How to Repair Rotted Wood

How to Repair Rotted Wood

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There is no denying the fact that anything made of wood looks great. Chairs, tables, stairs, decks, and more, all look fantastic when real and high-quality wood is used. That said, wood does have one big weakness, and that is moisture, and moreover, fungi.

When there is a lot of moisture and a few fungal spores around, the fungus can quickly take hold, which is what causes wood to rot. Fear not though, because a little bit of wood rot is not the end of the world. You may need to replace the wood in some cases, but in many others, you may be able to perform repairs, as long as the rotting is not too extensive.

Can Wood Rot Be Repaired Without Replacing the Wood?

You might be wondering if wood that is damaged by rot, whether a little or a lot, can be repaired or treated without removing and replacing all of the wood. Well, the answer is that in many cases, yes, the wood can be repaired.

The rotten sections need to be treated, although it is usually better to remove the parts with the most severe rot, and then fill or replace those small sections.

That said, rotted softwood is very hard to deal with, and more often than not will require total replacement. Hardwood is much easier to deal with when it is rotten. Moreover, you can repair wood suffering from dry rot, although if the wood in question is designed for structural integrity, such as a ceiling beam, then repairing it may not be the best choice.

The bottom line here is that small repairs are usually fine, but if a significant portion of the wood has been affected by rot, then you may need to replace the wood, because if too much is rotten, then the overall integrity may be compromised to the point where the wood can no longer do its job.

One thing to keep in mind: structural wood absolutely needs to be replaced, not repaired!

How to Repair Rotted Wood: Four Methods

There are four methods for repairing rotted wood that are worth talking about. Once again, remember that all of these methods are for relatively minor damage. Extensive rotting, particularly when structural integrity is in question, will require total replacement.

Method #1: Removing the Rot

This first method is fine if there is just a little bit of rot, a very little bit. This method involves simply removing the minor portion of the wood that has rotted and then sealing it (without any further repairs).

Keep in mind that this method is something you need to do first even if you decide to use the methods listed further down (other than using method 3 which does not require this step.

Step 1: Remove the Rotten Wood

Using the claw on a hammer, remove as much of the rotten wood as you can. You probably won’t be able to remove all of it with just a hammer. Use a router with a V-bit to drill out the rest of the rot, using short back-and-forth strokes. You cannot leave any rotten sections, or else the rot will likely continue to spread.

Step 2: Sand the Surface

You will need to apply some wood restorer to the area, but before you can do this, you need to use some coarse sandpaper to sand away any residue, so that the wood restorer can adhere.

Step 3: Apply the Wood Restorer

Get some basic wood restorer (more or less a protective bond and layer designed to hold everything together and to prevent moisture from penetrating the wood). Use a small brush to apply about six layers of it, waiting two to three minutes between layers. Allow the wood restorer to dry for two hours.

Technically speaking, the damaged section is now removed and repaired, and you could leave it as is, although if you want to make it look nice, you will want to replace the missing section, which is where the next method comes into play.

Method #2: Patching the Rotted Section with Epoxy

You can now use some epoxy to replace the small missing section of wood that you removed above.

Step 1: Apply a Bonding Agent

So the epoxy can actually stick to the wood, you first want to use a paintbrush to apply a bonding agent to the surface.

Step 2: Mix and Apply Epoxy

You need to purchase a two-part epoxy designed for wood repairs. Mix as much of the epoxy as needed, and then use a tool like a scraper to apply it to the area. Make sure to use the epoxy within about 20 minutes of mixing it, or else it will start to dry out. Apply as much as is needed.

Step 3: Shape the Epoxy

Before the epoxy dries, use a scraper or any other tool to mold it to the appropriate shape that it needs to be in once fully dried. Now you need to let the epoxy dry.

Step 4: Remove any Excess

Once the epoxy is dry, use a sharp scraper to remove any excess that is left over, so that the repaired section is flush with the original wood.

Method #3: Making a Wood Patch

You may also saw away a decent portion of the wood, everything that is rotten, and then cut a new piece of wood to replace the missing section. In this case, as mentioned earlier, there is no need to seal the removed area.

Step 1: Remove the Rot and Make a Square

Use something like a Japanese handsaw to remove the rotten wood, or a jigsaw works fine too. However much you remove, make sure that you are left with a missing square or rectangle with 90-degree angles.

Step 2: Cut the New Wood

Get your new wood and cut a piece to size, the same size and shape as what you removed in the first step. Make sure to use the same kind of wood, and be sure to go for quality. You don’t want to replace sections with lackluster wood that is just going to rot again.

Step 3: Moisten the Area

The glue that you will use for this process activates and adheres much better with some moisture, so use a wet rag to moisten the exposed area of the original wood, as well as the new piece you will be inserting.

Step 4: Apply Glue and Screws

Now you can put a good bit of polyurethane wood glue on both pieces, and then neatly place the new piece into the missing section. Make sure that everything is flush and even, and once it is, for a bit of added holding power, fire a couple of screws into it.

Step 5: Finish the Job

Once the glue is dry, you can use some sandpaper to even things out and to remove excess glue. At this point, you may also paint or stain the wood as desired.

Method #4: Using Wood Filler

The final method you can use is to fill the “hole” that you created in method #1 using some good old wood filler or wood putty.

Step 1: Mix the Wood Filler

Most wood fillers come with two parts, the filler itself and the hardener that will cause it to harden. Get something like a little cup or some kind of container that you do not plan on using again, and mix the hardener and the filler according to the directions.

Step 2: Apply the Filler

Using a putty knife or any other such tool, apply the wood filler as needed. Make sure to spread the filler a few inches past the problem area, just to be safe, as this will provide some added protection. Smooth it out using your putty knife, and then let it all dry according to the directions.

Step 3: Finish It Off

Once the filler is dry, you can then sand it down as desired, and if you got filler that can be painted, now is the time to paint.

Mistakes to Avoid, Tips & Tricks

To make your life a bit easier, let’s go over a few tricks to make your rotten wood repair job as successful as can be:

  • First and foremost, if the rotten wood is structural in nature, it should be 100% replaced, not repaired. You don’t want to take chances here.
  • Wood rot often spreads further than the eye can see. If only an inch looks rotten on top, chances are the rot is more severe. It often looks less severe on the surface.
  • When removing rotten sections, always go a couple of inches past where you can see. In no case do you want to leave any amount of rot behind, as it will just continue to spread, even after everything else is replaced.
  • You need to exercise some common sense here. For instance, if literally half of a board is rotten, it might cost you more to repair it than to replace the whole thing, not to mention that when large portions of wood are rotten, exactly how effective or long-lasting repairs will be is questionable at best.
  • Always wear proper protection when working with any of the chemicals or substances we talked about today.


There you have it folks, a few different methods that you can use to repair rotten wood.

The most important sentiment of the day is that you need to use your own good judgment and common sense to determine whether a repair or a total replacement is the way to go.