A NEW DEVICE FROM MCGILL CONSULTANCY
EU Patent No EP(UK)1512969
Dry Rot Detection
Some New Technology (How
does this work)
Its often said that the trouble with dry rot is that you can’t find it until someone sticks their foot through the floor. It is well known that the dry rot fungus Serpula lacrymans commonly grows in dark damp unventilated places where it is difficult for surveyors to find.
These days are gone now thanks to some recent developments that mean we can now find dry rot quite easily.
Not only can we find it before the piano sinks into the floor: we can find it before it does any damage at all to structural timbers.
This can have a revolutionary impact on the way we go about searching for dry rot. Not only can we find it before it does any damage, but we can carry out detailed inspections for dry rot without doing any damage ourselves.
The benefits are too many to number; but here are a few:-
· No need for disruptive surveys.
· Cornices can be saved
· Ornamental woodwork can be saved
· “At Risk” areas can be tested
· The full extent of spread of dry rot can be mapped out
· Growth can be monitored
· We can establish if it’s alive or dead
· We can implement environmental control methods and watch them work
· We can tell if our eradication has been successful.
This new patented technology has been developed as a result of a greater understanding of the fundamental nature of the growth and development of the fungus and the way in which it breaks down wood. It is based on the biochemical principles that underpin the mechanism of action of the decomposition of wood. That’s enough science but how does it work in practice?
The procedures involve placing special
sensors that react to dry rot in areas that are
affected by dry rot or are at risk of becoming
affected by dry rot and examining them from time
to time to see if they have undergone a colour
change. It’s really that simple. In fact
it’s simple reliable neat and inexpensive.
Here are a few photos to illustrate the technology
1. Sensor located in the area where dry
rot is suspected
2. Sensor removed after 4 days
3.Sensor removed completely- note the colour
change from blue to yellow confirming the
presence of Dry Rot
4. Floor lifted to reveal
Dry Rot below - as indicated by sensor
Two types of sensor are available. Single purpose dry rot sensor and dual-purpose moisture sensor and dry rot sensor. The single purpose sensor is useful if a surveyor is suspicious of a location within a building and feels that more information is needed.
This can happen in a situation for example where there is a stain in plasterwork that seems to have arisen from an ingress of moisture. Single purpose sensors placed adjacent to structural timbers that might be at risk from dry rot can tell if decay has started or is about to start. Appropriate intervention can then be implemented. Similarly in the event of a typical domestic flood from a washing machine or toilet overflow, the affected area can be tested to ensure that dry rot does not develop as the area dries out.
Dual- purpose sensor are appropriate when it is necessary to collect detailed information about the spread of moisture
within a building and to map out the areas affected by dry rot or that might become affected by dry rot. Such information is required when carrying out a detailed survey of a building. Or when an outbreak of dry rot has been discovered and it is necessary to map out the full extent of the spread of dry rot without the normal disruption of lifting floors and removing plasterwork.
Who can use this
An important advantage in the application of both types of sensor is that they can be fitted and examined by anyone. No specialised equipment is necessary. The single purpose sensors are simply fitted then removed for examination. The dual-purpose sensors are designed to be used in conjunction with an electrical moisture meter for determining the spread of moisture, then removed for examination.
After examination sensors that have not reacted can be re-fitted for future examination. Sensors that have reacted may be replaced for future examination. The can if desired for part of a long-term monitoring procedure.
This might be done where it was desirable to deal with the dry rot using environmental control technology for example in a historic building.
Here are a few examples of how the sensors can be used in survey work
1 A surveyor carrying out a routine inspection notices a damp stained area
That he thinks might give rise to dry rot.
He tells his client he wants to check it out and does so by fitting some single purpose sensors. He gets either a yes there
is dry rot or no there is not.
2 A surveyor finds dry rot in a roof void but can't see how far it has spread into the room below. He can either fit some
single purpose sensors and will get a yes there is dry rot until the point where the dry rot stops. Or he can fit dual purpose sensors and map out the spread of moisture that will tell him the whole at risk area, then remove the sensors and establish how far the dry rot has spread within that at risk area. He has then established how far he has to go with his treatment in order to stop the dry rot from spreading further.
3 An area previously treated for dry rot becomes wet as a result of a flood from a pipe or similar. Dual purpose sensors
can be fitted in the affected area allowing the moisture to be monitored until it fully dries out. As the area dries out the sensors can be checked to ensure that there is no dry rot re-development . Once dry there is no longer a risk, the sensors can be removed.
4 An outbreak of dry rot has spread behind some ornamental panelling in a historic building. To treat the outbreak by conventional methods would involve damage to the panelling. Dual purpose sensors can be fitted within and around the affected area and the activity of the fungus monitored.
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