The difference between rising damp and condensation

The difference between rising damp and condensation21/03/2016

By EnviroVent

Easily confused, rising damp and condensation are both things which you might find in your home. However, while one can be relatively easily remedied before too much harm is caused, the other will need more time and investment to banish it from your home.

What is condensation?

Water vapour in the air can be naturally occurring from weather conditions, respiration from human beings, and even plants. You can’t see it, but it’s there in your home. The water vapour floats merrily around your house, and is fairly innocuous. It’s only when it comes into contact with something cold that it starts to become more troublesome.

When it hits something cold, like a window or a poorly insulated surface, the water vapour drops in temperature, and loses some of its strength. It can no longer hold onto its water content, and lets it drop onto the colder surface. This deposited water is what you see when you notice condensation. You can expect to see condensation on any surface where the cold air of the outside world comes into contact with the warmth of your home. Windows and thin, poorly insulated walls are the usual locations you can expect to see condensation.

Condensation can result in black mould. Black mould, or Stachybotrys, is a naturally occurring fungus which helps Mother Nature break down items such as vegetation and return it to the soil. Unfortunately, this mould does not recognise the difference between the inside of your house and a mouldy apple – it just finds the humidity provided by condensation.

What is rising damp?

Rising damp is different to condensation, although it may have the same appearance. Imagine a sponge being dipped into a bath tub full of water. Water travels up through the sponge as the sponge sucks the water in. House bricks placed onto damp ground behave in the same way as this sponge, sucking up the water from the wet ground around them, in an upwards motion, hence the name “rising damp”. Bricks and masonry keep on sucking up water until gravity dictates that it can’t carry itself up the masonry any more, usually at around 1.2 metres, and the damp levels just build up in the affected area.

Much like the black mould on condensation afflicted walls, the wet areas involved in rising damp also attract the spores of the Stachybotrys mould, and that may be the first sign you notice that you have a rising damp problem. You may also notice the damage from the outside of your home, with a tell-tale tide mark on the exterior bricks.

Don’t confuse rising damp with other common types of damp though. Ground floor level walls can suffer from a similar condition, penetrating damp. Common in cement rendered homes, or those where the cavity walls have been filled, penetrating damp is the result of trapped damp which cannot escape, or an increase in water vapour which overwhelms the few escape routes in a home.

If you’ve got a chimney, you may notice “salt dampness” from long-term water ingress. A giveaway is if you can see weeds and plants growing on your chimney stack, meaning there’s enough water there to support organism growth. Naturally occurring minerals and salts in the air travel through the wetness in the building, and appear on internal walls as brown staining.

The good news is that there are really simple products out there which can remedy condensation and damp problems, and the ventilation experts at Envirovent can help you install them to remedy any damp issues you have in your home. With filterless extractor fans for your bathroom and kitchen, or specialist loft based installations to keep the air in your house clean and mobile, damp and mould won't be able to build up. If the air moves, the damp cannot set in, and there is no way mould will find a home in your house. Speak to the team at Envirovent today to find out which solution is most appropriate for your house. Nobody knows ventilation like Envirovent.

Comments (2)

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Katie Anderson Tue, 5th April 2016
Rising damp can be really dangerous, and drastically effect the value of your home. You want to make sure that you correct these problems as fast as you possibly can so that it doesn't turn into a huge costly repair bill. Calling in the professionals as soon as you see the problem will help you treat it fast, and keep the value of your home high.

Hazel Owens Mon, 20th June 2016
I didn't realise that bricks could act like sponges and soak up moisture from the ground. While most of my house isn't made of brick, my chimney is. I'll follow your advice and check it for any signs of rising damp like weeds growing in the chimney stack. Thanks for the information!