Phone or Text David on 07751 738 843.

Thank you for visiting:

This web site has been created to inform the world wide web about the cause, symptoms and treatment of damp in buildings and to introduce my services in the above areas of London.

Your property is left Clean and Tidy:

With all projects craftsmanship and high standards of perfection are of paramount importance, works are carried out with a professional attitude and for your peace of mind your property is left: Clean and tidy.

Rising Damp Surveys:

If you have rising damp issues that may require a damp proofing treatment. You will notice damp patches, blistering paint and or plaster above the skirting boards. You may also have associated black mould and or white salt deposits.

Please email images if your property is in one of the above areas of London South West and after reading the table below you feel you have rising damp issues.

Damp Surveys not related to Rising Damp:

There will be a charge for a visit and verbal assesment of the issues. Please call for details.

Damp Surveys and works in Tenanted Properties:

I am very sorry but due to consistent issues, I no longer undertake surveys or works in tenanted properties, while they are occupied.

Evaluating your Damp Issues:

Works Undertaken:

General Building and Plastering works:

Please call David on 07751 738 843 to arrange an appointment. I am available to visit your proposed works on a day that is convenient to yourself from 8am to 10 pm. Sorry I do not plaster ceilings.

Damp Proofing and Plastering of Georgian, Victorian and Edwardian Properties:

I specialize in the damp proofing, plastering (not ceilings, sorry) and refurbishment of Georgian, Victorian and Edwardian properties.

Refurbishment of sash windows, repair of rotting door and window frames:

I also undertake the repair of rotting timbers in windows, doors, door frames, and floor joists.

Page Contents:

Rising Damp Surveys:  

Evaluating your damp issues:  

Introduction to Rising Damp:  

Introduction to Penetrating Damp:  

Introduction to Condensation:  

Further Reading:  

Glossary:

Site Links and Contents:

Building, Carpentry and Design Services:  

Plastering and Tanking Services:  

Basement and Cellar Conversions:  

Damp Proofing Treatments:  

Decorating following a damp proofing: treatment  

The cause and symptoms of Rising Damp:  

The cause and symptoms of Penetrating Damp:  

The cause and symptoms of Condensation and Black Mould:  

The Damp Proofing section illustrates how moisture from the ground is prevented from entering; and how it enters, a building. For further reading you may also like to read my articles about the cause and symptoms of rising and laterally penetrating damp.

Condensation and Black Mould:

If you have black mould which you know has been caused by condensation visit Mould Growth Consultants, who sell kits for the removal of black mould.

1: Rising & Laterally Penetrating Damp:   <

Rising and laterally penetrating damp issues usually effect pre 1920's Georgian, Victorian and Edwardian properties, which do not have a physical damp proof course. Or where the existing damp proof course has failed, been breeched or altered.

Symptoms of rising & laterally penetrating damp:

If present you will have one or more of the following symptoms on the ground floor above the skirting boards or in a basement or cellar.

• Blistering paint and plaster.
• Dark and damp patches on walls.
• Salt deposits, which attract moisture.
• Black mould growth.

Arrange a survey:

As you can see from the images opposite of poor Jo's kitchen in Teddington, rising and laterally penetrating damp is very distinctive. If you have any of the above symptoms above the skirting boards or in your cellar or basement please call David on 07751 738 843 to arrange a survey.

Please Note: The following section illustrates how moisture from the ground enters a building. The Damp Proofing section illustrates how moisture from the ground is prevented from entering a building.

Movement of moisture into a building:

The diagrams opposite illustrate the movement of moisture from the ground into the mortar beds, of a typical Victorian or Edwardian property with a 9 inch solid wall and sand and lime mortar beds; the mortar between the brickwork.

The mortar beds:

Although moisture does flow into the brickwork of a building via capillary action, the major movement of moisture from the ground; into a building, is via diffusion; into the mortar beds. The mortar between the brickwork. Acting like a sponge, the readily absorbing beds of sand and lime absorb moisture both:

• Horizontally: Lateral Penetrating Damp and

• Vertically: Rising Damp.

Into the walls of the building from the ground.

Diffusion:

The movement of a substance from a region of high concentration to a region of low concentration. Latin "diffundere"; to spread out.

Capillary Action:

Moisture cannot jump from one brick to the other, there has to be a continuous pathway for the movement of the moisture being absorbed into a building. This continous pathway is provided by; the mortar beds, which in older properties is usually a readily absorbing sand and lime mixture. The amount of moisture that flows into a building via capillary action is very small.

The Sub Floor:

Underneath the floorboards of a solid walled building; unless it has been covered by concrete, is an area called the sub floor. The sub floor is a void of 18 inches to 4 feet in depth. In some properties the sub floor becomes a basement or cellar. As you can see from the cross sectional view far right: The brickwork; of the sub floor, is below ground level and in direct contact with the ground.

Moisture can readily diffuse laterally across the mortar bed, then rise vertically. Providing a major pathway for moisture absorption; from the ground, into the building.

Air brick ventilation in the Sub Floor:

If you imagine the sub floor area of your property like a small cellar or basement; a void of nothing, 18 inches to 4 feet deep running underneath your house.

Although the retaining walls of the sub floor are in direct contact with the ground. Outside the property just above ground level are air bricks, which allow air to vent into the sub floor. In some terraces the air bricks are also in the party walls so the air can circulate down the entire street.

Purpose of air bricks and a sub floor:

The sub floor allows vented air to circulate underneath your home assisting with the evaporation of moisture absorbed into the walls, before it reaches ground level. It helps keep timbers dry and free of wee beasties eating your floor boards and there is also the accommodation it provides for pipework and cables.

Outlets for absorbed moisture:

The diagram opposite shows the outlets for moisture which has been absorbed from the ground, via the mortar beds of the sub floor retaining wall.

• A: Some of the moisture will evaporate within the sub floor or if present the basement or cellar.
• B: Some will pass into the timbers that are in contact with the wall.
• C: Some will pass into the ground floor plaster. Causing dampness, decorative spoiling and the blistering of paint and or plaster as it evaporates.
• D: Some will evaporate outside.
• E: Some will jump on the floor and do a lap dance.

External ground levels above the existing damp proof course:

Lateral penetrating and accompanying rising damp can also be a problem in properties that have a physical damp course. Problems can occur where there has been a build up of debris, raising of driveways, flower beds, etc above the existing physical damp proof course.

Problems caused will be adjacent to where the damp proof course has been bridged and the construction of the wall will dictate how severe the problem is. A cavity wall has a gap (the cavity) making it more difficult for moisture to pass into the ground floor. Whereas a solid wall has no cavity and moisture will readily pass laterally and vertically into the ground floor of the property.

However you should always check to see if external ground levels are above the damp proof course and also if there is a drain or a leaky down pipe near effected areas.

Rising Damp and Black Mould Growth:

It has been documented that the presence of hygroscopic salts, which are associated with rising damp, kill black mould, implying that if black mould growth is present your growth is caused by condensation, not rising damp.

However this is not always the case as can clearly be seen in the images above of poor Jo's kitchen. Black mould growth can be caused by ground floor moisture absorption. Being found above skirtings in corners and areas of reduced ventilation.

Also the amount of salts contained within the absorbed moisture does vary upon geographical area, water table and building materials.

What is a Damp Proofing Course:

Imagine you are sleeping in a tent without a ground sheet on the ground to stop moisture rising into your sleeping bag. Obviously you will wake up in the morning with a damp sleeping bag. To damp proof your tent against rising damp you simply put a plastic ground sheet on the ground. A modern damp proof course is essentially a piece of plastic which the house is built on top of.

Types of Damp Proofing Course:

A: Physical Damp Proofing Course:

A physical damp proof course is made from plastic or in older properties, they are usually constructed from slate or asphalt. They are inserted into the property when it is being built.

B: Chemical Injection: Damp Proofing Course:

Very popular with big damp proofing companies because the chemicals used are cheep and very little building experience is necessary to undertake the injection.
The main drawback with this type of damp proof course, is that the chemicals used are water based and over time usually 20 years, rising and laterally penetrating damp will dissolve the dpc rendering it ineffective.

C: Gel & Cream Injection: Damp Proofing Course:

The major pathway for moisture absorption from the ground is via the sand or lime and cement mortar between the bricks. Gel injection involves drilling a series of holes in the mortar beds and back filling the hole with a chemical gel.
This type of dpc has become popular with the diy market because of its ease of use, however I have used gels in the past and although they are moderately effective in some properties, I don't advocate their use in properties with a sand and lime mortar bed.

D: Mortar Injection: Damp Proofing Course:

Mortar Injection, is by far the most effective method I have used, one drills holes; as with the gel injection, into the mortar beds, but the holes are back filled with a plasticised mortar, which does not deteriorate over time.

Advocation of unnecessary works:

I do find that customers are often confused about damp issues in their homes and damp proofing companies do tend to dramatize the problem. Causing confusion and fear. I have also found that the advocation of unnecessary works is a problem widely associated with damp proofing companies.

In most cases salesmen; not builders or surveyors, are who recommended; albeit, trusted damp proofing companies will send for your survey. Obviously they are interested in their commission and usually have, limited building knowledge.

"Which" done a very good "Rogue Traders" type of report.

The report scored the bigger damp proofing companies as follows:

• Peter Cox 2/3.
• Rentokil 2/3.
• Kenwood 1/3.
• Lifecote 1/3.
• ProTen 1/3.
• Timberwise 0/3