do you tell the difference between Wet Rot and Dry Rot and why bother?
is not easy to tell the difference between Wet Rot and Dry Rot because there are
many types of Wet Rot and many of their characteristics are similar to those of
Dry Rot. Luckily there is only one Dry Rot, so the easiest way to check for Dry
Rot is to look for the four main identifying features - if none of them is present
the rot is probably a Wet Rot.
here to read the four main features of Dry Rot
need to bother to tell the difference because of one key feature of Dry Rot -
it can travel over dry surfaces, even chemically treated surfaces (if dried out)
to find moist wood to attack. Wet Rots cannot do this, because they need high
levels of moisture to spread within. So, Wet Rots are much, much safer, because
they cannot spread beyond the area of dampness, and that dampness has to be quite
severe, thus making it more obvious and easier to isolate.
Treat Wood for Wet Rot?
speaking the Wet Rot itself does not need treating. Simply remove the source of
moisture and the Wet Rot will die. It cannot spread without water, so in theory
no further action is required. However, this idealist approach ignores the practical
reality. Once you have stopped the water coming in and cut out the physically
weakened wood you will often be left with surrounding timbers that are perfectly
sound, but are significantly damp. These pieces of wood make take many months,
or even years to dry out - this is when they are highly vulnerable to an attack
of Dry Rot. So you must check the remaining timbers for moisture content and if
in doubt treat them with Boron Ultra 12, Boron Paste and Boron Gel, to ensure
that they remain rot free whilst the moisture content falls into the safe zone.
Timber below 18% WME (as measured on a calibrated, good quality 'Damp
Meter' ) cannot be attacked by Dry Rot.
Treat Wood for Dry Rot?
Dry Rot can spread across most surfaces, even behind plaster and skirting boards,
even when the moisture content is below the required level for decay. Any piece
of timber over which strands, mycellium or a fruiting body of dry rot is growing
must be treated with a Boron based product at least 300mm in all directions, to
avoid any of the tiny micro strands of Dry Rot, that precede the main visible
parts of the fungal growth inside the timber, from growing. These micro strands
are tiny, and not visible to the naked eye.
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are the main features of Dry Rot - first identify the rot type in
order to decide the extent of the treatment
Strands - fibres, that look like small plant roots, dirty off-white to
silver grey in colour. Can be confused with some Wet Rots.
Sheets - called Mycelium - looks like a dirty off-white skin, can be tinged
with yellow, occasionally found as billowing cushions of off-white growths. Can
be confused with some Wet Rots.
Mushroom - Fruiting Body - this produces the Spores - rust red in colour,
can spread around onto other surfaces, usually found as a flat body with red spores
in the centre and an off-white rim. Very, very distinctive and quite rare - not
usually confused with any other Rot, but can look a bit like brick dust.
Cubing - wood breaks up into large cubes, but with larger, deeper cracks
along the grain than across the grain. Often confused with Wet Rots, some of which
produce similar cuboidal cracking, but with much smaller true cubes, rather than
the more rectangularDry Rot type.
Rot - large splits, curvature and strands.
the 'cuboidal' type cracking.
on wood - NOT brilliant white.
of a dirty, off white to grey colour.
Dry Rot Sporophore - flat & red rust coloured.
body is very distinctive, usually with red dust everywhere around.
of the many Wet Rots could it be - most commonly misidentified
Coniophora puteana - the 'cellar fungus' - dark brown to black strands
in fern-like patterns, olive brown fruiting body (rare).
Fibroporia vaillantii - white strands in fern like growths, white fruiting
body with pores.
Asterostroma - brilliant white, fine strands, fruiting body has no pores,
mycelium has tiny star structures, visible only under magnification.
rot - brown to black strands of Coniophora.
White strands and Mycellium of Fibroporia
White strands and Mycellium of Fibroporia - both Wet Rots - NOT Dry Rot.
have identified the Rot - now use Boron treatment
best, safest and most pleasant treatment to apply is Boron
Ultra 12, a water based 'biostat' that has no adverse effect on non-wood boring
insects or mammals (like Bats). This Boron Products is applied as two or more
coats by brush or spray and soaks quickly into the timber. It is permanent and,
unlike its main rivals, it has no vapour and no smell. It can only affect wood
rotting fungi and wood boring insects, so Bats (a protected species) are not affected
- their main food, the house fly, does not eat wood and so it never contains any
preservative. Heavily infested areas of timber, and damp patches, should also
have an application of Boron Ultra Gel,
to reduce the risks of future rot and provide extra active ingredient. Permanently
or seasonally damp wood needs injection with Boron
Ultra Paste and the insertion of Boron
Ultra Rods (for example, window frames, garden posts, door frames).
so called 're-entry time', set by the HSE for every Pesticide, is only 1 hour,
or until dry, whichever is the longer. Pet birds and fish are not at risk from
Boron-based preservatives when used as specified, but do NOT apply Permethrin
based alternatives (found in most DIY stores) if you keep any pets, particularly
fish - Permethrin is lethal to fish in minute quantities.
to prevent the spread of Dry Rot - Dry Rot Paint around and over timbers
photograph below shows untreated panels, on the left and treated panels on the
right. The treated panels (in two columns) have been painted with Dry Rot Paint
and show no signs of growth!
you can further reduce the risk of future Dry Rot attack by using this 'No Go
Zone' special emulsion paint. It can be applied behind skirting boards, in window
frame reveals and in joist sockets. The paint, which has been tested by BRE (Building
Research Establishment - Government backed test Authority) prevents Dry Rot from
passing across treated areas. No other treatment can currently offer this feature.
you need any help with any type of Wood Treatment or identification of wood rotting
fungi Property Repair Systems staff will be pleased to give you completely free,
no obligation advice on 01626 336180 .
US FOR HELP TO IDENTIFY YOUR FUNGUS - 01626 336180 - Fungus Help Line
GEL, PASTE, RODS - treatment to kill and prevent insect and Dry Rot attack
ECOBOR ULTRA GEL - Surface Applied Gel for Dry Rot
active clear Boron based Gel ideal for end grain and bearing area treatment of
beams and joists. Apply to surfaces that have been touched by or affected by Dry
Also useful for medium
to heavy active infestations of insect attack and treatment of new timbers for
use in vulnerable areas (e.g. skirting boards).
Ultra Gel in three sizes - 500cc, 1 litre and 2 litres - no odour, easy to brush.
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BORON ULTRA PASTE - Deep Injected Treatment for Dry Rot - no odour
unique Boron based paste using a special blend of technical grade glycols as carriers.
It can be injected into timber, with the advantage of supplying a highly concentrated
mobile preservative which will spread even at low moisture content levels. Simple
to apply with a standard skeleton gun; more effective to use because of the higher
available level of active content, which allows the use of smaller (8mm, rather
than 10mm) and/or fewer drill holes.
Paste in a mastic tube, with an extension adapter nozzle. For injection into wood
to kill dry rot and insects.
available - Timber Paste for dry wood - ideal for fully indoor structural
timbers that are suffering from Death Watch Beetle, House Longhorn Beetle or Termites.
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BORON RODS - Solid Rods for embedding Boron inside holes in wood - prevents and
kills Dry Rot
solid rods of Boron based compound are used to protect timbers which are constantly
or occasionally damp: external joinery, wall plates, embedded beam ends, posts
etc. They can also be used in conjunction with BORON ULTRA Paste, to act as a
long term reservoir (Standard Sizes - 8mm x 24mm and 8mm x 65mm).
of Boron Rods as solid fused sticks of preservative. Example of insertion in a
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DRY ROT PAINT - Special Emulsion Coating - low odour (non Boron)
specially treated preservative biocidal emulsion paint designed to prevent the
surface spread of Dry rot. Ideal for timber and masonry in the treatment of adjacent
areas, to provide visual lasting evidence of treatment. It prevents surface spread
of strands and mycelium.
Site photographs showing how Dry Rot can spread - often in hidden places below
or between floors.
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of Borax Boron based for Dry Rot treatments
Boron has a world-wide safety reputation - 5% products still require no hazard
* Borates have
ultra low toxicity - about the same as Table Salt
Boron based preservative kills only wood rots and wood boring insects - not spiders,
birds or bats
* Boron has
no odour - leaves no smell
Borax does not evaporate - stays in the wood
Boron Ultra 12 has a 1 hour re-entry time - the lowest for any fungicide/insecticide
Borons are non-flammable - they actually act as Flame Retardants
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Support for Dry Rot
PRS products are supported with Method Statements, Specifications and comprehensive
technical support. Please ask for our technical department. Contact us at: 01626 336180 or firstname.lastname@example.org
of Product Guarantee for
offer a printed Certificate of Product Guarantee for individual properties, should
you require one for your Bank, Building Society or house purchaser.
us for details on 01626 336180 .
for Dry Rot Treatment
our Dry Rot Technical Information page for Product Safety Information. The Boron
based product, Boron Ultra 12, used for Dry Rot Treatment diluted in water at
5% or 10% BAE is fully Licensed by the HSE and the 5% version is not required
to carry any hazard warning labels.
to go to Dry Rot Technical Information.
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written by: David
B.A. (Hons.), C.T.I.S., C.R.D.S. Technical Author