Identifying Damp In your home

There are several types of damp and it is important that the cause is correctly diagnosed. TDT will come to your home and establish the cause and extent of the damage caused by damp. We have an extensive range of damp proofing products available to resolve the damp problem in your property.


The object of providing a damp proof course in the walls of a building is to prevent moisture being drawn by capillary action from the ground with which the structure is in contact.  Building materials are generally porous therefore they have the ability to soak up water in a similar action to that of a wick.

Moisture carried into the wall by a rising damp process will allow the wall to become wet and thus be susceptible to damage by frost.  The moisture will also pass into the joinery fittings such as skirtings, door frames and windows, causing conditions in which a variety of wood rotting fungi flourish.  In addition, all soils contain natural salts, these salts combine with the moisture and are drawn up through the wall structures.  During the natural drying out process the salt bearing moisture in the wall is carried to the surface, whereupon the moisture evaporates leaving behind deposits of these natural salts within and upon the surface of the wall.  The salt breaks down the internal plasterwork, mortar joints and external rendering, causing them to become hygroscopic and thus capable of absorbing moisture from the atmosphere and consequently compounding the damp problem.



It is important that the cause of a damp problem is correctly diagnosed.

There are basically four main sources and causes of dampness in buildings:

Lateral penetrating damp (usually from below external ground levels)


Vertical penetrating damp (from above external ground levels)

Rising damp



This usually occurs on the external walls where the external ground level is higher than the internal floor level and consequently the moisture bearing soil allows water to pass through the wall.

It can also occur where internal floor levels vary and where the floor level of an adjacent property is higher.

Other causes of lateral penetrating damp are: abutting garden walls, paths, flower beds or fuel storage and less easily recognised are situations where the floor screed is porous or has bridged an existing damp proof course.

Obstructions causing lateral penetrating damp should be removed otherwise the walls must be waterproofed by applying an impermeable surface.

We offer a separate structural waterproofing, or tanking, service.



This manifests itself as surface moisture and is often prevalent on hard impervious surfaces such as gloss paint, tiles and vinyl wall coverings etc.  Poorly ventilated corners will also show indications of condensation.

The amount of water vapour that air can contain is limited and when this capacity is attained the air is described as saturated, at this point condensation will form on surfaces within the building.

The saturation point will vary with the temperature and the amount of water to be vaporized is dependent upon many factors.  In simplified terms, “dry” background heat and ventilation will prevent or reduce condensation.  Oil and gas fires are not recommended as they tend to produce moisture.

TIMBER DECAY TREATMENT LIMITED can offer advice and systems which can control these situations.



This is often caused by defects such as porous window cills, string courses or masonry.  Roof defects, leaking, blocked or undersized gutters and downpipes will also contribute to this commonly encountered problem.  Occasionally cavity materials will form the necessary bridge across a wall to allow water penetrating on the external skin to adversely affect the internal wall surface.

Regular building maintenance is very important.  In some circumstances the application of external wall treatments can assist the eradication of such problems.  Again we can provide this as a separate service.



This will often be apparent in a visual form by a roughly horizontal “tide mark” on a wall.  Above this line the plasterwork will normally be quite sound but below it the decorations are usually stained and plasterwork will become efflorescent.  Rising damp rarely occurs higher than one metre above external ground levels.

If hygroscopic salts have accumulated the surface will appear damp, mould growth and efflorescence may also occur.

Rising damp usually affects older houses built before the Public Health Act of 1875 when the provision of a damp proof course became obligatory and houses where the original material used for the damp proof course has broken down or become bridged.



During the considerable number of years that Timber Decay Treatment Ltd has been introducing damp proof courses into buildings we have seen a variety of theories and methods rise and wane in popularity.  We have also carried out experiments and tests of our own during this time and continue this practice.

The methods we use and recommend will depend upon the circumstances prevailing on site.  Wall construction, siting and environmental considerations will all be appraised.

Holes are drilled in a horizontal plane, generally from both sides of the walls and from one side of thinner internal or party walls, and damp proofing materials introduced into the walls.  The materials used disperse through the wall to form the barrier which resists moisture rising by capillarity.

The systems are suitable for preventing rising damp I most walls which have no damp proof course or where the existing damp proof course has broken down.

The damp proofing injection materials we use are covered by certificates issued by the British Board of Agrément and BSI.  They are manufactured under strict quality control and covered by the Government Health & Safety Executive.



 We are an established Company who have been operating since 1967.  We have a first class reputation gained during this period.  Our work is recommended and accepted by Local Authorities, Architects, Surveyors, Building Societies and other specifying bodies.



Timber Decay Treatment Limited have experienced and qualified surveyors, one of whom will visit your property to carry out a full and detailed inspection, report on their findings and recommend suitable eradication measures.


WARRANTIES (where applicable) 

Timber Decay Treatment Limited’s own 10 year Warranties can be underwritten and protected by a separate and independent Guarantee.  Double protection is thereby assured.  Both documents are transferable to any subsequent purchaser of your property.  This underwriting scheme is administered by the Guarantee Protection Trust Ltd (GPT).



Timber Decay Treatment Limited are members of the PROPERTY CARE ASSOCIATION.  Work undertaken by us is carried out in accordance with a strict code of practice.  You can be assured that the work will be property executed and the Building Societies and Local Authorities will accept our standards. 

It should be noted that this membership is normally the minimum qualification required of treatment Companies by the above bodies for mortgage and grant purposes.

CALL TDT PRESERVATION – 01761 416 728 


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