All About Wet Rot

Posted on Posted in General

Wet rot, as implied by its name, is caused when wood is subjected to high levels of moisture. Water may come up from the ground caused by simple things like inadequate gutters or a pipe leak. In some cases, it could be caused by a structural issue within a building that may cause the roof to leak or water to enter through the walls. It is a fungus that attacks wood or lumber to extract food. The fungus does this in order to maintain its growth by producing a generation of spores, which will naturally spread and attack more wood. It destroys the basic elements of wood resulting to the weakening of the lumber. If left unchecked, the structural integrity of the lumber can be severely affected.

Wet rot looks nasty and smells terrible. It is often seen in basements, bathrooms and kitchens but may infest other rooms in your house as well. It may also affect your deck, balcony or breezeway; anything in your house that has lumber may be infested with it as well as damp, poorly ventilated environments. Just like dry rot, wet rot can affect both old and new buildings.

In order to grow, wet rot requires a regular source of moisture that typically comes from gutters, defective plumbing or downpipes. The presence of water and wood together allow wet rot spores to germinate and begin its life cycle. Left on its own, the fungus removes the strength lumber has, making the lumber structurally unsound.

There are two types of wet rot – the brown wet rot and the white wet rot. Both are destructive to lumber but have different effects depending on the type of wood they are attacking. The brown wet rot is more commonly known as cellar fungus. It is brown with delicate brown threads sprouting from the rotting wood. When this type of rot is present, the wood will shrink and crack. It becomes brittle and will take on a darker color, not unlike a dry rot attack. Since brown wet rot causes wood to shrink, it creates cube-like cracks less deep than the cube-like cracks present in dry rot.

brown wet rot

White wet rot has a light brown sheet-like appearance. There are light brown threads sprouting from the rotting wood. As the wood breaks down because of the presence of white wet rot, it exhibits a coarse, fibrous appearance with a lightening color.

white wet rot

These are the telltale signs that wet rot is present:

  • There is a largely black localized fungus growing on timber.
  • Wood feels soft and spongy when touched even through a coat of paint.
  • When dry, lumber will easily crack and crumble into fine particles and it may also be susceptible to shrinkage.
  • There is a musty odor.
  • There is presence of damaged or flaky paint, which increases the risk of wet rot.
  • If paint is undamaged it is possible that the lumber underneath may be rotting from the back. You can do a quick test by inserting a thin bladed knife into the wood. The blade should stop after a very short distance. If it goes in up to the handle, it is almost a certainty that there is rot behind the paint.

It is important to know what type of rot problem you have because the treatment for dry rot and wet rot are vastly different. There are cases when it is difficult to identify the difference between the two. Though dry rot is more serious, wet rot should not be taken lightly as wet rot causes lumber to lose its integrity. If wet rot is present in areas such as decks, balconies, floors, railings, and stairs, your family’s safety and yours may be at risk. The good thing about wet rot is unlike dry rot, wet rot fungus does not spread along the wood and will confine itself to the wet areas only.

It is also worthwhile to note that most insurance companies exclude loss caused by wet rot. If you think that you have a wet rot problem, make sure to resolve it as soon as possible before the damage it may create can cost you much, much more.

If wet rot telltale signs are present, it is best to call in a professional to find out what the best solution is. The majority of wood in homes tends to be in enclosed and hard to reach areas such as under floorboards, behind skirting boards or door frames. Since these areas are often unseen, it is common that the spread of rot has already progressed widely even before the homeowner knows that there was a problem in the first place. Professionals would know how to thoroughly inspect your home for wet rot including those hard to reach areas.

In the Los Angeles area, Westside Company is THE professional to call. Westside Company has decades of experience in providing solutions to your problem especially if present in your deck, balcony, railings or stairs. Call Westside Company at 310 994 4626 or e-mail us at for a free consultation. We guarantee that we can give you the best customer experience. We provide repair and maintenance services for the greater Los Angeles area including Norwalk, Lynwood, Gardena, and Hawthorne.

After repair, here are some handy tips to help you keep your home free from wet rot:

  • Eliminate all sources of damp or moisture that lumber is exposed to.
  • Ensure that all external lumber frames are treated, sealed, and adequately painted to protect the wood from the frontal ingress of water.
  • Check your house regularly for any damp walls and address the problem. If there is damp, it is wise to seek professional advice, as this may be a sign of an even bigger issue.
  • Make sure that soil and debris is cleared away from around wood frames.
  • Check the roof space for ingress of water.
  • Check all areas for leaks from water supply or drain.
  • Consider waterproofing decks, balconies, basements, stairways and other places where moisture is difficult to eliminate. Waterproofing can certainly give excellent protection for all your home’s lumber.