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Dampness coming through walls
Independent building surveyors
We are experienced, professional independent building Surveyors who are knowledgeable in carrying out structural surveys on all types, styles and eras of buildings. If you are moving house or having any property issues then an independent Surveyor can help provide a comprehensive survey report. Free phone 0800 298 5424Why does dampness coming through walls?
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English bond brickwork |
Flemish bond brickwork |
The other interesting fact about older brick walls is that they are often in a softer red brick and when they’re in brick or stone they are generally bedded in lime mortar. Both the softer red bricks can weather and so can the lime mortar.
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Red brick Victorian house |
Over the years other solutions have been rendering which was alright whilst we used a lime mortar but tends to be a problem as it cracks and can cause deterioration where cement mortar is used. We also tend to find that the detailing isn’t as good with modern render and they miss things like the drip details over the windows and the bell mouth to the base of the render.
Drip detail over windows |
Bell mouth detail at base of render |
In the 1960’s/1970’s such things as pebbledash render was used, which was a form of rendering normally in cement, possibly with some lime with pebbledash applied to it. It could be machine applied so the job was only semi-manual which meant it was a lot quicker and was sold as the latest things to prevent dampness.
Other things that have been used over the years are such things as stone cladding, which is basically stuck to the brickwork. It does offer a protective layer but can look strange where the rest of the row of houses are in brick with one in stone.
Repointing in cement mortar can be one of the worst ways to stop dampness in a wall. First of all it doesn’t deal with the actual cause of the problem because an older wall needs to ‘breathe’ and it allows water into the surface and then it dries out during warmer and windier weather. Unfortunately a cement mortar where it’s used for repointing simply blocks the joints and means that the water can only come out through the brickwork which tends to cause the face of the brickwork to deteriorate.
The second worst thing to do to an old wall is to paint it with a modern paint. We were recently disheartened on a wall of one of our properties that we’d been leaving for some time to allow the cement render to come off on its own (when we say some time we had been doing this over a period of around five years) and then the person living in the house decided to paint the exterior without advising us and they had used a plastic based paint, which effectively smothers the wall and causes all sorts of problems with old soft red brick, which is what this was. Unfortunately unlike the repointing in a cement mortar, painting in a plastic paint is very difficult to get off and tends to cause dampness into a property.
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Blistering to plastic based paint. Damp meter readings show how levels of dampness. |
The whole problem with dampness in a property is that people then often contact ‘specialist damp proof companies’. We say specialist damp companies because many of them we would argue are just selling chemicals that they inject into a wall and chemicals that they put into the external render and internal plaster. We have seen all sorts of problems with these walls where the dampness returns.
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Blistering to plastic based paint. Damp meter readings show how levels of dampness. Knife test on skirting board. It goes right through as the timbers are deteriorating |
As you will probably guess we would always recommend you have a building survey (often known as a full structural survey) to understand not only the effect of the dampness, as most people can see dampness, but also the cause of the dampness.
Newer buildings will tend to have a Stretcher bond brick construction.
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Stretcher bond brickwork
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Where the air gap between the outer bricks and the inner wall has been filled accidentally by poor bricklaying, where the mortar has fallen down the middle. This can lead to dampness patches internally. |
New build property
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The other problem we’ve come across is where insulation has been incorrectly added to a cavity wall and this cause caused the dampness to transfer from the exterior of the property to the interior of the property. Again unfortunately the need to sell, sell, sell by the insulation companies means that sometimes they don’t carry out the correct checks and add insulation regardless, causing all sorts of problems.
We sometimes find that dampness can get into properties where there is a change in level of the land. We refer to this as a sloping site and is where the rear wall of the property effectively becomes a retaining wall of the earth and any ground water within it. This can cause dampness to get into the property.
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High ground level around a property. Plants are growing where there is dampness. |
Sloping site sketch |
We shouldn't forget that it was common to have a suspended timber floor like we have shown in the adjoining sketch. Underneath the suspended timber floor you had air movement from the airbricks that were outside the property. This air movement often included air movement up between the floor boards as we didn't have wall to wall carpet, we simply had a carpet for the middle of the floor and the air movement was considerable underneath the property. |
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Suspended timber floor |
We have a wealth of knowledge and experience as independent surveyors if you require a building survey or structural survey.
If you would like us to send you a copy of one of our surveys we are more than happy to do this although we fully appreciate all properties are unique therefore making all our surveys unique and tailored to your individual needs.
We have every confidence in our surveys and believe there are no other comparable surveys out there in the UK property and surveying market.
Having a survey carried out on the property by an independent chartered building surveyor will give you extra peace of mind.
All are surveyors are members of the Royal Institution of Chartered Surveyors (RICS) and Independent Surveyors and Valuers Association (ISVA).
Within our reports we utilise a system of ovals and circles to highlight problem areas or characteristics within a property to better explain the issues. If this does not explain the issue completely then we can also use one of our sketches that have been commissioned exclusively for us for use in the reports.
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Gilleting stonework sketch |
Gilleting between stonework |
We recommend you meet us at the property during the survey so that we understand exactly what you require from your survey report and so we can answer any questions you may have.
Here are a few articles we recommend you read regarding dampness and walls.
How, in our opinion, insurance companies deal with cracking
Condensation, mould and air movement in houses
To see more surveying articles go to our website www.1stAssociated.co.uk or phone us on 0800 298 5424.
We hope you found the article of use and if you have any experiences that you feel should be added to this article that would benefit others, or you feel that some of the information that we have included is wrong then please do not hesitate to contact us (we are only human).
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