Sterling Timber and Damp - Damp and Waterproofing

Damp can be a problem even in modern buildings. We are sealing ourselves more and more into our houses, which is good in the way that heat stays in and our heating bills go down, but can be bad in the way that moisture also stays in the house and can lead to condensation problems.

In older buildings, rising damp caused by the wicking effect of porous building materials can lead to serious structural problems. This can also contribute to the condensation issues by adding to the overall amount of water inside the house, which eventually turns into condensation.

Penetrating damp literally seeps in through the fabric of the building. Damage, wear and tear, surrounding areas, gardens and porous materials can all contribute. As well as routine maintenance, the choice of the right exterior treatment can be a big help, as can rendering or pebbledashing, or even just making sure your brickwork is correctly pointed.

Before attempting a cure, understand the problem

The problem with a lot of damp cases is that the symptoms of one kind of damp can be very similar to another. This can often lead to a mis-diagnosis, which could mean you pay a lot of money for a treatment that is not appropriate for the cause of your damp problem.

To make sure that you get the right treatment for the real cause of your damp problem, call Sterling Timber and Damp on 0800 136 874 or email us by clicking in the header of any page. Who knows? It could save you a small fortune.

Sterling Timber and Damp - Rising Damp

Rising damp (or Salt Damp, as it is known in many parts of the world) is not the most common form of dampness encountered in buildings; this is left to condensation. However, a high proportion of older buildings are affected by rising damp to some degree or another.

Rising damp in buildings occurs when water from the ground rises up through the bricks and mortar of a building by a process loosely termed as 'capilliarity' or 'wicking'. In simple terms, the water rises up the wall of a building in the same way that oil rises up through the wick of a lamp.

The height to which the water will rise depends on several factors including pore structure of the bricks and mortar and the rate of evaporation. Masonry containing a high proportion of fine pores will allow the water to rise higher than a coarse pored material.

Ground water contains soluble salts, the most significant of which are chlorides, nitrates and sulphates. When rising damp occurs, these pass with the water up the wall and are left behind when the water evaporates. Over many years of active rising dampness large quantities of these salts accumulate within the masonry and decorative surface, most becoming concentrated in a general 'salt band' towards the maximum height of rise. Both chlorides and nitrates are usually hygroscopic, (i.e.they can absorb moisture from the surrounding environment) and, in general, the greater the amount of salts the greater the absorption of moisture - especially under humid conditions. Thus, even though rising dampness may have been controlled by the insertion of a remedial damp-proof course these salts alone can cause the wall and any contaminated decorations to remain damp. It is for this reason that specialist replastering is such an important aspect of rising damp treatment.

Treatment of rising damp

Treatment of rising damp (known as 'damp-proofing' or 'dampcoursing') typically involves the installation of a chemical DPC, such as Dampcheck Plus using specialist injection equipment, followed by replastering using a salt retardant additive. However, with the introduction of damp-proofing creams, the process has now been simplified. The process is based on a high-strength damp-proofing cream that is injected into holes in the masonry, often without the need for an injection pump.

Sterling Timber and Damp - Penetrating Damp

Penetrating damp is moisture that penetrates the structure of your building. Causes vary widely and can include leaking roofs, gutters, drains and pipes, cracks and gaps in rendering. Moisture can seep through rotten or badly sealed door and window frames, through bad or missing pointing or even through porous stone and brick work. Even something as innocuous as a raised flower bed can contribute to the ingress of water.

An incorrectly sloping path or yard can increase damp problems when rain water flows towards and/or collects against the wall.

Dampness from the outside penetrates all the way through your walls and there are a number of factors that affect how long this process can take:

• The porosity of the wall. Porous (old) bricks, sandstone walls or walls with bad pointing will have more moisture penetration than walls of engineering bricks or with sound hard rendering.
• The width of a wall. Moisture will take longer to get trough a thick wall than trough a thinner one.
• The construction of a wall. Cavity walls will have fewer problems with penetration than solid walls. Cavity wall insulation can increase chances of penetration again.
• The amount of moisture. The more moisture, the more chances of it coming through.
• The length of time between periods moisture penetration. The longer the period in which it can dry out again, the more chances of moisture not getting through.
• The living habits of the occupiers. If the property is inadequately heated or ventilated the chances of penetration are higher.

Dealing with penetrating damp

Keeping the obvious things like roofs and gutters in good repair is a good start, and taking a good look around the outside of the building to make sure there are no obvious sources of water being directed towards the building is also a good idea.

Keeping brick walls properly pointed can help as can exterior treatments, rendering or pebbledash, which can help to seal porous brickwork or stone and prevent the wicking of moisture from the outside.

With many years of experience in fending off penetrating damp, Sterling Timber and Damp can offer sound advice, a straightforward quote and efficient application of many popular, effective treatments. Call now on 0800 136 874 to talk over any concerns you may have about penetrating damp.

Sterling Timber and Damp - Condensation

Condensation is the most common form of dampness in the UK. As our houses become more and more 'sealed' with better insulation and double glazing, fire places are blocked off, draughty windows and doors are replaced, moisture has no way to escape. To make matters worse, we produce more moisture by doing more laundry and having more baths and showers. An average person is responsible for about 4-5 litres of moisture par day. With so much trapped moisture in the atmosphere of our homes, it is hardly surprising, esepcially in winter months, that condensation starts to affect the building.

The principle of condensation is very simple. At any temperature air can hold a certain amount of water vapour. The warmer the air, the more vapour can be held. When warm moisture filled air cools down it will reach a critical point where it can no longer contain the moisture, which is then released as a condensate. Most commonly, this is observed at the interface between the warm air and a cold surface, e.g. window or outside wall. If that surface is non porous, e.g. windows or tiles, the water will deposit in the form of droplets. However, when the surface is porous, like brickwork or plaster, the water can start to cause problems because it is unnoticed and absorbed by the plaster and brickwork.

Over time, walls will become damp and mould may start to appear. Very often this will be noticed around windows, in recesses or corners, in bays with a high surface area to volume ratio or behind wardrobes against outside walls. Often the mould is black, but other colours are also frequently seen.

As time goes on, the integrity of plaster and brickwork can be compromised through condensation, paint will start to peel, window frames and other woodwork can develop wet and dry rot. Unpleasant, musty smells can emanate from areas of mould caused by condensation. Many people point to the environment that encourages bacteria and fungi as being a source of infection and a trigger for many allergies and respiratory problems such as asthma.

Treatment of condensation

There is not much that can be done about the spores of mould that exist in the air everywhere, apart from taking away the thing that they need most to survive - moisture. To keep down the amount of condensation generated, ventilation is usually the key. While it is hard to keep windows open for reasons of comfort or security, ventilation is possible, the type of insulation used, ventilators and semi-permeable membranes installed as well as building materials used in repairs can all help in cutting down condensation.

If your building suffers from other kinds of dampness, such as rising or penetrating damp, this can exacerbate the condensation problem by adding to the amount of liquid inside the building that can evaporate. This can often lead to confusion on the part of less expert damp treatment companies who may offer to treat the symptoms without considering sufficiently the underlying causes.

For an unbiased answer and an appraisal of your problems based on long experience, call Sterling Timber and Damp on 0800 136 874 or click in the header of any page to email us.