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Timber Infestation by wood boring insects
There are many different types of wood borers that may attack the
insitu timber within a property, which over a period of time could
lead to considerable damage. The life cycle of a wood boring insect
commences with the laying of the insect egg, on the timber surface
which subsequently hatches into grubs or larvae, which bores into
the timber and continues tunnelling over a period of 3-15 years
depending on the species of wood borers. During this stage when
the grub or larvae is active within the timber, (woodworm) the majority
of damage is caused to the timber. |
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Common Furniture Beetle (Anobium punctatum) This is the most commonly occurring wood boring insect in the UK and is usually referred to as ‘wood worm’. The beetle normally attacks softwood timber, but on occasion may affect the sap wood timber of hard wood in close proximity. |
Common furniture beetle (Anobium Punctatum) Magnified. |
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Death Watch Beetle (Xestobium rufovillosum) This insect commonly attacks oak or other hardwoods but may be found in softwood timbers in close proximity. This insect causes more damage to the timber due to its larger size in comparison to the common furniture beetles, and its longer life cycle which may be up to 15 years. Often found in churches or historical buildings.
Typical damage to roofing timber
Typical damage to roofing timber
Typical damage to floor joist
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Picture – Death Watch Beetle (Xestobium Rufovillosum) Magnified.
Typical damage to roofing timber |
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Wood Boring Weevil (Penatarthrum huttoni or similar related species) These particular wood borers commonly attack timber associated with dampness or at least with a higher moisture content level than normal, usually found within sub floor void areas, affecting timber plates, floor joists and the underside of floorboarding, often where timbers are in contact with damp brickwork, plaster or masonry. This insect is more often than not found in association with Wet Rot decay of one species or another. The Wood Boring Weevil will expire once the source of dampness raising the moisture content level of timber has been reduced or removed. Lack of sub floor ventilation to floor voids, i.e. blocked or obstructed airbricks or the lack of airbricks, can increase the high moisture content level of timbers in floor voids. |
Wood Boring Weevil. |
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Bark Boring Beetle (Ernobius mollis) The Bark Boring Beetle will only attack the bark left on the waney edges of old timbers, usually in roof void areas. Once this bark has been removed, the Bark Boring Beetle will expire naturally and no treatment is usually necessary. Often the Bark Boring Beetle flight holes can be confused with Common Furniture Beetle (Anobium punctatum) which may also be in the same areas. |
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House Longhorn Beetle (Hylotrupes bajulus) This large wood boring insect is found affecting softwood timber and can cause a considerable amount of serious damage to roof timbers, if left unchecked for any length of time. This wood borer is rare in this part of the country and is more commonly confined to the Surrey and surrounding areas, but as a member of the BWPDA, we have a duty to report this wood boring insect to the BWPDA when noted for them to log on their records. In association with treatment to eradicate this wood borer, extensive repairs are often necessary to the timbers, with replacement timbers of a tanalised treated type. |
House Longhorn Beetle.
Typical House Longhorn Beetle damage. |
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Timber treatments against wood borers Eradication or treatment of wood boring insects and in particular the Common Furniture Beetle (Anobium punctatum) and the Death Watch Beetle (Xestobium rufovillosum), is “relatively simple” involving the application of a suitable preservative fluid ideally an insecticide/fungicide, but of course a pure insecticide based preservative would suffice, which must be applied to the timber usually by pressure spray and to refusal to accessible surfaces. The cleaning of timbers in preparation for treatment is normally necessary, however modern preservatives used by Bensleys are for the most part “water based” and classified by the Health and Safety Executive, for treatment of insitu timbers in occupied premises as a one hour re-entry preservative. The application of the preservative to the surface of the timber, will enable the preservative to spread into the timber through the cells, penetrating to a depth necessary to allow the pupating beetle in chambers below the surface to become affected and expire before emerging and where larvae are tunnelling near the surface of the timber, result again in the expiry of the larvae or grub. The preservatives leave a persistent layer of insecticide on the top surface of the timber which will kill any emerging adults and prevents further infestation or laying of eggs to the surface of the timbers. It may be necessary on some occasions to apply a deep penetrative preservative paste or gel, depending on the extent of the infestation, location or timber type, i.e. hardwood or softwood. |
Treatment of roofing. |
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Dry Rot (Serpula lacrymans) and Wet Rot (Coniophora putteana, Fibroporia vaillantii or any similar related species of Wet Rot) Infection by wood rotting fungi to timbers in a property is normally related to a high moisture content, often when untreated timbers come in contact with damp masonry, brickwork or plaster, and are allowed to remain in the same condition without being isolated, and with the moisture content level of the timber rising, the timber becoming prone to attack by one or more species of wood rotting fungi. There is only one true Dry Rot fungi (Serpula lacrymans) and all other forms of timber fungal decay are commonly collectively referred to as Wet Rot. There are many different species of Wet Rot decay, however in most circumstances the decay of timber caused by Wet Rot will cease when conditions conducive to its well being, i.e. excessive moisture, have been permanently eliminated. Unfortunately however the eradication of the wood rotting fungi Dry Rot (Serpula lacrymans) has far more reaching implications, the standard rule of thumb in the industry with regards to the eradication of infection from the wood rotting fungi Dry Rot is to strip approximately 1 metre beyond the last sign of the spread of the infection in all directions. This normally including the removal of fabrics such as plasters and renders internally, and including for cutting back of timbers both structural and joinery, and can involve the removal of window/doorframes or hidden timbers etc. Specialist treatments will usually include drilling and irrigation of masonry plus treatment of retained timbers. The most important aspect, is to establish the full extent of fungi and confirm the species present. |
Dry Rot Fruiting Body (Sporophore) Plate Shaped.
Dry Rot Fruiting Body (Sporophore) Bracket Shaped.
Dry Rot Fruiting Body and mycellium growth on carpet underlay and skirting.
Wet Rot decay to skirting board.
Wet Rot decay to skirting board. |
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