Rothound Article

“Let Slip The Dogs Of Rot”

Dry rot is apt to strike panic into the heart of homeowners. But before you rip up the floorboards and flood the place with pesticide call in Lottie, the Rothound, to track down the offending fungus.

The best ideas are often the most obvious and so it is with this one. If we can use dogs to herd sheep and hunt down heroin it seems eminently sensible that we can also train them to sniff out infected timbers in all those crevices and corners which building professionals can’t quite reach. But good sense and the building industry are often poles apart. If your foot has just gone through the floor received wisdom recommends that you call in the contractors to quote a price. They’ll make a guess as to the extent of the problem and then proceed to strip away plaster, cut out infected timbers and douse the whole area with pesticides and fungicidal chemicals. All unnecessary, and often ineffective, says Tim Hutton, the no nonsense director of Hutton + Rostron, the company which has pioneered the use of Rothounds in this country. He takes a dim view of the chemical fix and is clearly contemptuous of a dry rot industry which has cast its spores far and wide, spreading perniciously like the dread fungus it was set up to defeat.

Fungal Failures

“Since the end of WWII,” he explains, “modern society has become increasingly susceptible to the idea of an instant ‘spray on’ solution to any problem. Remedial timber treatment became very profitable and even the most cynical could survive by repeatedly forming new companies that failed as their treatments failed”. This he knows from bitter experience. In 1975 the company moved into a National Trust owned country house and discovered that it was rotten to the core. A remedial expert was called in and later walked out with £30,000 in his back pocket, but the problem persisted, prompting Tim and his team to conduct extensive research into the nature of the problem.

“We came to the conclusion that timber decay is not caused by a deficiency of pesticides but by building failures. From this we developed an ‘environmental policy’ which is based on three steps: non-destructive inspection of the building to identify the extent of the problem, remedial building techniques to sort it out, and a maintenance regime to prevent recurrence”.

Lottie Vs Serpula lacrymans

Non-destructive inspection is where Lottie comes in. Set her loose in a building and she’ll scamper from room to room in double quick time sniffing the air for the offending invader, tracking down outbreaks which are still invisible to the human eye and identifying well-established colonies secreted behind panels, plaster work or floor boards.

There are many advantages to using dogs like Lottie, says Tim. “She can get into inaccessible places, search 20-50 rooms in an hour and discriminate between dry rot and other fungi instantly. She can detect the scent from several metres and indicate the extent of the infestation. But most importantly, she can work in furnished buildings in a non-destructive way”.

image002So effective is the technique that Lottie and her chums have been used by the National Trust and English Heritage to scan historic buildings for signs of attack. They were also brought in to a post-fire Windsor Castle to assess the extent of the infestation prior to restoration. But while Lottie has socialised with the top dogs it’s not just grand country houses and royal residences which call in the hounds. Rothounds, says Tim, can be used to survey properties prior to purchase, to survey properties with known dry rot problems to determine the extent of the problem, and to check out properties after remedial work to make sure nothing has been missed. Given the obvious benefits, not mention Britain’s undoubted enthusiasm for all things canine, it seems strange that Hutton + Rostron are the only company in the country which uses Rothounds. “The idea began in Scandinavia,” says Tim, “but no one else seems to have taken it up here. The treatment of dry rot has certainly improved but the industry has a lot invested in chemical techniques”.

Environmental Control

With this in mind it’s worth pointing out that the Hounds are only one stage in the rescue of an infested building.” Hutton + Rostron’s environmental control policy is based on understanding how the dry rot fungus functions,” says Tim. “Once the problem has been identified by Lottie we then proceed to the next phase”.

Serpula lacrymans

image003Here a detailed understanding of the offending organism is crucial. Serpula lacrymans may look like some insidious invader from outer space but like any other biological entity it will only thrive in certain conditions. It needs a moisture content of 20-30% to flourish and dies out when the heat rises above 25 degrees centigrade. Remove the favourable conditions and you remove the problem. “Every area of decay is associated with a building defect overflowing gutters, persistent leaks and so on – and these need to be corrected. Pumping masses of water-based fungicide into the walls is not the answer, you need to isolate the source and work from there.” Once the remedial work has been carried out it’s then a case of monitoring the building to make sure there is no recurrence of the problem. For this Hutton + Rostron have invented a special low cost sensor, the Curator, which automatically monitors the moisture levels and sends back reading to a central computer.

“Timber decay,” Tim concludes, “cannot be eradicated by event the most Draconian pesticide treatments. But the conditions in which destructive organisms can flourish can easily be avoided with a little thought and scientific understanding”. That and Lottie’s highly evolved sense of smell.

The company provide a report detailing all of the areas of active dry rot in the building and give brief advice on what is causing the problem. They provide a 30 year guarantee for their recommendations and specifications.

Because the system is more accurate in identifying the extent and causes of the problem the costs, Hutton + Rostron claim, are often less, in the long run than techniques based on the use of chemical treatments. It is also less invasive and a greener way to proceed.

Michael O’Flynn, 11 Jul 2001 Feature, web site.


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