why is my ceiling going mouldy cover image

Why Is My Ceiling Going Mouldy?

Visible mould anywhere in your home is never a great discovery. However, when you see visible signs of mould in your ceiling, you’re in a bit of trouble. If you’re reading this article, you’re probably asking yourself, “But why is my ceiling going mouldy?”

What causes ceiling mould is usually a leaking roof or poor insulation. If left untreated, the leak and mould can expand and cause severe problems to your ceiling and in your roof cavity. However, with the right expertise and early detection, you can mitigate many ceiling and roofing issues that generally occur when mould on your ceiling becomes visible.


While small amounts of mould may seem harmless, as they grow, they are much harder to manage and could even be hazardous to your health. If you’re asking, “Why is my ceiling going mouldy?”, you’re going to have to work out what’s causing the growth of the bacteria.

why is my ceiling going mouldy

Mould usually appears on your ceiling or wall due to a leaky roof or issues with insulation and ventilation. In a damp, humid and confined environment, mould thrives and can spread rapidly. Mould will often present itself as a green or black stain that can be very difficult to remove.

You may also notice brown stains on your ceiling. A brown colour occurs when moisture issues are present, but no mould has grown. While no mould is good news, it is also essential to treat these issues as soon as possible. These stains identify areas where there are moisture issues and could provide the ideal conditions for mould to grow in the future. Additionally, moisture build in your roof and ceiling is never good. Not only does it mean that there is likely a problem with your roof, but over time it can cause significant damage and require costly repairs to address the issue. Whether it be moisture or mould, your best bet is to act on it as soon as you notice a problem.


While many sources online will provide you with adequate ways to clean the mould and even remove the stain on your ceiling. It is pointless to clean the surface without addressing the root cause of the problem. As these stains are caused by issues in your roofing, it is best to contact experienced roofing contractors. These contractors will be able to inspect your ceiling and roof, identify the causes of the problem, and develop solutions to fix them.

Often, a leaky roof is responsible for your mould issues. Many things can cause leaky roofs including, storm damage, old roofing material and compromised seals and sarking. Some leaks can be small and hard to spot without the eye of an expert roofer. If a roofer identifies a leaky roof as the problem, the next step will be to make all necessary repairs and seal the roof, so it is watertight and replace any water-damaged materials in your roof cavity.

Symptoms of mould from a leaky roof include:

  • Brown/Yellow discolouration on your ceiling
  • Circular shaped staining
  • Mould growing in a single region

Additionally, poor insulation and ventilation can contribute to moisture and mould issues in your building. Without adequate ventilation and insulation, it is easy for moisture to build, and humid conditions eventuate. Mould thrives in damp conditions. Most homeowners do not realise they have inadequate insulation and ventilation issues until mould begins to appear.

treating mould in roofing and ceiling

If the mould has been caused by increased humidity, roofers can dry out the ceiling using dehumidifiers and air conditioning devices. They will also determine whether the ceiling needs to be replaced or repaired and if any additional work is needed to improve the air quality and prevent mould from regrowing.

Symptoms of mould due to humidity include:

  • Mould growth is the most apparent at the edge of a roof
  • The ceiling is poorly insulated
  • The mouldy ceiling/wall is on the top floor


Now that we’ve answered the main questions of, “Why is my ceiling going mouldy?”, and “How do I deal with mould on ceilings?”, let’s talk about prevention.

There are a few things you can do to prevent mould from growing on your ceiling. The most valuable action you can take is to perform regular checks around your house. Regular inspections will allow you to identify small mould formations on ceilings or walls before they become a bigger problem. Checking for signs of mould or moisture issues is especially important in rental situations. When viewing a house, don’t forget to scan for any signs of mould or watermarks around the property.

Additionally, routine maintenance of your roofing, plumbing, and guttering will ensure there are no issues with water transportation in or around your house. Leaky pipes or clogged guttering offer perfect conditions for water to build up, and mould to grow. If you are looking for a professional inspection of your roofing and guttering, the contractors at Vertec Roofing are your go-to team. Whether you need a leaking roof repair in Canberra, a roof restoration in Sydney, or a simple gutter cleaning service, we’ve got you sorted.


With over 20 years of industry experience and a focus on customer experience, we are the most trusted source across Sydney and Canberra for all roofing needs. We can provide Sydney leaking roof repairsgutter repairs in Canberrafascia replacement or general roof inspections. Whether you’re experiencing mould on your ceiling, or you’d like some professional roofing advice, Vertec Roofing are your team. Get in touch with Vertec today to learn more about how we can help with your Canberra or Sydney property.

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