Olympic Construction » Treat Dry Rot

Treat Dry Rot

The way not to save money on treating dry rot

Two years ago (June 2012) we were instructed to undertake an inspection of fungal decay to the ground floor of a property in Manchester, the inspection was undertaken and we confirmed dry rot Serpula lacrymans, to the rear sub-floor due to a lack of adequate sub-floor ventilation, the instruction to undertake the remedial works was awarded to another contractor, apparently we were too expensive.
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In April this year (2014) we received an instruction requesting we undertake an inspection of the fungal decay to the same property, again dry rot was located to the ground floor timbers and sub-floor walls but this time the infestation was found to be much more wide spread and was also affecting the floor void of the neighbouring property. We informed the client recommending that they contact the contractors who had, undertaken the remedial works only to be informed they had tried, but the contractors were no longer trading, not under the same name or contact numbers anyway.


This time the client gladly awarded the contract to Olympic Construction, following opening up works, it soon became apparent why the dry rot had re-infested the property and spread so fast, the replacement timbers were not treated or protected from moisture, the subfloor voids were found not to be ventilated, and it is unlikely correct cleaning down and treatment works to the masonry were undertaken.
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It appeared the contractor had simply replaced the timbers, so supplying the dry rot with a new source of food and drink, in the photographs below you can see the extent of the mycelium to the sub-floor walls and a dry fruiting body located to the underside of the installed floor panel of the hallway.


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The photograph above showing evidence of two chemical damp proofing systems, but no up rating of the sub-floor ventilation to aid drying of the sub-floor and maintaining the correct level of relative humidity within the floor void. The lower photograph showing the lack of ventilation to the rear elevation.

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The photographs show the required opening up works, completely expose the full extent of the dry rot, all voids and sub-floor walls cleaned down and the ventilation uprated to aid drying of the structure and maintain a constant flow of air, to regulate the relative humidity within the sub-floor voids. After ten days of drying the structure with the aid of heaters and fans installed to aid evaporation and drying of the sub-floor area, reinstalment works were started.
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A damp proof course was installed to all affected walls, where these walls were not land retaining installation being within the first mortar line above the sub-floor level, the wall areas which were land retaining were treated with a cementitious waterproofing slurry to reduce the level of evaporation into the sub-floor to help reduce and control the relative humidity within the floor void.


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The disused fire place base and hearths were removed as they are impossible to damp proof and also reduce the crossflow ventilation within the floor void.

The fugal decay has the ability to spread far beyond the original outbreak, this is why it is paramount you instructure a Property Care Association (PCA) company, who have the correct training and knowledge, to undertake the works effectively. The photograph to the right shows fungal decay affecting the original timber lintels to the heads of the ground floor doorways.

The photographs below show property reinstated to a habitable condition ready for re-decoration.

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Rear lounge showing the floor and wall area original affected by dry rot {First photograph}

The front lounge with new floor and plastered walls. Below the spandrel area located under the new stairs installed, providing a new dry storage area.

All the works undertaken by Olympic Constructions are undertaken by time served and trained tradesman. This allows the works to be covered by a sound guarantee registered with the GPI, which in the unlikely event of Olympic Construction, ceasing to trade like the past contractor, means the works are still insured, giving you the peace of mind.

You can also be sure the works are undertaken in a safe manor as Olympic Construction are one of the few, remedial treatment specialists who are Chas accredited, giving you further peace of mind, your property is in safe hands.

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If you have any questions please call us on 0161 633 9860 and we will be happy to answer any of your questions or make arrangements to undertaken an inspection, of your wall ties to ensure your property is structurally sound.