Wood is a fundamental building material used in everything from framing to flooring. However, wood rot can lead to significant damage, often costing thousands of dollars in repairs. If not addressed, wood rot weakens the structure of your home and can also invite pests like termites.
This article will help you understand what causes wood rot, how to prevent it, and what to do if you encounter it in your home.
Let’s get straight to the point.
Wood rot is caused by moisture that enables fungi to grow and decay wood, often leading to costly repairs and structural damage. It occurs in three main forms: brown rot (dry rot), white rot, and soft rot, each affecting the wood differently.
Common areas prone to wood rot include windows, doors, decks, basements, bathrooms, kitchens, and roofs where moisture accumulates. Prevention methods include sealing gaps, maintaining gutters, using treated wood, installing ventilation, and fixing leaks promptly.
If wood rot is discovered, minor damage can be repaired with wood filler, while extensive damage requires wood replacement. Treat wood with borate to prevent rot, and always address moisture issues to avoid further decay. Act quickly when signs of rot appear to avoid larger problems, and consult a professional for extensive repairs.
What Is Wood Rot?
Wood rot occurs when moisture accumulates in or on wood, allowing fungi to grow. These fungi break down the wood’s fibres, leading to decay. Wood rot comes in different forms and can be hidden behind floors, walls, or roofs, making it difficult to spot until significant damage is done.
Wood Rot Prevention
Preventing wood rot is easier and cheaper than repairing it. Here are some practical steps to take:
1. Seal Gaps And Cracks
Check around windows and doors regularly for cracks and gaps, and seal them with caulk to prevent water from seeping in.
2. Maintain Gutters And Downspouts
Keep your gutters clean to ensure proper drainage and prevent water from pooling near your home’s foundation or siding.
3. Use Treated Wood
When building outdoor structures like decks or fences, use pressure-treated wood resistant to moisture and fungi.
4. Install Ventilation
Bathrooms, kitchens, and basements should have adequate ventilation to prevent moisture buildup. Installing exhaust fans or a dehumidifier can help keep these areas dry.
5. Fix Leaks Immediately
Any sign of a leak around pipes, roofs, or windows should be addressed immediately. Even small leaks can cause moisture to accumulate and lead to wood rot.
6. Paint And Stain Regularly
Apply paint or wood stain to outdoor wood surfaces to create a barrier against moisture. Reapply as the manufacturer recommends, usually every 2-3 years, to maintain protection.
7. Elevate Wood Structures
Avoid direct ground contact for structures like decks, fences, or sheds. Elevating wood slightly off the ground with concrete or metal supports can reduce moisture exposure and increase durability.
8. Use Water-Repellent Sealers
For added protection on outdoor wood, apply water-repellent sealers designed to penetrate deeply into the wood. This helps prevent moisture absorption and reduces the risk of fungal growth.
9. Ensure Proper Drainage Around the Property
Grade the land around your home so water flows away from the foundation. Poor drainage can lead to moisture seeping into the wood components of your home’s structure, increasing the risk of rot.
10. Inspect Roof Flashing
Roof flashing around chimneys, skylights, and vents should be checked for cracks or gaps that allow water to seep into the wood framing. Properly sealed flashing prevents water from reaching structural wood elements.
11. Keep Shrubs and Trees Trimmed Back
Vegetation that grows too close to wooden structures or siding can trap moisture, leading to rot. Maintain space between plants and wood to ensure airflow and reduce moisture retention.
Repairing Wood Rot
Depending on the extent of the damage, there are ways to fix wood rot.
1. Small Areas Of Damage
For minor rot that does not affect the structural integrity of the wood, you can remove the damaged section and use wood filler to restore the surface. After that, seal the area to prevent future rot.
2. Extensive Damage
If the rot has affected a large area or compromised a load-bearing part of the wood, you must replace the damaged wood. In severe cases, it’s best to consult a professional to ensure the repair is done correctly.
3. Treating Wood To Prevent Rot
One way to prevent rot is by treating wood with borate. Borate is a fungicide applied to wood during construction or after rot is discovered. It helps prevent the growth of fungi and can stop existing rot from spreading.
For wood that has already begun to rot, applying a fungicide such as borax after eliminating the moisture source can halt the decay’s progress.
4. Use Epoxy For Medium Damage
Consider using epoxy wood fillers when rot damage is moderate and does not affect the wood’s structural integrity. These can strengthen and fill gaps in wood, creating a durable, weather-resistant surface.
5. Strengthen Joints With Metal Brackets
Consider reinforcing with metal brackets for load-bearing wood components if only part of the wood is rotted. This provides additional support without needing a complete replacement.
6. Address The Source Of Rot Before Repairs
Before you repair, find and eliminate the moisture source to prevent future rot in the same area. Whether sealing a crack, fixing a leak, or improving ventilation, addressing the cause ensures the repair will last.
Types Of Wood Rot
There are three main types of wood rot, each with different characteristics:
1. Brown Rot (Dry Rot)
Brown rot is often called “dry rot” because the affected wood appears dry and brittle. It is caused by fungi that consume the wood’s cellulose, causing it to shrink, crack, and turn dark. Brown rot can spread quickly and cause severe structural damage if left unchecked.
2. White Rot
White rot attacks the lignin in wood, leaving behind the lighter cellulose. It makes the wood feel spongy and soft, often turning it yellowish or white. While it does not spread as quickly as brown rot, it can still cause significant damage.
3. Soft Rot
Soft rot is slower to develop than brown and white rot. However, it can thrive in a broader range of temperatures, from 0°C to 110°F (43°C). Soft rot typically appears in outdoor wood that remains wet for long periods, such as logs or trees, but it can also affect buildings if conditions allow.
Common Areas In Your Home Prone To Wood Rot And Moisture Damage
Wood rot typically starts in areas where moisture is present but does not dry out. These are the most common places where you might find rot in your home:
1. Windows
Although modern windows are designed to be watertight, cracks around the frame can let water seep in, causing the wood to rot inside the walls. Older windows with wooden sills are especially prone to water pooling, which can lead to rot.
2. Doors
Gaps around doors, especially at the threshold or between the door and the siding, provide entry points for water. Homeowners often discover wood rot when replacing doors, especially when removing old metal doors.
3. Decks And Stair Treads
Horizontal surfaces like decks and stairs are especially prone to water pooling. Even treated wood is not immune to moisture; untreated or poorly maintained decking can rot over time.
4. Basements
Due to the surrounding wet soil, basements tend to have high moisture levels. This moisture can condense walls and joists, creating ideal conditions for developing wood rot.
5. Bathrooms And Kitchens
Any area with plumbing, such as bathrooms and kitchens, is at risk of wood rot. Leaks around water pipes and fixtures create moisture that can cause fungi to grow and damage the wood.
6. Roofs
Damaged or missing shingles allow water to seep into the attic and rot the roof decking and structural beams. Over time, this can lead to extensive and costly damage.
Causes Of Wood Rot
Wood rot occurs when three main factors are present: moisture, fungi, and time. While wood can handle occasional moisture, consistent exposure to water allows fungi to thrive. These fungi break down the wood fibres, causing decay.
Moisture is often the result of leaks, poor drainage, or high humidity. If these issues are not addressed, wood rot will continue to spread.
Identifying Wood Rot
Identifying wood rot can be tricky because it is often hidden. However, there are some signs to look for:
- Softness: If the wood feels soft or mushy to the touch, this is a clear sign of rot.
- Discolouration: Wood that has turned dark, yellow, or white is likely rotting.
- Cracks: Wood affected by brown rot will often crack into small, cube-like pieces.
- Odour: Rotting wood sometimes emits a musty, earthy smell.
You must act quickly to prevent further damage if you notice these signs.
When Should Wood Be Replaced?
In some cases, the damage caused by rot is too extensive to repair, and the wood must be replaced. This is typically the case when more than 20% of the wood is affected or if the wood is part of a load-bearing structure.
If you are unsure whether to repair or replace rotting wood, consult a professional. They can assess the damage and recommend the best course of action.
Conclusion
Wood rot is a serious problem that can weaken your home’s structure and lead to costly repairs if not addressed. The key to avoiding extensive damage is to act quickly when you notice the signs of rot. You can keep your home safe and structurally sound by preventing moisture buildup and regularly inspecting vulnerable areas.
If you suspect wood rot in your home, consider getting an inspection from a professional to assess the damage and recommend a solution. Prevention is always better than cure, so take steps now to protect your home from future rot.
FAQs About Wood Rot
How Do I Know If My Wood Is Rotten?
Look for signs of wood damage around the home. This comes in many forms: discolouration, shrunken size, cracks, and splintering. As rotting progresses, it breaks down the cellulose in the wood. This causes the wood to become soft and dark in colour and gets smaller as the cellulose is consumed.
Can Rotting Wood Be Saved?
When you come across rotted wood in your old house projects, instead of replacing the damaged wood, you can also repair it with specialty epoxy penetrants (also called consolidants) and fillers to make repairs. This is faster, and the fixed wood is stronger than the original.
What Are The First Signs Of Dry Rot?
Signs of dry rot include:
- Damaged or decaying timber.
- Damp or musty smell.
- Deep cracks in the timber grain.
- Brittle timber or timber that crumbles in your hand.
- Concentrated patches of orange-brown spore dust.
- Grey strands on timber.
- Fruiting bodies that look like large mushrooms.
What Kills Wood Rot?
Borate treatment prevents wood rot in new wood and kills fungus and rot-causing organisms. Treatments made of ethylene glycol kill wood-consuming fungi and insects drawn to damaged and weakened wood. Both borate and glycol treatments soak into dry wood because they are water-soluble.
How Do You Fix Wet Rotted Wood?
However, wet rot can be stopped by treating the timber with a fungicide. The treatment involves applying a fungicide during the drying-out period. The fungicide can be supplied in concentrate form (usually for professionals for use over large areas) or as a ready-to-use product.