What is Dry Rot and How to Fix it and Prevent it
Dry rot is the scourge of anyone who works with wood. It can very quickly and very easily get into wood and start to decay it. In fact, such is the level of damage it causes, it is more of a hazard than other forms of destruction – for example, dry rot destroys around 20 billion board feet of timber each year in the United States – this is far more than is damaged annually by fire.
Obviously, the biggest danger of dry rot is to commercial lumber yards or timber producers. However, even if you are not a commercial user of wood, you can still take steps to prevent the wood in your home from being attacked by dry rot.
Even if you do notice a small amount of dry rot in the wood of your home, it’s not too late. You need to act quickly, however, as dry rot can quickly spread. Acting quickly can be the difference between spending hundreds of dollars and spending thousands.
Use this guide below to better understand what precisely dry rot is, and how you can prevent it from taking control of the wood in your home.
WHAT IS DRY ROT?
Dry Rot
is a type of wood decay caused by a fungus. It’s also known as brown rot in some parts of the country. Dry rot feeds on organic matter – particularly wood – and once it gets into the wood, it continues to spread until it has colonized an extremely large area.
What makes dry rot so damaging is that the fungus effectively ‘eats’ the wood, breaking down the cellulose and the hemicellulose, both of which are critical to the strength of the wood. Once the dry rot has broken down these compounds, wood no longer has the same resilience as it initially had, and is therefore of no use in construction. If the wood is already part of a structure, it can fundamentally damage the weight-bearing ability, thereby leading to collapse.
Dry rot – despite the name – only affects timber that is damp. The name is actually a misnomer because at one time it was thought that dry rot did not require moisture in order to flourish.
However, while it does not require a large amount of moisture, there must be some present in order for it to grow.
In order for dry rot to survive, the wood needs to have a moisture content above:
Once dry rot gets into the wood, the wood is left weakened and brittle and often has a ‘crumbly’ or ‘blocky’ appearance.
For wood that is outside, you need to cover or store it in a dry environment.
For wood that is part of your home, you need to ensure that it is properly coated, and to monitor for signs of dampness.
Dry rot does not appear every time wood gets wet, although wood that is consistently wet provides the ideal grounds for dry rot spores to take hold.
HOW DOES DRY ROT SPREAD?
Like most other forms of fungus, dry rot spreads through spores traveling through the air. In this respect, you can think of dry rot as being like a type of mold (with all the implications that has for prevention and treatment). The fungus produces spores, which spread through the air, carried on the wind until they land on a surface. If the surface is wood and has the requisite level of moisture, then the spores will germinate.
In order for germination to happen, the wood needs to fulfill one of the following criteria:
- The wood was not properly kiln-dried before being used. This still leaves it with moisture levels in excess of 20 percent.
- The wood is in a humid location (either in terms of the climate, or the part of the home).
- The wood has been in contact with large amounts of water, such as from a flood or a burst pipe.
In addition to moisture, dry rot spores also have an optimal temperature, preferring wood that is between 71 and 77 degrees. This means that dry rot tends to flourish in warm parts of the country, or more readily during the spring and summer months. Dry rot does not spread easily when the temperatures are either side of this window. Dry rot also needs oxygen to flourish.
If dry rot is left to spread unchecked it will weaken wood to the point that it will disintegrate, making it totally unusable and structurally unsound. Once a piece of timber has become infected with dry rot, it cannot be treated to return its structural soundness. Instead, the timber must either be destroyed or – in some cases – the infected part can be excised. If your basement has had water damage or if it has flooded, there is likely dry rot.
HOW TO PREVENT DRY ROT
The best course of action when it comes to dry rot is to not get it in the first place. Prevention is far better than cure. Luckily, there are lots of things you can do to inhibit dry rot from taking hold of your wood.
Below is a list of common steps for preventing dry rot:
SIDING
You should ensure that all of the wood in the walls of your home is covered with a properly sealed siding. A skilled siding installer will ensure that the wood is free from moisture by creating a watertight seal.
PAINTING
Any wood that is designed for outdoor use should be primed and painted on all six sides before being used. Any gaps in the paint can lead to dry rot getting in.
ROOFING
A roof provides two key roles in keeping your home free from dry rot – firstly by providing a waterproof seal on top of your home. You should check the roof for leaks at regular intervals. The second way is by redirecting water away from your house – make sure your gutters take water at least six feet away from your home.
PLUMBING
The most common cause of dry rot is leaking from plumbing pipes. If you find any leaks inside or outside your home, get them repaired as soon as possible. In particular, you should check regularly around precious items of furniture for leaks.
VENTILATION
Proper ventilation is a major tool against dry rot. From simple things like keeping your windows open to installing proper ventilation fans in kitchens and bathrooms – this will prevent moisture from building up. Buying and using a dehumidifier will also help with this process.
DECK
Because decks consist of large amounts of outdoor wood, they are extremely susceptible to dry rot. You need to make sure that your deck is properly sealed. You also need to make sure that water runs off easily, either with a slight slope or with gaps between the slats.
LANDSCAPING
Many homeowners set their sprinklers up without due care for wood. Ensure that sprinkler systems don’t spray onto your home and you will help to prevent moisture levels from getting too high.
TREATMENT
FOR DRY ROT
If the worst happens, and you do get dry rot in your home, all is not lost. At this stage, you will almost certainly need a professional carpenter. They will be able to advise on the extent of the spread, as well as be able to excise the wood that is infected.
There are three main courses of action when it comes to dry rot in wood:
1
Epoxy Treatments
Once the dry rot wood has been cut out, epoxy is used to fill in the channels that have been damaged. Not only does this strengthen the wood’s structure, but it also kills the remaining dry rot that may be lingering in the wood.
2
Commercial Antifreeze
The harsh chemicals in antifreeze kill the wood and prevent any further growth. This is usually the best solution if the dry rot has not spread too far.
3
Copper Compounds
Copper compounds are used as a form of treatment when splicing new wood and cutting out a damaged portion. The surface of the wood is saturated with a copper compound solution to prevent dry rot from further taking hold.
IF YOU HAVE DRY ROT...
As mentioned above, you will need to get professional help. Although it may seem likely an unnecessary cost, especially if the solution is simply to cut out the infected wood, dealing with dry rot properly can totally prevent it from spreading further, saving you thousands of dollars. Think of hiring a professional carpenter as an investment.
ULTIMATELY,
dry rot is a common and damaging blight on wood throughout the United States. It is estimated that 10 percent of wood sales in the US comes from the need to replace rotten wood. This shows the extent of the damage that dry rot can cause. Luckily, the steps to prevent dry rot are fairly common and not too labor-intensive.
It’s far easier and cheaper to prevent than to cure dry rot, so taking the time to paint and treat your wood is by far the best use of your time. Otherwise, you’ll need professional help, and that’s where things start to get expensive.