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Property Surveying Blog
June 15, 2020

Damp in Properties

Written by Mohbin Malik

In this week’s blog post, I am going to be discussing damp in properties. Damp is a common problem for most property owners or property occupiers therefore knowing the facts is a must.

The most common types of damp found in residential properties are condensation, penetrating damp and rising damp. I will be looking into each type of these defects and providing simple solutions and tips on controlling it within your home.

What is Condensation?

What is Condensation?

Condensation is the process by which water vapour in the air is changed into liquid water. In other words, the water in the air, a gas known as water vapour, from a hot shower, cooking hob or simply over-occupancy. When this gas meets a cold surface like a mirror or an external wall, the water vapour condenses and turns into a liquid form. You would notice it as moisture or beads of water and fog that has formed on the mirror or wall. This happens when moisture is trapped and is caused by insufficient ventilation. It is the most common type of damp and is the easiest to resolve if caught early.

You can cut down on condensation or even be able to eliminate it by ensuring that rooms are well ventilated, windows are kept open when showering or drying clothes and investing in a portable dehumidifier which can be run overnight and when drying clothes can manage humidity and dry clothes faster.

If your property has double glazing, it is important to remember to open the windows incrementally, even in the colder months. When the room is hot and the external walls are cold, it is an ideal breeding zone for condensation.

What is Penetrating Damp?

What is Penetrating Damp?

Penetrating damp is caused by water leaking through walls. This type of damp moves horizontally and may expand across your walls or ceiling. It is usually caused by wider problems in a building, such as faulty guttering or roofing or cracks on walls. It can also be caused by internal leaks, such as leaking pipes underneath fitted showers, sinks or baths.

It often occurs in the wetter months and may just be the result of persistent rain and a poorly maintained property. Properties are prone to defects with roofs, brickworks, cavity insulation or windows all needing regular maintenance and attention. Depending on the issue, you can look at having brickwork re-pointed, adding sealant to walls and windows and even rendering the whole property to prevent water seeping in.

Whatever the solution, make sure the property has a well-established plan. It is also worth bearing in mind that maintenance doesn’t need to be a costly endeavour. Clearing the gutters annually and keeping the brickwork free from vegetation are both very easy DIY solutions that can be done over a weekend.

What is Rising Damp?

What is Rising Damp?

This type of damp tends to affect ground floor rooms, it is caused by groundwater moving up through a wall or floor and is usually prevented by gravity from soaking up much further than a metre up the wall.

The biggest signs of rising damp are tide lines of yellow and brown around the bottom of the wall, the damp floor under carpet and black mould and damp just above the skirting board.

With any property, it is natural for walls and floors to allow a little water in, but it’s usually stopped from causing damage by a barrier called a damp-proof course or damp-proof membrane. A damp-proof course is a waterproof horizontal strip, usually made of plastic or bitumen felt, built into the wall at a minimum height of 150mm above ground level. It is worth noting that in older properties such as the 1900s or 1930s, it can also be a slate tile laid horizontally across the brickwork.

A damp-proof membrane is a sheet of material that’s impervious to water, which is laid underneath the floor. This is connected to the damp-proof course so that the house is effectively sealed and protected from groundwater.

Rising damp is usually due to an issue with your damp-proofing; for example, you don’t have it, it’s breached or it stops below ground level.

Ventilation is also important. Making sure air can circulate freely between the cellar (if you have one) and the ground floor. Removing vinyl flooring or rubber-backed carpets and replacing with a breathable material instead. This will allow fresh air to circulate and dry out the damp. Also, making use of extractor fans and dehumidifiers to keep the humidity level in your property low.

If the above has been tried, tested and failed and you believe your home or property is suffering from rising damp, then you need to confirm your suspicions with a professional diagnosis. You should opt for a qualified damp surveyor or rising damp treatment specialist. They will carry or a rising damp survey, complete a thorough analysis and then recommend a treatment based on their finding.

Rising damp is a costly one to repair, the ground level may need to be reduced or if that isn’t appropriate an injection damp proof course may need to be installed.

In any event, always consult the experts!

If you have a damp issue that you would like to discuss with our team of Surveyors, give us a call now and we will be more than happy to assist you. A Defect Analysis report could be a fantastic way to diagnose and address this issue!