Rotten Timber

How do you fix rotten timber?

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    Rotted wood is a common problem in older homes. Rotted wood can happen indoors and outdoors due to moisture or age. Most rotted wood is near pipes, attics, basements, door jams, decks, and fences. Thankfully, rotted wood can be repaired instead of replaced.

    Moisture allows fungi to feed on rotting wood. Fungi damage goes beyond rotten wood. Any lasting rotted wood repair must treat both rotted and unrotted wood.

    Moisture-exposed wood rots over time. Untreated mould can be unsightly and cause home damage. Rot is easy to fix. You can make your home look brand new by patching rotted wood with epoxy, wood filler, or another piece of wood.

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

    What You'll Need

    Rotten Timber


    • Putty knife
    • Rasp or utility knife
    • Wood chisel


    • Paintbrush and paint to match
    • Sanding block or 100 grit paper
    • Polyester or Epoxy filler
    • Wood hardener


    Evaluate the Damage and Diagnose the Problem

    Conduct an inspection of the area where you believe there may be rotted wood, measuring the extent of the damage and estimating how much work will be required to repair it. If the area of rotted wood is contained and does not account for more than fifty percent of the product, you should be able to repair the rot without the assistance of a professional or replace it.

    Find out what led to the rot in the wood so that you can take steps to prevent it from happening again and permanently. Check for leaks, open spaces where weather elements and moist air can affect the area, and bad drainage areas. If the area in question is outdoors, you should also consider checking your gutters and areas with poor drainage.

    Clear the Rotted Wood 

    Remove the rotten wood carefully using the rasp or chisel you have available. To accomplish this, you'll need a light touch and just the right amount of pressure. Be sure to treat any areas that look like they might be weak around the rot in the wood. After it has been removed, the area should be cleaned of any debris.

    Apply a Wood Hardener 

    A wood hardener can be purchased at the hardware or home improvement store in your neighbourhood. The hardener is a resin that will penetrate the wood, thereby creating a seal, and will assist in preventing moisture from entering the wood. Apply the wood hardener to the exposed area with a paintbrush of appropriate size, and then wait for it to dry completely.

    Apply Filler 

    The most effective agent for filling the wood is wood putty or epoxy. Putty should be applied to the spaces that need to be filled with the help of a putty knife. Before the putty dries, you need to make sure that it is smoothed out and any excess putty is quickly removed. Give the putty at least a full day, but preferably overnight, to dry completely.

    Sand It Down

    After the putty has had enough time to dry, sand it down with a sanding block or some sandpaper so that it is the same level of roughness as the surrounding wood. Dust and splinters should be removed by blowing them away or removing them with a dry rag, respectively.


    If you intend to paint the area after it has been repaired, it is possible that you will first need to prime the area with a primer. This will depend on the area. Apply the primer with a paintbrush and make sure to follow the instructions on the bottle before allowing it to dry completely.


    Paint the patchwork. Depending on the results, apply one to three coats. Dry and voila! Okay!

    Epoxy has two hardening components. It can be shaped by hand but hardens to hold its shape. It bonds to wood and is weatherproof. When dry, sand, prime, and paint the filler. It takes stain like pine. Create fake grain lines with a utility knife before staining. The wood-like illusion hides patchwork.

    How to Restore Rotted Timber

    STEP 1: Remove the rot

    To locate areas that have been damaged, you can use a screwdriver or a narrow chisel (rotten spots are noticeably softer). It is not safe to assume that it is sound because the surface appears to be in good condition because rot can frequently occur under paint. Use a chisel to remove large chunks by gouging or scraping them away.

    STEP 2: Soak the timber

    Use some kind of preservative on the wood. Repeat the process until the wood can no longer absorb any more (usually three to four applications). Remove any excess with a wipe. TIP: If you want to improve the area's penetration, drill some holes into it. Using a nozzle squeeze bottle makes it much simpler to fill in holes.

    STEP 3: Apply the epoxy filler

    Epoxy filler should be used to help rebuild any missing areas. To anchor the epoxy in deep holes, drive screws partially into the timber before applying it. Before the filler sets, use a putty knife to smooth it out, and then dip the putty knife in epoxy solvent or lacquer thinner to prevent the filler from sticking to the knife.

    Rebuilding wood

    Before applying the epoxy, make sure the wood is protected from the rain for at least a week. Roughen the surface of the wood using coarse sandpaper or a wire brush, as epoxy adheres most successfully to bare, unfinished wood. Because ultraviolet light breaks down epoxy, any exterior repairs should be painted within three days.

    Epoxy liquid should be soaked into wood that has been severely damaged. To get it to penetrate the surface thoroughly, you can use a brush and a squeeze bottle. It is recommended to apply multiple coats while the previous one is still tacky.

    Removing the Rotted Area

    Claw out rotted wood out with a hammer. 

    To dig out loose rot, you should use a claw hammer. The claw of the hammer should be positioned at the base of the rot. While you are bringing the clawback closer to you, apply pressure. Take away as much as you can without damaging the healthy wood without disturbing it.

    • Don't force the wood to remove it. Only get rid of the soft, rotting wood.

    Use a router with a V-shaped bit to remove any remaining rotten wood. 

    Keep the router held so that the bit is one eight of an inch (3.2 mm) away from the back edge of the piece of wood. You can remove any rot that the hammer couldn't reach by grinding it away with short strokes that go back and forth. Turn the wood into a powder until you have wood that is healthy and solid. The router will have a more difficult time cutting through wood with a higher hardness.

    • If rot is left inside the wood, there is a chance that it can start rotting again.

    Sand off paint and surface rot. 

    Because many patching solutions will not adhere to the existing paint, the paint will first need to be removed. To get rid of any residue that is left on the surface of the wood, you can use either a paint scraper or sandpaper with a coarse grit, somewhere around 60. While moving around in a circle, maintain a consistent amount of pressure on the object you are working on.

    • Dirt, rust, or primer should also be removed from the wood's surface before moving on.

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

    Apply 4-6 coats of a wood restorer to the area. 

    Make use of the brush that was provided in order to apply the restorer all over the affected area. After applying each coat of restorer, wait two minutes for it to dry so that it can penetrate the wood. After allowing the restorer to completely dry for two hours, you can continue working on it.

    • Wear rubber gloves when working with the restorer to prevent it from coming into contact with your skin.

    Making a Wood Patch

    Utilizing a Japanese hand saw, make a cut in the wood that is both smooth and straight.

    Position the teeth of the saw along the line that you want to cut so that they are closest to the handle of the saw. In order to make the cut, you will need to apply pressure to the saw and then pull it down at a 45-degree angle. Continue making cuts until you can pull the piece of wood out by hand.

    • Mark the line you want to cut with a pencil, so you stay straight.

    Trim a piece of cedar to the size of the hole you're filling. 

    Use a saw to cut the patch to the correct size. Make sure that the wood fits snugly in the rotted out area. If it's too loose, it will not fit flush with the existing wood.

    • Cedar is commonly used as a patch since it is known for being rot-resistant.

    Dampen the exposed wood with a wet rag. 

    The glue you'll be using activates with moisture. Use a damp cloth to rub the exposed wood where you'll be placing the patch as well as the patch. It should feel slightly wet to the touch.

    Apply polyurethane glue to the wood and place the patch. 

    Squeeze the glue from the container directly onto the wood. Spread it, so it covers the entire exposed area. Press the patch against the wood tightly so the glue can begin to set.

    • Polyurethane glue foams and expands before it hardens so it can fill in any small gaps.
    • Do not touch the uncured glue with your bare hands or tools. It will be extremely difficult to remove.

    Drill two screws into each side of the patch to hold it in place. 

    Use screws long enough to reach the baseboards. Place one on each side of the patch to hold it in place while the glue sets.

    Sand any excess glue off the patch after 6 hours.

    It takes 6 hours for the polyurethane glue to completely dry and set. Use fine-grit sandpaper on the hardened glue to wear it down level with the wood.

    Using Wood Filler for Patching

    Pour a 3 in (7.6 cm) diameter circle of wood filler on a non-porous surface. 

    Placing the wood filler on a piece of plastic or glass will prevent it from sticking to the material or becoming entangled in it. Make sure the circle is approximately half an inch (13 mm) thick so that you have enough to mix at the beginning.

    Squeeze the tube of hardener with the cap still on. 

    The hardening agent will separate in the tube, so firmly squeeze it with your fingers to ensure it is mixed together before you open it.

    Put a 3 in (7.6 cm) strip of the hardener on the filler and mix. 

    Use a putty knife to stir the filler and the hardener together for about 2 minutes. When it's thoroughly mixed, it should have a light red colour.

    • The wood filler has a working time of 10 minutes, so only use small amounts at a time.
    • Keep the mixture spread thin so it will have a longer working time.

    Apply the filler to the wood with a putty knife with firm pressure. 

    Beyond the problem areas in the wood, spread the filler out to a distance of two inches (5.1 cm). Maintain a consistent amount of pressure on the putty knife in order to ensure that the wood filler adheres completely. Spread the wood filler to the desired level of thickness and allow it to dry.

    Let the filler dry for 30 minutes. 

    The wood filler will completely set within a half-hour in temperatures cooler than 75 °F (24 °C). In warmer temperatures, it may take as little as 10 minutes for it to set.

    Sanding and Painting Patched Wood

    Smooth the patch with sandpaper. 

    Make sure the edges of your patch are flush with the existing wood, so it has a uniform look. Start with coarse sandpaper, around 60 grit, and work down to a fine-grit paper, like 200 grit, for a completely smooth finish.

    Use a matching stain if the original wood is stained. 

    Paint a coat of the stain onto the wood and let it dry. Be careful not to overlap layers of existing stain since this may make the colour appear darker in that spot.

    • Patches of wood filler may stain a slightly different colour than the actual wood. Test the stain on a small part of the filler to see how it holds the stain.

    Paint at least two layers of primer if the wood is painted. 

    Use thin coats of grey or white primer so you can apply it evenly. Let it dry for 10 minutes before you start on another coat.

    • Use a spray primer for a more even coat and to avoid the look of brush strokes.

    Apply a coat of paint after the primer has dried. 

    Mix the paint with a stir stick, so it's not separated when you use it. Paint thin coats with a paintbrush, so it evenly layers. Use long strokes that cover the entire length of the wood, so it has a smooth finish.

    • The paint should dry within 10 minutes unless it is very humid.

    Repair, Don't Replace, Rotten Wood.

    Wet or dry rot can affect any home's wood. A rotten wooden door, floorboard, trim, window sill, or column may signal serious problems. Rot spreads quickly if not treated as a fungal infestation. Replacing damaged wood is a hassle and can be expensive, but there's good news. Non-structural woodwork rarely needs replacement. Use easy-to-use products to strengthen the weakened area. How-to:

    Eliminate the cause. 

    Missing or loose roof tiles, plumbing leaks, poorly fitting doors and windows, inadequate stone pointing, and condensation allow rot to develop. Dry rot (which, despite its name, requires 20% moisture) causes wood to discolour, split, crumble, or flake and has a mushroom-like odour. Wet rot occurs in areas with at least 50% moisture and causes black fungal growth and a spongy, damp texture. If the problem is indoors, open as many windows as possible and use fans and dehumidifiers to ventilate.

    Remove the rot. 

    Once you find rot in your home, you must remove all affected wood before repairing. Use a 5-in-1 painter's tool or a sharp putty knife to remove rotted wood. Vacuum sawdust and dirt.

    Buy a low-odour, VOC-free wood hardener and filler, polyester or epoxy (VOCs). When handling these substances, wear gloves.

    Apply the hardener with a small to medium brush, filling in cracks and covering the surrounding wood. This will reinforce its structure.

    Next, mix a batch of wood filler. 

    Ready peanut butter consistency. Apply generously (extra can be sanded off later) and shape with a putty knife. For large repairs, build a form to shape the filler. Follow the lead of San Diego handymen and work quickly when using wood filler. As the filler hardens, apply a second and, if desired, a third coat. Sand and clean off any dust.

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

    Prime the repaired section and then paint it to match the rest of the object. 

    For the best results in protecting against potential issues with dry or wet rot in the future, use paint that is anti-fungal.

    A word of caution is in order. When working on rotten wood, it is imperative that you take into consideration the possibility that it contains lead paint. Workplace health and safety precautions must be adhered to in order to prevent the inhalation of old paint dust and the transfer of paint chips.

    FAQs About Wood Rot

    Rotten wood is highly porous and must be sealed before painting. Before rotten wood can be painted, it must be treated with a wood hardener. The hardener absorbs into the rotted wood to provide a firm base for the paint.

    Dry rot is a type of dampness primarily found in aged homes and buildings. If left untreated, it can cause wooden structures to weaken and the building's foundation will get disturbed.

    To help the wood hardener penetrate deeper, drill small holes into the rotten area. It's worth drilling holes in the area that's slightly beyond the rotten wood to ensure the rot doesn't spread. Once you've removed the crumbling wood, use a wet rot wood hardener and apply it to the wood with a paintbrush.

    While dry rot can technically happen to any wooden structure, it's most commonly associated with homes and buildings. Left unchecked, a dry rot issue can be catastrophic, leading to structural failures and collapses.

    Dry rot can spread up to 80 mm per day, if it has optimal conditions for growth. In order to achieve this intense growth, dry rot needs temperatures between 66- and 70-degrees Fahrenheit. Further, unlike many other fungi, dry rot does not need a lot of moisture to grow quickly.

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