Musty smell in the bedroom you can't put your finger on? The causes could be serious

If there's a musty smell in the bedroom, don't delay investigating. It could be pointing to a serious problem with your house

Musty smell in the bedroom
(Image credit: VisualCommunications/Getty)

Is a musty smell in the bedroom keeping you awake at night? Or simply ruining the relaxing haven you'd hoped to create when furnishing the space? A musty smell could be down to something quite simple, but its really not worth putting off looking for the source of the bad smell, as it could be indicating a serious problem, which will require some proper investigation (and potentially repairs). 

In fact, a musty smell in the bedroom should be treated even more seriously than whiffs coming from the bathroom or kitchen, where the drains/waste pipes are usually the problem. 

Let's assume that your bedroom is clean and tidy, but smells like mildew. What could be the underlying reason? We say, all of the below are worth considering. 

1. That musty smell? It's probably the carpet

Carpets are notorious for holding onto moisture and can begin to grow mould relatively quickly. This applies both to natural and synthetic piles, although natural wool carpets are especially prone to mould. 

A good way to check whether there is mould growth is to look at the underside of your carpet in areas that are around windows, under radiators, and anywhere else that could have a leak or condensation that's dripping down and into your carpet. 

You could also be dealing with a leaking pipe under the floorboards, in which case your flooring will need replacing. You can try to remove mould from your carpet depending on how bad it is, but it may be best to just replace it, preferably with a different type of flooring.

2. Musty smells in bedrooms caused by leaks

If there is any plumbing that goes through your bedroom, you could be dealing with a leak in a wall or under the floor. This is especially likely if you have an en suite, or your bathroom is right next to your bedroom. And – if you live in an old house with idiosyncratic plumbing, you're likely to be surprised by how the pipework is fitted. Check for any areas around the walls that have discolouration, warping of paintwork or wallpaper, and/or feel soft to the touch. You will need a professional plumber to fix the leak. 

3. Mould is growing in your walls

This sounds a bit scary – and it actually is, because mould growth in walls will need some serious treatment (which will probably require you to move out for a little while), and is a health hazard. Particularly in rented properties, mould growth is sometimes simply painted over, which is just about the worst way to deal with it. 

If you suspect this to be the case, watch out for areas on your walls that look sweaty with condensation, or irregular surfaces. Eventually, of course, mould will start to show through the paint as well. If in doubt, and you are renting (and have an uncooperative landlord), contact the environmental health department of your council, who'll be able to investigate the issue for you.

4. You have a leaking roof

If yours is a loft or attic bedroom, you could be dealing with a leaking roof that is damaging the ceiling, which is growing mould in the process of absorbing the water. Eventually, the ceiling will collapse in the area of the leak, so this issue will need fixing asap. Look for an areas in your ceiling that have changed colour. 

5. How to prevent mould growth in the bedroom

Say you've identified and fixed the problem – you will now want to make sure you never have to deal with mould in the bedroom ever again. How do you prevent a reoccurrence? Provided that there are no further structural issues beyond your control (new roof or plumbing leaks), the following measures will prevent new mould growth in a bedroom prone to damp:

  • Insulate walls before wallpapering/painting: wall insulation will ensure that your walls are airtight and don't absorb moisture, which can then be trapped with wallpaper/paint;
  • Regularly service radiators: find out how to bleed a radiator in our guide;
  • Make sure your windows are in good repair and aren't producing excess condensation (this will turn into mould on your windows eventually). If you do have this problem, read our advice on how to reduce condensation
  • Invest in a dehumidifier – we have a buyer's guide to the best dehumidifiers you can buy.

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Anna is a professional writer with many years of experience. She has a passion for contemporary home decor and gardening. She covers a range of topics, from practical advice to interior and garden design.