Round holes in a beam and a small pile of fine dust beneath: that is the classic sign of woodworm larvae living in the wood. In this category you will find products to treat affected wood in sheds, stables, lofts and outbuildings: the Edialux woodworm treatments Perfacs and Perwood, Resoluut Houtworm Concentraat and Wolsit KD 10. They differ mainly in pack size and in whether you buy them ready to use or as a concentrate.
Woodworm or longhorn beetle?
What you see determines how big the problem is.
- Common furniture beetle (woodworm) leaves small, round exit holes of about 1 to 2 millimetres, often in furniture, floorboards and older structural timber.
- House longhorn beetle makes oval holes of about 6 to 9 millimetres and mainly attacks softwood in roof structures and joists. The larvae can feed inside the wood for years before you see anything.
Fresh, light-coloured bore dust under the holes points to active infestation. Old, dark holes without fresh dust may date from long ago.
Which product and how much
For a single beam, a cupboard or a few boards, a 500 ml or 1 litre bottle of Perfacs is manageable. A whole roof structure or many square metres calls instead for a concentrate such as Resoluut Houtworm Concentraat, or for Perwood in a larger pack. Calculate consumption using the dosage on the label and the area you are treating. Some large packs and concentrates are aimed at professional users; check on the label who may use the product.
How to tackle it
The product must be able to soak into the wood. So first remove paint, varnish or wax and vacuum away bore dust and dirt. Then apply the product with a brush or sprayer, and in badly affected spots also into the exit holes. A suitable pressure or knapsack sprayer is in spraying equipment. Wear the gloves and respiratory protection stated on the label; see safety and protection. Keep animals, feed and drinking water away from treated wood until it is safe according to the label.
When to call in a professional
If a load-bearing beam is so badly affected that it feels soft or sags, a treatment will no longer help: then an expert needs to look at the structure. That certainly applies to house longhorn beetle in a roof structure.
Other pests in and around buildings are in crawling insects and proofing and screening. Back to pest control.
Frequently asked questions
How do I know if the woodworm is still active?
Look for fresh, light-coloured bore dust under the holes and for new holes. Sweep the dust away and look again after a few weeks; if fresh dust appears, the infestation is active.
Can I treat varnished wood?
The product does not penetrate paint or varnish. Sand or strip the finish first, so the product can soak into the wood.
Can animals stay in a stable where I am treating wood?
Keep animals, feed and drinking water out of the space during and after treatment, for as long as the label states. Ventilate well.