How‌ ‌Can‌ ‌You‌ ‌Tell‌ ‌if‌ ‌Mould‌ ‌is‌ ‌Growing‌ ‌Behind‌ ‌Walls?‌ ‌

In most cases, homeowners don’t see mould before it spreads out of control. This explains why people often refer to mould as an “unseen problem.” The sooner you can detect and deal with mould in your home, the better position you’ll be in. You’re far less likely to deal with the burden of health issues and financial costs if you can spot it early.

Here are the signs you can follow to tell if mould is growing behind the walls of your home.


Mould grows indoors where moisture is present. Some things that cause excessive moisture buildup are:

  • Poor ventilation in bathrooms that are used daily for showering or bathing
  • Flooding due to weather conditions
  • Plumbing problems

Water problems like leaking pipes may trap moisture inside your walls. Even in these cases where leaks are visible, moisture can get inside walls, providing the mould’s conditions to grow. A critical thing to check is if the surface of your wall feels wet or damp.

Visible Signs of Mould

The appearance of your walls may change significantly if there is mould growth behind them. Discolouration in your walls is an ample warning signal that’s typically easy to spot. In extreme cases, your wall could even be deteriorating. Paint or wallpaper can crack, bubble and peel because of moisture and mould growth. Moreover, if the walls are bowed, bulging or warped, they most likely contain moisture. 

Another visible sign of mould is water stains or water damage. If these have been on your walls for a long time, there’s a strong possibility of mould growth. We recommend checking your home at least monthly for these vital signs. As mentioned, discovering mould early can make a big difference in the impact.

A few of the famous places in your home where mould loves to hide are:

  • Around window sills
  • Behind washing machines
  • Behind air conditioners
  • In bathrooms
  • Behind wallpaper

These are the places you should be giving the most attention to when you’re checking for signs of mould.

Musty Smell

If you aren’t able to visibly spot any signs of mould, you’ll probably still be able to smell it. A strong, musty odour is given off by mould. We describe it as an earthy smell that you would find in a damp forest.

One tip for discovering mould is getting down and smelling electrical outlets. Smelling through these outlets allows you to sniff out mould behind your walls more easily. As you may know, outlets have clear access to space behind your home’s walls. It sounds weird and like a lot of work to smell electrical outlets in your home. However, we must remind you of the cost that comes with undiscovered mould.

To be sure of mould growth behind your walls, contact a professional for a free inspection of your home. There is a wide variety of testing that can be done to confirm if you have a mould infestation or not. The type of mould testing chosen depends on your unique situation.

For more information on the signs of mould, you can visit the Government of Canada website. In the meantime, we have another blog written on indoor mould growth and what you can do to prevent it.

Tags: , ,

Comments are closed here.