Dry Rot In A House

How bad is dry rot in a house?

Your home is most likely one of your greatest investments. To protect your investment, it is important to be able to spot small problems before they become major expenses. Dry rot is one of those problems.

Dry rot is caused by a fungus that feeds on wood and weakens it. Wood becomes cracked and brittle and eventually breaks down. Dry rot is particularly a problem in older homes where wood may not have been treated to prevent rot damage.

In nature, wood rot is a vital decomposition process, turning fallen logs into nutritious soil. But few things send homeowners into a panic as quickly as discovering it their homes, because wood rot can lead to a number of structural problems, including deteriorated support posts and beams, rotted floor and ceiling joists, and destroyed roof decking. The cost to repair the damage—or, in other words, replace the rotted wood—can run in the tens of thousands of dollars.

Because wood is the most prevalent building material, it’s essential to understand what causes wood rot, how to prevent it, and what to do if you discover it—discover being the operative word, as wood rot is often hidden from view beneath flooring, wallboard, and siding. Read on for the must-know info.

Your home is often your pride and joy. You put a lot of work into making sure it is maintained, beautiful, and works for your needs. Over time, issues will arise that need attention, and it’s up to you as a homeowner to identify these possible problems and know how to respond to them.

One issue that can happen to homes, especially as they age, is dry rot. Because so much of your home is made from wood, it can be prone to dry rot, which will, in turn, affect the structural integrity and strength of the property if serious enough. Knowing how to identify dry rot and understanding the steps you need to take to remedy the situation as quickly as possible will help ensure that your home stays strong.

Here we’ll take a look at what dry rot is, how to identify it, and what to do about it.

At Hitch Property Constructions, we offer timber repairs work from simple timber repair to almost new structures, renovations, and extensions.

Dry Rot Is Dangerous To The Structure Of Your Home

Dry rot is a widespread problem for homeowners in the Pacific Northwest. Often dry rot is hard to notice or detect because it tends to occur in the hidden inner structures of your home: beneath floorboards, inside crawl spaces, and behind walls. However, dry rot also occurs in visible places, such as your roof, areas of window or door framing exposed to rain, skylights, and on counters and inside cupboards. Because it is spawned in wet places, the dry rot fungus will often take hold in bathroom or kitchen areas and damp basements.

Dry Rot In A House

What Is Dry Rot?

Dry rot is a fungus that feeds on moist or damp wood, which is overly abundant in the rainy Northwest. It may be ironic that the dry rot fungus thrives on wet wood, but the term ‘dry rot’ actually refers to the condition of wood after it has been infested and deteriorated by the fungus. First identified on extensively used ships in England, dry rot describes wood that is in a state of disrepair that is brittle, cracked, crumbly, and virtually useless for its intended function. The disintegration of wood caused by the dry rot fungus destroys the strength, durability, firmness, and vigour of wood—which are all qualities you want to have in the wooden structures and surfaces of your home. Got Rot?

Stop Dry Rot Before It Spreads!

How dangerous is dry rot? Dry rot is caused by a harmful fungus that does not merely infect one area of your home, then die off. Often referred to as ‘building cancer,’ the dry rot fungus continuously spreads throughout all available sources of moist or damp wood that your home may contain. Once it has taken hold, it progressively deteriorates and weakens the wooden structures and surfaces of your home, rendering them increasingly less sturdy and stable. In effect, the dry rot fungus eats away at the integrity of your home, compromising its capacity to provide a safe or effective living environment.

If you are asking yourself, “How does dry rot affect my home?” you should know that dry rot is essentially wood decay and represents a progressive deterioration of the wooden structures and surfaces in your home that can cause severe and irreversible damages. Therefore, it is essential to have it removed and the affected wood structures repaired before it becomes too far gone of a problem. Just like a cavity in your tooth, the longer you wait to have home dry rot removal and home dry rot repair work, the worse the decay will become, and the more compromised the integrity of your home will be.

Due to the very harmful and accelerating impacts of dry rot, it’s best to have your home inspected today so that if you do have a problem, a contractor can repair it before it’s too late.

Signs & Symptoms Of Dry Rot: How To Detect It Before It’s Too Late

As a fungus, dry rot first appears as a mass of tiny red spores or brownish spore dust that spreads out across a wood surface. As it develops, dry rot fungus turns into a branching mass of white strands that cling to the wood. Dry rot can also appear as a thick mass of cotton or sprawling cobwebs. It is common for wood thoroughly invaded by the dry rot fungus to be covered with mushroom growths. This typically represents the end stage of dry rot in which the wood has become utterly dilapidated.

Wood that has any strange looking growths on it, appears unusually stained, dark, or discoloured, or has a musty odour that smells like fungus or soil is likely infected with the dry rot fungus. Dry rot can also cause wood not to function properly. Wood that is unusually loose or has shrunk, frequently seen in door frames or window ledges, may indicate dry rot. Floors that appear warped and concave or “give” when walked upon are sure signs of underlying dry rot in your floorboards.

Dry Rot Health Hazards

While dry rot presents a significant threat to the structural integrity and safety of your home, there are also considerable health hazards. How dangerous is dry rot to your health? First, suppose you have dry rot in the living spaces of your home. In that case, this may indicate an environment that is overly humid and which may cause you to be prone to respiratory problems or exacerbate existing asthma. While most folks don’t have allergic reactions to the fungus that causes dry rot, a minority of people do. Also, dry rot can jeopardize the functionality of your home and cause-related problems that are bad for your health.

What Causes Wet Rot and Dry Rot

Finding the source of your rot problem is key to making sure it is dealt with effectively. The main cause of rot is moisture in timbers. Wood destroying fungus feed off this moisture and as a result visible signs of dry rot or wet rot damage appear on the affected timber. Wet and dry rot spores will only develop and take hold of timbers if the environmental conditions are correct.

In order to prevent rot, you must fix ventilation issues and damp problems, such as rising damp, penetrating damp and condensation as they are the main causes of excessive moisture within a property.

What Causes Dry Rot?

Dry rot is a wood-destroying fungus that grows from moisture found in timber. For Dry Rot to start germinating, there needs to be excessive water i.e.

Dry rot spores are always present in the atmosphere. Once they land on timber, they will germinate and produce hyphae (fine strands of fungal growth), if under the correct environmental conditions. The impact of dry rot in your property can cause severe loss of timber strength and threaten the structural integrity of a building if not addressed.

How Does Dry Rot Develop?

Once the hyphae strands are formed, they join together to create a mass called Mycelium which can vary in colour from grey to pure white, and these strands grow into and across the damp wood. It can also grow over materials such as plaster, mortars, bricks etc… in it searches more timber.

When the growth in advanced, a fruiting body (Sporophore) may develop. This fruiting body takes the form of a “fleshy pancake”, the surface of which is orange/ochre-coloured.

Check out our range of timber repairs Melbourne at Hitch Property Constructions. 

Signs of Dry Rot

Dry rot can be problematic to any property, so it is essential that you identify signs of dry rot before further damage is done. If you notice the following, then it could indicate a dry rot problem:

  • Distinct mushroom smell
  • White fungal growth with yellow and lilac tinges
  • Deep cracks appear within the wood
  • Both soft and hardwood timbers can be damaged

What Causes Wet Rot?

Wet rot is a form of fungus that affects very damp timber and can ultimately result in timber to decay. Thriving from a moisture content between 30% – 60%, wet rot can appear from a number a reason where excessive moisture is able to penetrate the timber, from a leak in the roof, an incorrectly fitted plumbing or a burst pipe.

How Does Wet Rot Develop?

Wet rot requires the correct environmental conditions, the correct moisture levels and exposure to timber. Wet rot will use moisture in the damp timber as a source of food but will be limited to that one area unless the moisture source grows. Wet rot is limited to timber and can not spread through masonry and will stop once the moisture source has been eliminated.

Signs of Wet Rot

Wet rot in timber can cause issues with the structure of a property, making it essential that you identify signs of wet rot before further damage is done. If you notice the following you may have a wet rot problem:

  • Distortion, discolouration, softness and cracking
  • Loss of strength to the timber
  • Visible fungal growth – this may sometimes occur
  • Smell – there may be a damp, musty smell

Where Is My Home at Risk?

Because wood rot occurs in damp areas that do not dry out, it often goes undetected until a remodelling project exposes it. The following areas are the most likely spots for wood rot to get a foothold.


Today’s windows are designed to prevent leaks, but all it takes is a small gap that’s not adequately sealed with caulk for the rain to seep through and saturate the wood in the wall beneath the window. Because the wood is not exposed to air or sunlight, it remains damp—providing optimal conditions for fungi growth. Older wooden windows are at even greater risk, as water tends to pool on the horizontal sills, seeping through cracks in the paint.

Exterior doors

Like windows, cracks and gaps between a door and the siding (or threshold) permit water to enter, making them prime spots for wood rot. The rot is often found when homeowners decide to install a new door. Once the old door frame is removed, the rot is visible in the wood framing.

Outdoor decks

Horizontal decking boards and stair treads can also hold water. While many treated decking boards are water-resistant, they’re not 100 per cent waterproof, and over time, they can rot. The bottoms of painted balusters are a prime spot for rotting; they’re typically built from untreated pine, and then painted to resist the elements. Water becomes trapped under the bottom of the baluster and doesn’t dry out, giving fungi a chance to grow.


High humidity and moisture are prevalent in basements because the concrete walls are surrounded by moist soil. Humidity levels can be so high in leaky basements that water vapour can form on the surface of walls and wooden ceiling joists. Once wood rot gets a foothold here, it can spread unnoticed until it creates structural damage.

Wet rooms

Any room with a plumbed water fixture, such as a kitchen, laundry room, bathroom, or utility room (with a water heater) is at risk. Leaks around water supply lines and drain pipes keep the area wet and provide an optimal environment for wood-rot fungi to thrive.

Damaged roofing

Missing or damaged shingles can permit water to seep in, and over time, it can lead to wood rot in the roof decking and in the lumber used to frame the attic.

We have a wide range of Melbourne timber repairs for your home renovations. Check out Hitch Property Constructions.

How Should I Look for Wood Rot?

Checking your home for signs of wood rot should be an annual mission, and a good time to do it is during your pre-winter weatherproofing tasks. You’ll need a long-handle screwdriver and a good flashlight.

  • If your home has wood siding, examine the siding around and beneath the windows for signs of swelling or discolouration. Paint can hide wood rot, so poke the siding with the tip of the screwdriver—the wood should be firm and hard. If the screwdriver sinks into the wood, you’ve got a wood rot problem.
  • Using a strong flashlight, check the attic for discoloured wood. If you find any, perform the screwdriver test. Wood should never be soft. Prime spots in the attic for wood rot are on the underside of the roof decking, in the joints where the wood members connect at the peak of the roof, and at the edges of the attic where the rafters slope down to form the eaves.
  • Check the wood members in a basement or crawl space, using the flashlight to detect discolouration around the perimeter wood plate that sits directly on the top of the concrete basement wall (sill plate). Probe any discoloured areas with the screwdriver.
  • Examine walls and floors beneath sinks, around tubs and showers, and the water heater for signs of water leaks or discolouration. If you find mould growing, the wood floor plates behind the wall are at risk of wood rot. The only sure way to find out is to remove a section of the wallboard and check the wood behind.

Fixing dry rot should be a two-step process. You want to fix the area that is damaged and replace the compromised wood, plus you want to take preventative measures to ensure the moisture no longer seeps into the wood, therefore, stopping dry rot from happening again. This means eliminating or at least reducing excess moisture.

Often it can be best to call in a professional to assess the damage and then make the necessary repairs. This ensures the job is done correctly, the house keeps its structural integrity, and further issues with moisture are remedied.

When it comes to dry rot, it should be taken as a serious issue. Leaving it unresolved will allow the dry rot to progress and in serious cases, affect the structural integrity of your home, making it unsafe to live in.

If there is considerable runoff near the house, consider installing a rain barrel to collect water or connecting your downspout to a drain tile that can move water a safe distance from your home.

Most importantly, treat dry rot as soon as it is discovered! Untreated, dry rot can cause major damage to your home.

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