What You Should Expect From a Damp Survey

Comment

Property Remedial Articles - Olympic Construction

When purchasing or selling a property following the valuation inspection being completed by the RICS surveyor, you may find a recommendation to have a further damp and timber survey undertaken by a ‘Specialist damp and timber surveyor/ contractor who is a member of the PCA Property Care Association, the reason the PCA is recommended is simply because RICS acknowledge members of the PCA will be both qualified and accountable.

So back to what you should expect as a minimum from a damp survey undertaken correctly.     

Firstly the company contact details, these should be clear and include :-

  • Company name
  • Address
  • Telephone numbers
  • Website
  • Email address
  • Vat number
  • Company registration number
  • Name and qualifications of the surveyor who undertook the survey, not a company sign off.

Full details of both the property and your address.

Full details of your instruction, check and ensure these are correct.

A full detailed description of the property, not just a generic description.

Any survey to a property should start with a full walk around the property to establish the orientation of the site.

A close inspection to the roof and its covering a defective roof will result in water ingress, this is a form of dampness and should be noted.

Inspection to the chimneystacks and flashings, the chimneystack is one of the most exposed areas of the property and is also one of the most neglected when it comes to maintenance. Water ingress into any part of the structure will be detrimental resulting in dampness and decay but water entering the chimney structure can easley result in what is termed salt dampness ‘The movement of hygroscopic organic salts into the plaster surface’ these result in staining, dampness and delamination of the applied plaster. Water ingress into the chimney structure also presents a risk to the bearing timbers of the roof structure being affected by fungal decay.

DSCN2049
DSCN1964

Photographs showing defective chimney and salt dampness

The rainwater systems A defective rainwater system results in a high risk of penetrating dampness affecting the internal elevations of the property and frost damage to the external brickwork.

Brickwork and pointing defects are another cause of penetrating dampness into properties and with more properties having cavity wall insulation this can result in an expensive issue.

The pointing should be closely inspected as it may not always appear what it seems, works undertaken correctly to BS 8221-2:2000 :  Code of practice for cleaning and surface repair of buildings. Surface repair of natural stones, brick and terracotta, will last for years, but works undertaken using cheap and unsafe methods, like working from a ladder will result in what we term ‘Scratch pointing’ being undertake, where pointing materials are applied over the original pointing, without sufficient material being removed to allow sufficient bonding to the brickwork and the material drying to fast, resulting in cracking and falling away.

DSCN2840

A Defective gutter noted on the external inspection to a property
.

Where this type of pointing application is used the works will only have a short working life, being affected by sunlight, frost and rain resulting in failure and the works having to be undertaken again to prevent water ingress into the structure, resulting in penetrating dampness.

Walls constructed of stone require special attention, especially where these have been pointed with an OPC mortar, traditionally the original mortar base within the property would have been lime base, were this has been over pointed with OPC cement, which is much harder and less vapour permeable. This material and finish will cause damage to the adjoining stonework, since it is not able to transmit moisture as readily as the stonework, resulting sulphate formation causing deterioration to the stonework immediately adjacent to the pointing, allowing water into the structure and the pointing to be dislodged by the effects of water and frost.

Defects affecting the structure such as corroding steel, resulting in a direct path for water ingress into the structure.

DSCN7184

Stone work damaged by the use of OPC mortar
.
DSCN2768

Opening of the mortar joints above a window due to corroding steel
.
DSCN2326

Evidence of scratch pointing to a property in Chadderton only four years old.
.
The inspection should take note of the external ground levels, as high ground levels can result in bridging of the installed damp proof level, resulting in moisture tracking across into the floor timbers, as well as the added issue of the sub-floor ventilation being blocked or obstructed.
DSCN2777
DSCN2778

In the photographs above, note the raised external path level due to the block paving contractor having installed the paving over the original path. This resulted in a bridging of the installed DPC level and obstruction to the installed sub-floor ventilation, in this case the rear elevation was affected by rising dampness and the floor timbers were affected by wet rot.

The internal survey

The internal inspection should make note of visual defects, these being staining to the walls surface, bridging of the DPC level by plaster, smaller skirtingboards having been installed, the wall surfaces having been over plastered and areas which cannot be inspected due to the installation of tiles and dry linings. I have found both these system used in the past to hide the effects of dampness, the inspection should also include the upstairs walls, including chimneybreasts, dampness can manifest in various forms and at different levels, the inspection you requested was a damp inspection, not simply and inspection of the damp proof course, if the inspection is limited to the damp proof course only, chances are they are trying to sell you a damp proof course and are not really interested in providing you with the damp report you requested.

Bridging of the damp proof course level by the plaster having been taken down to the solid floor, this area being located under the stairs.

Bridging of the damp proof course level by the plaster having been taken down to the solid floor, this area being located under the stairs.

In this case the damp proof course was bridged by plaster, the original skirtingboards having been replaced with smaller skirtingboards and the lower exposed brickwork being replastered with light weight gypsum based plaster.

In this case the damp proof course was bridged by plaster, the original skirtingboards having been replaced with smaller skirtingboards and the lower exposed brickwork being replastered with light weight gypsum based plaster.

Where possible the defects should be clearly but simply explained to prevent confusion, there should also be a clear remedial works specification provided within the report, not just a recommendation for a damp proof course.

An inspection to the upper areas of the wall should be undertaken, to identify areas affected by penetrating dampness and condensation, noting the location of radiators which if installed in the incorrect locations, will move moisture loaded air towards the cooler external elevations, resulting in condensation and high surface moisture readings, this is not rising dampness, the recommendation should be to relocate the radiator.

Salt dampness or dampness appearing on chimneybreasts is becoming more of an issue, this being due to a combination of lack of maintenance, changes in the use of the chimney structure and the lack of adequate ventilation within properties, this should be identified and if there is an issue this should be noted and the correct remedial specification put forward.

The report should close with a conclusion of the surveyors findings and recommendations, which should include any limitations preventing inspection as well as any health and safety issues which need to be address, so you can make a judgment in relation to the issues noted. The report should be a source of information not simply just an estimate for damp proofing works.

Finally the report should be signed and the name and qualifications of the surveyor clearly visible.

pdf-icon    Download a Report example of what you should expect.