Dry Rot

What causes Dry Rot?
Timbers affected by moisture over a sustained period of time generally in poorly ventilated areas in dark locations are the most susceptible to Dry Rot attack i.e. sub-floor areas, or where timbers are in contact with damp masonry. Once established Dry Rot can spread rapidly, growing through plaster, brickwork, and masonry, in search of moisture and other timbers to infect.

Why is Dry Rot a problem?
Dry rot (Serpula lacrymans) without doubt is the most serious of fungal decays to affect buildings often causing considerable damage before becoming apparent. Timbers affected by Dry Rot become brittle, and subject cracking, losing their natural strength, which if left untreated or controlled, can lead to structural failure.

How would Dryside rectify the problem?
– Preperation
Preparitory work to be carried out under a separate contract prior to our arrival:-

  • Provide safe working access to the areas of treatment.
  • Rectify cause of moisture, and promote drying out.
  • Remove wall plaster and open up floors etc. to the areas identified in our report and to at least 1.0m beyond the last visable evidence of fungal growth.
  • Cut out affected timbers to approximately 1.0m beyond any signs of fungal growth.
  • Remove all resultant debris and all debris from sub floor areas, oversites,etc.

– Inspection & Surveys
Visual inspection from outside is most important in identifying potential areas and causes of internal timber decay and rot in a building. Of particular importance are defects to roofs, rainwater goods and plumbing drainage plus sub floor ventilation, ground levels and abutting structures. Internally we assess the impact of an external defect by exposing timbers where practical. To assist our diagnosis we use moisture meters, but nothing surpasses the eye of experience.

In occupied properties, our inspection is normally restricted to the readily accessible timbers only, as the fitted floor coverings and furniture limit the extent of our inspection. Ideally we would like all such obstructions to be removed prior to our arrival. With timber rot/decay we identify the cause, the proposed extent and methods of treatment, and other associated building work. If a complete condition and assessment of all timbers within a building is required we recommend that a fully intrusive inspection be considered. This will require the removal of areas of wall plaster, to expose embedded timbers such as lintel above windows, wall plates etc. The opening up of floors adjacent to the external perimeter walls of the property is essential. This type of inspection is available at a cost.

– DrySide Surveys
DrySide carries out inspections to your instructions on properties in relation to basement waterproofing and rising damp, as well as timber defects such as infestations by wood boring beetle (woodworm) and decay such as Wet Rot and Dry Rot. The purpose of our inspection is to provide a report, justification, specification, and quotation for our proposed works and treatments.

The inspection is carried out by specialist qualified staff holding Certified Remedial Treatment Surveyor (CSRT), Certified Surveyor for Structural Waterproofing (CSSW), as recognised by the British Wood Preserving and Damp Proofing Association. Additionally they have passed the examinations of the School of Waterproofing, as well as many manufacturers exams and training courses.

Our senior surveyor alone has over 26 years surveying experience. Dryside offers an honest, balanced and informed opinion which is not restricted to any single manufacturer or pay-related bonus/commission scheme, thereby enabling us to provide our clients with a reliable report, giving justification for our works, indentifying the extent of such work and the proposed specifications, with a realistic quotation in relation to your instructions.

– Treatment
Sterilisation works by DrySide Ltd:
– Thoroughly inspect the exposed area(s) and confirm the cause of the dry rot attack and the extent of the area(s) of the necessary sterilisation. If necessary we will submit a revised quotation for our works.
– Treat the defined areas by one or a combination of the following methods:-
• Thoroughly surface saturate the specified area(s) with dry rot fungicidal fluid.
• Irrigate the masonry with dry rot masonry fungicdal fluid, pressure-injected into 10 to 12mm diameter holes drilled at 200 to 300mm centres and also surface saturate.
• Form a toxic box (Cordon Sanitare) by drilling a double line of 10 to 12 mm diameter holes at 50 to 100mm centres around the perimeter of the dry rot attack and the adjacent unaffected timbers and pressure injecting them followed by surface saturating with dry rot masonry fungicidal fluid.
• Saturate to oversite or hardcore.
• Apply boracol (Probor 20 or similar) high performance timber preservative to the surfaces of immediate surrounding sound timbers remaining in situ.

Client under a separate contract to reinstate as follows:
• Where possible use concrete lintels etc. to local Building Regulations in preference to timber and avoid embedding timbers into and onto the treated surfaces.
• Replace defective timbers with new pretreated pressure impregnated timbers with all cut ends treated with a fungicide and isolated from the masonry and oversite by a suitable DPM. These timbers should have a moisture content of less than 15%.
• Replaster as necessary to our replastering specification.

– Aftercare
The importance of rectifying the source of moisture that caused the dry rot attack is critical to the prevention or recurrence of further or future rot and decay.

Promoting drying out at all times during and following the above specified works until the masonry (this may require the installation of temporary dehumidifiers) has dried out fully. This is likely to take a number of months. During this period we recommend the areas of treatments be carefully monitored until dry.

Why choose Dryside for this project?
The range of Probor products we use are among the most effective and environmental friendly chemicals on the market and we are proud to use them while causing minimal impact to the environment around us.