How to Identify Dry Rot and Wet Rot and Treat it

Identification of your rot is the first part of this important process, these picture help you identify and diagnose different forms of dry rot and wet rot so you can treat it effectively. It is intended to give you an easy insight into the types of rot and treatment, but we also have further information on the difference between wet and dry rot and the processes and products you can use to treat dry rot.

See our other project page for more in-depth information on diagnosing and treating rot. It is a worthy point to note that dry rot can seriously damage your property so if you suspect that it is present it is well worth getting professional advice. In respect to expert advice, Property Repair Systems are on hand to offer specialist information, call them on 01626 872 650, no charge and no obligations!

Pictures of Dry Rot and Wet Rot

You can use the images below to help you identify the type of rot that you have in your home. The images depict the most common forms of both dry rot and wet rot and how they most commonly appear.

Dry Rot

The strands that you can see when dry rot starts growing look like roots. They are white, off white or even silver grey. When these strands dry out they turn brittle, where wet rot would stay flexible.

Wet Rot

Coniophora Puteana – known as the ‘cellar fungus’. The strands are dark – grey, brown or black. They form fern-shaped patterns. When they are dry they remain flexible. Occasionally they will form an olive-brown fruiting body, but this is very rare.

Fibroporia vaillantii – also known a cellar fungus, this looks similar to the fungus above but it has bright white strands, and have white fruiting bodies and spores.

Asterostroma – this has very fine brilliant white strands. The fruiting body has tiny star-like structures, but these are only visible using magnification.

Sheets or Mycelium

Dry Rot

As you can see from the picture, this is a dirty off-white sheet, which forms a kind of skin on the surface of the affected timber. It can sometimes be yellowish or slightly lilac coloured, but it is not a bright white – a brilliant white skin would indicate wet rot rather than dry rot.

Wet Rot

This is more of a skin or coating, and the wet rot is a bright brilliant white.

Fruiting Body or Sporophore

Dry Rot

This is the mature version of the fungus and this is the part that produces spores. Spores are the method that the dry rot uses to spread throughout the timber. They are rather like seeds in that they land on timber and look for the right conditions to start growing.

The fruiting body of Dry Rot is usually rusty red and/or ochre yellow with an off white outer edge. There could be touches of lilac or silver grey here too. You will often be able to see the red spores in the middle. It is usually a flat body which looks a bit like a tree mushroom you might see in woodland.

Wet Rot

These are the tiny fruiting bodies of wet rot they are small mushroom like fungi that are off white.

Dusting or Spores

Dry Rot

The spores are rusty red and will be cast about by the mature fruit to land on all available surfaces. By blanketing the area in the way the fungi is hoping that the spores will find an area where they can flourish and grow. This is rare to find because the rot is usually discovered and treated before the fungus can get to this stage.

Wet Rot

This dusting is not from spores, but from the activity of wood-boring weevils which only affect timber which is already rotting. It looks like sawdust, because that is basically what it is.

Wood Cracking or Cubing

Dry Rot

The wood forms deep cracks along the grain (the length of the timber), and then smaller cracks form across the grain to form a cube-like structure. ‘cubes’. The wood can also shrink and curve inwards.

Wet Rot

Wet rot does display similar symptoms but the dry rot tends to form bigger and more irregular cubes, where the wet rot forms smaller and more regular cracking.

Dry Rot Treatments

Boron Powders and Solutions

The best, safest and most pleasant treatment to apply is a product called Boron Ultra 12 which you can buy from Property Repair Systems as a powder or ready to use.

This Borate is a water-based ‘biostat’ and this means it has no ill-effect on non wood–boring insects or on mammals.

This Borate is easily applied as two coats either by brush or spray, and it quickly soaks into masonry and timber. It is permanent and, unlike its main rivals, it has no vapour or smell.

It is formulated so that it can only affect wood rotting fungi and wood boring insects. It will not affect bats (a protected species) or their main food, the common house fly, which does not eat wood and so never gets contaminated with any preservative.

Boron Gel and Paste Treatments

Damp patches and heavily infested areas of timber, should have an application of Boron Ultra Gel (pictured above) as well, to reduce the risks of future rot and provide an extra active ingredient.

Permanently damp wood also needs injection with Boron Ultra Paste (above) together with the inserting Boron Ultra Rods (below). These can be placed into any vulnerable timber such as window frames, garden posts, or door frames.

The so called ‘re–entry time’ for all pesticide treatments is only 1 hour, or until dry, whichever is the longer. This guidance is set by the HSE (Health and Safety Executive – a Government body concerned with safe working practices).

Pets, birds and fish are not at risk from Boron–based preservatives, but do NOT apply alternative products which contain Permethrin (which can be found in most DIY stores) if you keep any pets, particularly fish – Permethrin is lethal to fish, even in minute quantities.

Additional Precautions Against Dry Rot

Dry Rot Paint

Paint Dry Rot Paint onto unaffected areas around the affected area that you are going to treat, to prevent the spread of rot. Read more about the dry rot barrier paint on Property Repair Systems Website.

The picture above shows panels treated with the paint on the right and untreated panels on the left. The two columns of treated panels have been painted with PRS Dry Rot Paint and show no signs of mould or fungal growth!

So, you can further reduce the risk of future Dry Rot attack by using the ‘No Go Zone’ Rot Barrier Paint by Property Repair Systems. This special emulsion paint can be applied behind skirting boards, into window frame reveals and in timber joist sockets. The paint, which has been tested by BRE (Building Research Establishment – a Government backed Test Authority) prevents Dry Rot from passing across treated areas. We know of no other treatment that can currently offer this feature.

If you need any help with any type of Wood Treatment or identification of wood rotting fungi including Boron treatments, the Property Repair Systems staff will be pleased to give you completely free, no obligation advice – 01626 872 650