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How to Repair Rotted Wood

Resin application onto a wooden window frame

Older properties can be susceptible to damp and timber issues as a result of a compromised damp proof course (DPC) and/or poor ventilation resulting in rotted wood, but decaying timber can affect any home at any stage if the right conditions are in place.

Depending on where the wood is, the threats posed by rotted wood can be substantial and extend further than simply the aesthetic appearance. For this reason, treating rotted wood at the very first sign is essential, but first, you’ll need to know what kind of problem you’re dealing with before you can effectively treat it.

Types of Wood Rot 

There are two main types of timber decay: wet rot and dry rot.

Dry Rot 

Despite its name, dry rot does require a level of moisture to be present, but it is such a problematic form of timber decay because it occurs with as little as 22%-28% moisture. For reference, normal moisture levels in dry wood is between 8% and 16% depending on the size of the wood and the surrounding conditions, it’s clear to see why so many homes are affected by dry rot.

Signs of dry rot include:

  • Timber that crumbles to the touch
  • Brown, red or orange spore dust patches
  • Fruiting bodies resemblant of a mushroom
  • Cuboidal cracks in timber with grey strands stretching across
  • A musty smell
  • Sap between skirting boards and flooring and architraves and walls

You may notice some of these symptoms on masonry and soil, too.

Dry rot is incredibly destructive and can spread fast, resulting in severe structural damage if not diagnosed and treated early on.

Wet Rot

Wet rot often requires a much higher level of moisture to come into fruition – usually around 50% as a bare minimum. The level of moisture required means that if you have wet rot anywhere in your home, you likely have a serious damp issue that will need to be looked at urgently.

If you have wet rot, you’ll likely notice:

  • Dark patches on timber if a brown wet rot attacks
  • Shrinking timber
  • Wood feels springy or bouncy to touch
  • Damaged paintwork (crumbling or peeling)
  • A musty smell
  • Cuboidal cracks within the timber with brown wet rot, and stringy, fibrous strands of timber with white wet rot
  • A bleached appearance on wood if a white wet rot attacks

Some of these symptoms are alike those of dry rot, but key things like wood being wet to the touch or feeling bouncy will generally tell you what type of damp you’re dealing with.

If you’re unsure and are based in the London area, arrange a site survey and no-obligation quote through Garratt’s Damp & Timber.

Treating Rotted Wood 

Whether you’re dealing with wet rot or dry rot, any form of timber decay needs to be thoroughly treated. We always recommend employing a professional team to carry out the treatment to ensure the root cause is identified and the most effective solution is administered to solve the issue as quickly as possible.

How to Repair Rotted Wood

In instances of minor timber decay (less than 50% damage), it is possible to fix rotted wood yourself. Of course, if the issue is far-reaching, you should look at hiring a professional team to replace rotted wood in your house, but in smaller instances where the source of the decay has been identified and treated, you may be able to fix the appearance yourself using the following steps.

Beware, misdiagnosis and incorrect treatment can prove very costly.

  1. Remove the affected areas 

The first step repairing decayed timber is to carefully remove the affected area using a chisel. You’ll want to be as precise and delicate as possible, taking care not to remove healthy wood or further damage the timber. A good approach is to work in sections. You can always remove more, but you can’t put it back once you’ve chiselled it out!

When you’re sure you’ve got rid of the problematic wood, use a delicate kabuki brush to remove debris and dust in preparation for the next step.

  1. Add a layer of wood hardener 

As mentioned previously, the leading cause of wood rot is excess moisture. To prevent further moisture from getting in, add a layer of wood hardener to the chiselled areas. The hard resin will seep through the wood and form a seal that will keep unwanted moisture and water out, reducing the likelihood of future rot issues. You can use a paintbrush to apply the resin, making sure you cover all the exposed areas.

  1. Add filler 

Next, you’ll want to fill out the chiselled away areas so that there is an even finish free of dips and cavities. You can achieve this by using wood resin or epoxy. To apply, you’ll need to use a putty knife. You will need to work quickly and make sure with every layer you add, you smooth it out and remove excess before it dries and hardens.

  1. Sand the areas down 

In all the areas you applied filler, you’ll want to sand them down for an exceptionally smooth finish that is consistent with the rest of the wood. It’s a good idea to sand the entire piece of timber down when you’ve sanded the filler areas because the next step is to paint, and you’ll want to ensure you have an even canvas to avoid patchiness and inconsistencies in the look and feel of the wood. Sandpaper is sufficient for this.

  1. Prime and paint 

In the case of painted wood, you’ll want to make sure you effectively prepare the timber by priming it first. Primer is typically applied the same way as paint using a paintbrush and is designed to protect the wood and increase the longevity of the wood. Once you’ve primed, you can use wood-specific paint.

The end result should be a completely smooth and fully repaired piece of wood. To preserve the finish, you’ll want to make sure you directly address what caused the decay in the first place e.g. a leak, failed DPC or poor ventilation. We are specialists in treating the aforementioned issues.

Get in Touch 

If you have any questions or concerns surrounding timber decay, treatment and replacement, please don’t hesitate to contact us and we will be more than happy to help.

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