Most woodworm infestations can be treated with DIY skills and tools. Read the guide below with woodworm advice and a full explanation of how to treat for wood boring insects in your home.
Woodworm Treatment Advice and Woodworm Diagnosis
There are three types of woodworm in the UK and we have pictured them below for easy identification and to help you diagnose the different types of infestation if you think you have woodworm evidence in your home. Pictured also is the damage each one causes to the timber, because it does differ for each different type of woodworm.
The Common Furniture Beetle which is what we normally refer to as woodworm.
The House Longhorn Beetle is rarer but much more destructive, more on this later in the project.
Last but not least the Death-Watch Beetle, which is the one that sounds the worst! We explain the process for treating this destructive beetle at the end of the project.
The first thing you will notice is that they are all beetles and not worms at all. I think most people realise that the worm bit in woodworm refers to the larvae state when the beetle is a grub that looks more like a maggot, so is known as a wood 'worm'.
Is the Woodworm Still Active or Not?
There is a common misconception that woodworm is inactive once the holes appear in the wood. While it means that that particular 'worm' has grown up and left the nest as a beetle it does not mean there are not more in the wood, and in fact that same beetle may be back to lay its eggs starting the whole woodworm lifecycle off again.
So how do you tell if the woodworm is active or not? If the woodworm is still active there will be signs of droppings or frass, which looks like fine sawdust, around the affected area.
I remember carrying out work for a letting agent in Somerset where a tenant was so concerned about the woodworm that was in the furniture that she lay in wait for confirmation of the beetles emerging so she could confront the landlord with it. Indeed she captured her evidence and brought it into the Letting Agent's office in a jar, at which point the landlord had to agree to treat the woodworm!
If the wood was good for woodworm once it will be a good feeding ground again if it remains untreated. As woodworm and damp often go together an attack is a good indicator that your timber is not in good condition.
Common Furniture Beetle or Woodworm
Woodworm in Furniture and Other Timber
If you see very small holes scattered across the surface of timber or furniture, you have evidence of woodworm. There are usually a cluster of holes and each hole is around 1-2mm wide.
As mentioned at the beginning, these holes are where the adult beetle has emerged from the wood after spending the primary part of their lifecycle as a larva within the wood. They are therefore known as emergence holes or exit holes.
While woodworm is in the larval state they tunnel their way through the wood. The damage they do is mainly cosmetic unless there is also damp in the wood, or the timber is very slender. Obviously it is still better to treat the wood, but it is not usually cause for alarm if you find evidence of this common furniture beetle.
As the name suggests they are the most common species of woodworm. They attack softwood timber like pine but they are very at home in plywood and may stay within it for prolonged periods of time especially if the conditions are slightly damp.
Woodworm and Damp
While conditions do not need to be damp for woodworm to survive they will certainly thrive where the timber is moist. Therefore damp floorboards or loft timbers are prime real estate for woodworm, but of course they will also make a home in our furniture, and because this is under our noses we are more likely to spot woodworm damage in furniture.
Beetles are most likely to choose untreated wood to lay their eggs so you are most likely to find woodworm in furniture where the polish or finish has worn off, and where it is kept in damp conditions. However the woodworm will live in other conditions, so don't discount it just because the conditions are not ideal for it.
If you have woodworm in furniture but you have other timber in the house that makes a better home for the beetles to lay their eggs they will find it! So it is much better to treat when you see evidence of woodworm.
Woodworm Treatment - Common Furniture Beetle
We would recommend that for DIY purposes the best woodworm killer and timber treatment to use is Boron Ultra 12 because it is a water-based product that only kills wood boring insects, does not give off unpleasant fumes or smells and quickly soaks into the timber. This is available online from Property Repair Systems on the link above.
Many contractors use a chemical called Permethrin but this has unpleasant vapours and smells and it is also hazardous to other insects and even mammals, which is a consideration if you have bats in your belfry. Bats are a protected species and it would be illegal to carry out work or treatments that would cause harm or disturbance to roosting bats, so bear this in mind if you are treating woodworm in your loft or attic.
If you are using powder dilute a 5% solution and apply two coats of the Boron Ultra 12 by brush or spray. Allow each coat to dry before applying the next.
The 1kg bag pictured above dilutes in water to make 25 litres of Woodworm Treatment at 5% solution. This should be applied until the area is fully wetted but not dripping. It should cover at a rate of approximately four square metres per litre of solutions.
Make sure you wear a dust mask and gloves, and avoid splashing the solution on bare skin.
Preparing the Boron Solution
The Boron Ultra 12 powder can be dissolved at the following rates to treat the following areas. Use our Handy Preparation Table below
|Quantity||Makes||Covers (in 2 coats)|
|100 grams||2.5 litres||5 Square Metres|
|200 grams||5 litres||10 Square Metres|
|500 grams||12.5 litres||25 Square Metres|
|1 Kg||25 litres||50 Square Metres|
|2.5 Kgs||62.5 litres||125 Square Metres|
For commercial use the Boron Ultra 12 can be mixed and used at 10% solution, which is useful where infestation is heavier. For DIY use see Heavy Infestations below.
We would suggest that very heavily infested areas of timber are also treated with Boron Ultra Gel, to provide further active ingredients to ensure the whole infestation is cleared in one treatment.
Boron Gel woodworm treatment is available from Property Repair Systems for DIY purposes as a 5% solution and for trade at 20% in quantities of 500ml, 1 litre and 2 litres. See the table below for coverage.
The Gel should be applied by brush liberally to the affected area, but do not leave excess on the timber as it can crystallise. Remove any excess gel with a dry cloth.
|2 litres||8 Square Metres|
|1 litre||4 Square Metres|
|500ml||2 Square Metres|
Infestation and Damp
It is advisable to treat the area with Boron Ultra gel where there is damp present in the timber as it will act as a preservative and provide extra protection against rot and infestation. See above for use and coverage rates.
You can return to the area which has been treated with pesticide in one hour or when the product is dry whichever takes longer. This is known as the re-entry time The guideline is set by the Health and Safety Executive (HSE).
While pets, birds and fish are not at risk from Boron-based preservatives, Permethrin-based woodworm treatments can be harmful to pets. It is absolutely lethal to fish even in minute quantities. Permethrin is in most DIY treatments available in the DIY Sheds and high street stores.
House Longhorn Beetle Woodworm
For those of you who do not live in Surrey you will be pleased to know that the House Longhorn Beetle (Hylotrupes Bajulus) is not very common in the UK.
If you do live in Surrey and you have woodworm you should be very careful to make sure you get correct diagnosis of your woodworm.
Where the House Longhorn Beetle is in evidence it prefers roof timbers and only attacks softwoods. Unlike the Common Furniture Beetle the larvae of this species causes holes and tunnels in the wood that are much bigger than the furniture beetle and infestation does cause severe structural damage to the timbers.
If you suspect infestation you should contact your local council and get professional advice as soon as possible. You can also notify the Building Research Establishment (BRE). The BRE monitor the spread of this destructive beetle and they produce reports on the spread of the beetle across the home counties.
Woodworm Treatment - House Longhorn Beetle
Do not attempt to treat infestations of the house Longhorn Beetle as a DIY task. As it is so destructive it should only be handled by a professional who can advise on the structural damage caused as well as the treatment necessary.
For a qualified Timber Treatment company you can find your nearest PCA Member or Property Repair Systems would be happy to provide you with details for your nearest registered member. Call them on 01626 336180.
Death Watch Beetle Woodworm
Death Watch Beetle sounds so terrible but in fact it is not a serious as a Longhorm Beetle infestation.
Death Watch Beetle is relatively common in Southern England, whereas the North of England and Scotland are largely unaffected. It tends to infest hardwoods such as elm and oak. Imported timbers are more likely to be attacked, with French Oak being a particular delicacy for the beetles. However once it is over here it will also lay eggs in softwoods.
This woodworm prefers its timber to be damp and even wet. It is especially happy if there is also fungal decay (wet rot) in the timber too. Funny what sort of home some species like isn't it? So to truly thrive this beetle wants conditions that you would not want in your house in any event, so it is not a very common pest for that reason.
Unlike the Common Furniture Beetle this woodworm has a ten-year life cycle which does make treatment a bit more difficult. The Death Watch Beetle is also much more destructive while it is feeding on the timber and can cause severe structural damage to timber including large structural timbers.
Woodworm Treatment - Death Watch Beetle
The feeding patterns of the Death Watch Larva will leave sections of the timber hollow so to find out which areas need treating tap or 'Sound' the timber with a hammer.
You will be able to hear the difference between solid timber and any hollow sections.
Test these hollow areas by drilling into the affected areas with an 8 - 10mm diameter auger, so you can establish the parameters of the infestation.
When you have worked out where you need to treat you can inject Boron Ultra Paste into the affected areas.
Drill into Timber
Drill 10mm diameter holes to within 15mm of the opposing face, using the drilling pattern provided by Property Repair Systems which is available to download free here.
The guide is also provided in the treatment kit from PRS provided with the Boron Ultra Paste. See below for an example of the pattern of holes to be drilled to ensure even treatment:
Fill the holes you have drilled with Boron Ultra Paste. Making sure the hole is completely full from the bottom to the top, using an extension tube (see below). Cap off the hole with a timber dowel or plastic cap. Remove any excess paste with a cloth to prevent crystals forming.
Treat the Surface
Once any paste left on the surface is dry, brush on two coats of Boron Ultra Gel to all affected areas. Apply the gel onto sound timber by at least 300mm all the way around the area that was subject to attack. Allow each coat to dry in between coats.
Because the lifecycle of the Death Watch Beetle is so long, you should continue to check for infestation on an annual basis for at least ten years.
If you spot signs of activity you will need to re-apply woodworm treatment or where necessary.
Please note - Surface treatment alone is not sufficient to deal with Death Watch Beetle, you do need to get the treatment into the core of the timber. If you do not want to tackle this task as a DIY project, you should get professional help and advice from a knowledgable and reputable specialist.
Preventing Re-Infestation of all Woodworms
We advise that you carry out annual inspections for signs of woodworm activity, and treat again as necessary.
We hope that you have found this project on woodworm advice, treatment and diagnosis guides for the different types of beetle useful. If you are still unsure about woodworm infestation or treatment and would like additional help and advice then contact Property Repair Systems qualified staff. You can take advantage of their specialist knowledge by calling them on 01626 336180. They offer completely free, no obligation advice and we have worked with them for many years now and can confirm that they really do know their stuff!!