeps leading to mould then you should hire a professional to repair or replace them.

Complete our simple online form with details of the work you need and we’ll put you in touch with trusted window installers in your local area. You’ll be contacted by up to 4 installers who will each provide a quote for the work you outlined in the form. This allows you to compare the quotes and give you the greatest chance of finding the best deal for your home.

Get your best deal
Quickly compare 4 FREE quotes
  • Quotes from local engineers
  • Payment by finance available
  • Save up to £170 per year

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon
Call us to get quotes
We will get you the best deal

Frequently asked questions

How It Works
Answer a few simple questions
Describe your requirements by answering some super quick and easy questions
Talk to installers
Up to 4 installers will get in touch with you directly
Receive up to 4 quotes
Compare quotes and select the best option for you
Become a Partner
Become a Partner We strive to connect our customers with the right product and supplier. Would you like to be part of GreenMatch?