Preservation treatments

Rising dampness

Rising dampness can occur for a variety of reasons and is often misdiagnosed and this can lead to the application of an inappropriate solution.

The worst case of misdiagnosis that we have witnessed was in a school for autistic children where, during the preceding 20 years, four different contractors had each installed a new silicone injection damp proof course, together with requisite salt retardant re-plastering, in the belief that the previous damp proof course had failed.

Following another ‘failure’ we were employed to undertake a thorough investigation and established that the walls, in fact, were dry and that the source of moisture emanated from the sub floor environment.

Photo One was taken from a sub floor inspection that was undertaken in order to accurately determine the reason for an alleged failed damp proof course. The slate damp proof course had been exposed to lateral dampness from raised external ground levels via a cavity wall that was blocked with accumulated mortar residue and this had resulted in the de-lamination and consequential failure of the slate. The timber wallplate, embedded into the wall above the slate was also found to be decayed by wet rot fungi as a result of the same defect.

At Remcure Ltd we pride ourselves on undertaking accurate diagnostic inspections that lead to the specification of appropriate remedial damp proofing treatments.

Fungal decay of wood

Wood is an inherently durable material which is resistant to most biological degradation, provided it remains dry. However, prolonged wetting leads to a risk of decay by wood rotting fungi, though susceptibility varies according to the wood species. Many types of fungi can be found in buildings, only some of which cause wood rot.

In consideration of the reasons for outbreaks of fungal decay there is a requirement for five conditions to be met. Four of these are always present.

1. A source of food - timber
2. A source of infection - fungal spores
3. Oxygen
4. Temperature - temperate climate

The fifth ingredient is moisture.

The majority of older buildings contain timbers built into the external fabric at the time of construction, i.e. lintels, wallplates, joist ends, rafter feet and fixing blocks.

It is a fact that the majority of dry rot outbreaks are linked with faulty rainwater goods and it is essential that the source/s of moisture responsible for such outbreaks are remedied as part of any treatment specification.

It is therefore easy to comprehend that maintenance of building facades, rainwater goods, roofing, valleys, flashing details, sub floor ventilation and external ground levels are extremely important if fungal decay is to be avoided.

Dry and wet rot

Dry rot is the most virulent organism of fungal decay of wood and occurs as a consequence of timber or organic matter being exposed to prolonged, low level dampness in a poorly ventilated space, often following an escape of water into a sub floor void.

The fungal strands have the ability to penetrate masonry, concrete and the like and the remedial treatments to eradicate an outbreak can be extensive.

There are many species of wet rot, (some commonly confused with dry rot), that can lead to total decay of infected timbers.

The major difference in treatment specifications between these and dry rot is that, once the source of moisture has been addressed, there is a need to renew the decayed sections only rather than resort to widespread plaster removal and cutting back of otherwise sound timbers.

We are pleased to confirm that our surveyor has attained the CSRT qualification awarded by the Property Care Association, (formerly the BWPDA), in order to demonstrate our ability to accurately identify the species involved then provide technical treatment regimes to be used in a safe manner.

As approved users of Wykamol and Triton Chemicals products we have access to industry leading treatment products that enable us to proffer long term guarantees. If requested we are also able to provide an insured guarantee via Construction Guarantee Services Ltd.

For further information please click on the following links:

www.wykamol.com
www.triton-chemicals.co.uk

Wood boring beetle infestations

Whilst there are numerous species of this ilk, commonly we encounter three main species:

• Common furniture beetle (Anobium punctatum)
• Death Watch beetle (Xestobium rufovillosum)
• Woodboring weevils (Euophryum confine & Pentartrum huttoni)
• Each of these has unique characteristics and accurate identification is required in order to provide appropriate remedial woodworm treatments.