How to deal with mould, damp and rot
Providing a safe environment for your tenants is obviously a focus for any landlord, and that means spotting and dealing with damp problems.
Left untreated, damp can cause serious damage to the structure of your property, including rotting timbers - potentially reducing your property’s worth and your ability to rent it out. More importantly there are also serious health problems associated with damp, including from living with the mould that thrives in damp conditions.
Swift action will end up saving you time, money and your tenants’ health.
What are the common health problems associated with damp and mould?
Who is most at risk?
- Elderly people
- People with skin problems such as eczema
- People with existing respiratory problem such as allergies and asthma
- People with a weakened immune system - such as those having chemotherapy
What is damp?
Damp refers to any unwanted excess moisture, water or condensation in your property. Sometimes it’s hard to spot damp problems, which can often get worse and end up causing secondary damage.
What is mould?
Mould is a type of fungi which grows best in damp conditions, and spreads by producing spores. It’s often one of the signs that you’ve got a damp problem. Mould can produce allergens and irritants, and in some cases harmful toxins.
What are the common causes of damp?
- Internal and external slow water leaks from dripping pipes or damaged guttering
- Rising damp - a common term for water or moisture travelling up through the walls or structure of the property from the ground
- Inadequate ventilation or too much steam in the air – common occurrences are when cooking, drying clothes inside or showering
- Poor maintenance – such as missing slates in the roof, cracks in the render or defective pointing can all provide a way for water to get in and damp problems to start.
It is important to note that damp isn’t just visible on walls. It can also be found on floors, ceilings, doors, around the windows and pipe-work of any home. Looking out for the warning signs could help you prevent more complicated problems.
Simple tip: Your tenants who live in the property every day may not spot or report mould of other warning signs of damp. There is no substitute for regular inspections, which are the best way to ensure small issues are dealt with before they become big – and expensive – problems.
How do you spot damp?
- Damp musty smell
- Black spot mould on walls, fabrics and between grout
- Water droplets collecting on cold surfaces such as windows, windowsills, mirrors and tiles
- Condensation between double glazing
- White fluff
- Salt residue
- Skirting boards or beading becoming brittle or coming away from the walls
- Peeling or bubbling paint or plaster
- Dark, discoloured or brown marks
- Springy feeling underfoot – an indication of damaged floorboards
- Wet patches
What are a landlord’s responsibilities when it comes to damp and mould?
What are the different types of damp?
- Condensation damp
Condensation appears when excess moisture in the air comes into contact with a cold surface, like a window or wall. It can lead to mould growth and is made worse by inadequate ventilation, heating or insulation.
- Penetrating damp
Penetrating damp is caused by water penetrating the fabric of a building from the outside – in, because of a leaking pipe, missing slates or rotten windows, for example.
- Rising damp
Rising damp happens when ground water or moisture travels up from the ground, through the brickwork.
- Construction damp
Construction damp is where dampness is caused by a problem in how the property was designed and tends to cause secondary damage to the building.
How to deal with damp
Dealing with condensation damp
This is the easiest type of damp to deal with. It can usually be tackled by improving ventilation – for instance getting a fan or a vent installed, or by checking heating and insulation. A consistent low heat in your rental property over winter could solve a condensation problem.
Dealing with penetrating damp
Penetrating damp is usually a matter of maintenance, and fixing the leaking pipe, guttering, or roof causing the issue. You’ll then need to repair any secondary damage, for instance by redecorating. Good ongoing maintenance and inspections should be able to prevent further problems.
Dealing with rising damp and construction damp
These damp problems will be harder to treat, and you’ll need to get professionals in to help you identify the source of the problem. It may be you need to repair or replace your damp-proof course.
A damp-proof course is a treatment which can be applied to your property to prevent damp occurring where a thin layer of waterproof protection is applied within the affected wall(s) of your property.
Over time a damp proof-course can become damaged, or it can be bridged – for instance by a plant or outbuilding next to it which creates an alternative route for moisture to travel round the damp-proof course and continue up your walls.
What is rot?
An untreated damp problem can lead to wet or dry rot, and could cause significant damage to your property.
Wet rot is a form of fungal decay which can weaken the timber and the structure of your property, eating away at floorboards, window frames, supports, roof beams and softs. Wet rot does not spread through masonry but will continue until the source of the moisture is removed.
Dry rot CAN spread through thick brick walls by travelling through mortar joints in search of more timber sources. It often grows in some not so obvious places such as under floorboards or in the loft.
What are the signs of wet rot?
- The first sign of an outbreak of wet rot are growths of what look like cotton wool or dandelion seeds on wood
- Timber can also look bleached, or become darker
- Wood will feel softer and spongier than in unaffected areas, and when it dries out it will crack along the grain and start to crumble
- Paint over affected wood will start to flake
- Localised fungus may start to grow on timbers
What are the signs of dry rot?
- The smell of dry rot has a distinctive earthy, soil-like or mushroom-like smell and will get stronger as the rot spreads
- You may notice concentrated patches of rust coloured dust
- The timber will be brown, dry, brittle and will often crumble in the hand
- When tapped wood will sound hollow and feel lightweight
- Fine grey cobwebs, known as hyphae, develop from dry rot spores and help it spread in the early stages
- Cotton wool-like cushions called mycelium are then produced by dry rot when it needs to spread to nearby timber
- In the later stages, distinctive yellow-brown mushrooms, known as fruiting bodies, appear, turning brown and red when mature, and ready to pump spores into the atmosphere
How to deal with wet and dry rot
It is vital to identify the source of water or moisture causing the dampness and feeding the fungus.
Once moisture is removed timbers can be dried out, and treated using a fungicidal treatment. Rotten timber can then be removed and replaced with timber treated with a preservative.
Of the two conditions, dry rot is by far the more serious, and may require substantial repairs. If you’re not sure whether you have wet or dry rot, call in the professionals to do a full damp and timber survey.
Don’t let damp, mould and rot but a dampener on your buy-to-let investment!
Know the signs, keep an eye on your property, and make sure any issues are dealt with as quickly as possible, before they become bigger and more expensive problems.