The
reason that dry rot is often so devastating is because of its ability to travel
long distances as it searches for more and more timber to remove moisture from
Source: http://www.timberwise.co.uk/ |
I was recently watching a well know property
renovation programme on TV a few weeks ago where the Presenter had identified
what looked to be dry rot on the ground floor of semi-detached three bedroom
residential property. Although, I agree
that what he was looking at did appear to be dry rot, his description included,
‘feeding off concrete’ which is completely inaccurate as well as some of his
terminology being confusing and wide of the mark. TV programmes should be mindful of the
information that they provide, as it is possible, dare I say likely, (just by
the nature of the amount of viewers), that someone will act on what they are
being told which could result in loss/damage. In order to identify if or where dry rot may
be present, it is useful to understand the conditions that dry rot needs to
grow and thrive.
Source: http://livingtherusticlife.com/ |
Dry rot is a living fungus which will continue to grow
by feeding off timber, which it will completely destroy be removing all of its
moisture. Without being too technical,
there are four primary stages in the dry rot lifecycle. The first stage is Spores. The spores are constantly
present in the atmosphere however are only activated in certain conditions,
which include timber and moisture. For
dry rot to thrive it’s ideal environment will include timber with a moisture
content of between 22% and 25% warm humid temperatures of between 240
and 300, poorly ventilated areas and dark concealed spaces. This is
why dry rot will often spread undetected in basement, floor voids, roof voids,
behind plasterboard in timber stud walls and the like. As the spores start to
become more concentrated they develop into small white strands known as Hyphae, which
look a little like small white cob-webs.
These are reasonably easy to identify and a good indication of dry rot.
As the hyphae feeds off the timber it will extract
further moisture from the timber as it continues to grow and become more
concentrated in volume to a point where the hyphae mass develops into the next
stage of the dry rot cycle, know as Mycelium. Visible large white mycelium strands can
travel large distances in search of more timber and as previously stated can
travel across non-timber surfaces in order to find new timber. In
suitable conditions, mycelium will continue to exist and grow at a considerable
rate within a building. Fungi prefers dark and damp areas with little or no air
movement, therefore where these conditions change and threaten the fungus; its
natural response is to create a Fruiting Body (Sporophore), and this is the final
stage of the dry rot lifecycle. Visually
the fruiting body can take a number of forms, however will generally appear in
‘mushroom like’ form. The fruiting body is the fungi's response to a threat to
its survival and its reaction is to throw out spores into the air which can be
transferred to other vulnerable areas within the building, which allows them to
germinate and create a new attack of dry rot, thus restarting the dry rot life
cycle right from the very beginning.
The dry rot lifecycle described
above demonstrates how the fungus can spread so quickly and how much damage
that can be caused if left undetected. It is possible to treat dry rot however
this requires specialist knowledge and something that should not be attempted
‘on the cheap’. If all traces of dry rot
are not dealt with then all that will happen is the fungus will continue to
grow and spread and start to affect any new timber that may have been
installed. The steps below provide an indication of remedial works to deal with
dry rot, however please bear in mind that this is indicative only and
specialist advice should be sought in all situations:
1. Deal with the moisture source
2. Brush down any exposed masonry to remove
visible surface fungal growth
3. Deep-drill masonry at regular centres and
irrigate with fungicidal wall solution
4. Sterilise all exposed masonry surfaces with
fungicidal wall solution
5. Remove all affected timber including a minimum of 1m past the last identifiable location
6. Dispose all affected timber from site
7. Provide new treated and primed timber where
previously removed
8. Spray all new and
adjacent timbers including cut ends with fungicidal spray
9. Re-plaster where required using a cement and
sand render mix
10. Ensure adequate ventilation
is used
Dry Rot is easy to misdiagnose and I would always
recommend that you engage the services of a professional such as a Building
Surveyor for advice and guidance. The short video below provides a good example of dry rot occurring in a residential dwelling and is well worth look. Many thanks to Bryan Hindle who has provided his kind permission for use of the video. Please also take a look at Bryan's excellent article on the following link
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