A first time buyer's guide to damp

A first time buyer's guide to damp01/03/2016

By EnviroVent

Damp is one of those horrifying words that keeps potential homeowners awake at night and rising damp can indeed be a serious problem that can cost you a huge amount to fix. If you’re a first time buyer, you would do well to educate yourself on the tell-tale signs of damp, but it’s also worth bearing in mind that there are things you can do.

Damp doesn’t mean the end, so even if you’ve already bought a house before spotting the warning signs, don’t throw the towel, or towels, in yet. If you haven’t bought it, you can get the damp checked out and, if it’s an easy fix, you might be able to negotiate on the price and even use those damp patches to your advantage. With the help of a house heat recovery, or other remedial works, the damp can be a distant memory.

So how do you spot damp? Well there are different types and, unsurprisingly, they come with their own warning signs. The main types are rising, lateral and penetrating damp, with condensation and mould also forming part of the broad spectrum.

Rising damp

Rising damp is the one that fills most house buyers with fear. Without using any equipment, you can use certain visual and touch signs to help identify rising damp. You can spot rising damp due to tide marks on the wall, up to one metre high, which leave a residue of water and salts.

These areas are often darker and still damp to the touch, but even if the area is dry, it can still be an indication of a previous damp problem that has not been properly fixed. The plaster itself can crumble away if it is dry, or it can feel like paste if enough water has intruded. Wallpaper often peels from the wall and the skirting boards can show signs of decay.

Nails or screws in the skirting board can also show excessive signs of rust and there is often a damp and musty smell present.

Lateral damp

This bears many of the same hallmarks as rising damp, but the point of intrusion is often from an outside wall, leaking pipes, missing tiles and even overflowing gutters. The damp can appear at any point on the wall.

Look out for dark, damp patches on the wall and ceiling, any woodwork that shows signs of damage and for mildew in crevices. Crumbly, wet plaster is also a dead giveaway and any spores should be a clear sign that damp is in the house.

Penetrating damp

This type of damp also originates from outside walls and can be seen on the outside of the house, with patches of damp that increase in size after heavy rain. Check walls that are more exposed to the elements and the roof, ceilings and interior walls that correspond to the external patches to decide if the damp has intruded to a significant extent.

It isn’t just the damp you’ll have to rectify if you find its presence, as leaky pipes and faulty joists in the windows and walls can often be the problem and that can be expensive to fix. It is more likely an issue with the brickwork, though, and dislodged or even damaged bricks or render can be the issue.


If you spot signs of condensation then you might dismiss it as simply being part of an older house, but it can be the sign of a more serious issue. Excessive condensation is a sign that there is simply too much water vapour inside the house. That comes from somewhere, which is normally an indicator of some kind of damp issue or poor ventilation, which is another issue that you want to identify before you buy.

Black mould is a potentially life threatening issue for a young child, the elderly or anybody with a pre-existing lung condition. Look for isolated spores on the ceiling and walls and also examine the window and doorframes carefully. A smart seller will wipe them down before showing the house, but if you look closely, you’ll see tell-tale signs where a sponge or brush simply could not reach.

Whole house heat recovery

Minor cases of damp can be easily treated and then controlled with an EnviroVent whole house heat recovery system, which ensures a steady flow of air through the property at a controlled temperature. The system controls humidity and focuses its energy on drawing moist air from rooms like the kitchen and bathroom to a central unit, where it is effectively dried over a heat exchanger, before it passes through ducts to the outside of the house.

Fresh air is drawn from the outside and passed over the heat exchanger to replace the air that is ducted out with dry air that helps maintain a healthy balance in your house and remove any lasting traces of damp. Combine this with remedial work to fix any water ingress on the outside and you'll have a damp-free home before you know it.

Before you buy, you should always invest in a proper survey. All the amateur sleuthing in the world can’t negate the need for a qualified professional, especially when it comes to something as serious as a house purchase. Surveys are expensive, of course, so if you can rule out a house without resorting to the survey then that is still a victory of sorts, but don’t think you can avoid the expense altogether.

Even with a new house there could be issues, so if you want to be safe then a New Build Snagging report could be an option. The most basic general survey is a Condition Report, which is useful for a modern house with no obvious faults. This is a simple check, so if you suspect damp then it isn’t a safe option.

If you have concerns then you should opt for a Homebuyer’s Report, which deals with issues like damp and subsidence. It also covers issues such as outstanding and necessary repairs and, although it is a surface level inspection that does not require the removal of floorboards, it should uncover most issues.

If you know you are taking a gamble on an older or rundown property then a full Building Survey is almost certainly a good idea. This is the most comprehensive survey and will include checks under the floorboards and in the attic, as well as listing any major defects.

Before you get to this stage, though, you can and should carry out your own inspection and decide if the damp has gone too far, or if it can be used as a negotiating point. Then the whole house heat recovery system can be all it takes to dry out the damp.

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