Poulton Remedial Services - Timber Infestation

The grubs or larvae of certain beetles principally Lyctidae and Bostrychidae derive nourishment from starch or other carbohydrates present in softwood cells for some time after the timber has been felled.

Others like the Anobiidae feed on the wood substance, consuming cellulose and other constituents of the cell wall.

The life cycle of all wood destroying insects start with the laying of an egg. This egg then hatches into a grub or larvae which bores into the wood often over a period of years.

It is this action which causes internal damage to timber.

The larva eventually creates a chamber just below the surface of the wood and it is here that pupation, the transition from grub to crysalis, to the adult beetle takes place.

After pupation the adult beetle chews its way to the surface of the wood creating a noticeable exit hole. Mating then takes place, the female lays further eggs and the life cycle is repeated.

1. TYPES OF WOOD BEETLE

Common Furniture Beetle (Anobium Punctatum). Commonly referred to as woodworm this beetle attacks hardwoods and softwoods in buildings throughout Britain.

Adults emerge between May and August and can be seen on walls, ceilings or windows. Females lay up to a hundred eggs. The average life cycle is three years, but individuals can be longer. Because of this variation, there are frequently larvae of all sizes present after the emergence of adult beetles. The beetles are between 2.5 and 5mm in length and reddish to blackish brown in colour and upper parts of the body are covered in short yellow hairs. Flight exit holes are circular and 1-2mm in diameter.

It has been estimated from various surveys that Anobium is infesting (to some degree) 80% of houses over 40 years old in rural areas

Death Watch Beetle (Xestobium Rufovillosum). A serious pest in old houses, churches etc. It tunnels in oak and other hardwoods but may also be found in softwood. Flight exit holes are circular and between 3mm and 5mm in diameter. The larvae may live for up to 10 years within the wood.

House Longhorn Beetle (Hylotrupes Bajulus). This beetle infests softwoods and causes serious damage to roof timbers in particular. Mainly confined to Surrey and the vicinity, flight holes are oval, often ragged and 6-10 mm in diameter.

Powder-Post Lyctus Beetles (Lyctus Brunneus). This beetle attacks the sapwood of many hardwoods damaging floors, panelling, plywood etc. Flight holes are circular and 1-2 mm in diameter.

Wood Boring Weevil (Pentarthrum Huttoni and Euophryum Confine). These insects damage wood by making channels in it and are associated with damp and decay. In active infestations, large numbers of weevils are found crawling about on the wood. Emergence holes are circular and 1mm in diameter.

2. TYPES OF PRESERVATIVES

The most commonly used are liquid treatments which consist of a persistent contact insecticide and are intended to kill insects already within the timber by penetrating the timber and killing larvae within the applied zone (initial kill). By leaving a persistent layer of insecticide in the penetrated zone, it kills successive generations of emerging adults developed from surviving larvae. This layer prevents further infestation from hatching larvae boring into the timber.

1. Organic Water based Preservatives.
   These consist of fungicides or insecticides dissolved in a water carrier which evaporates from the wood after treatment. The active ingredients include fungicides such as Organoboron and insecticides such as Permethrin.
2. Water-borne Preservatives (emulsions).
   Traditional water borne preservatives use Boron compounds and are used in the pre treatment industry. Poulton Remedial Services use water based emulsions which are safer to use than traditional solvent based products and create much less fire risk.
3. Paste Preservatives.
   High bodied paste type preservatives have been in use in the UK since 1960. They comprise a water based emulsion containing active fungicides and insecticides and provide deep penetration in timbers. They are especially suitable for timbers of low permeability.

3. METHODS OF APPLICATION

1. Brushing
   Apply the preservative liberally in flood coats especially at the timber ends and joints.
2. Spraying
   Spray applications of wood preservatives is the generally accepted method of treatment by Remedial Contractors. Poulton Remedial Services operators use spraying equipment giving a coarse low pressure spray. The preservative is flooded onto the surface until run off occurs.

In roof voids the rafters and joists are brushed down to facilitate effective treatment. Fiberglass insulation is lifted and replaced after treatment. Where boarded floors are to be treated, sufficient boards are lifted to give access for the treatment of joists and wall plates. Boards are replaced and the surface of the floor is flooded. In the case of Death Watch Beetle organic solvent is used with a full bodied emulsion where infestation is serious. Staircases are usually painted and the underside often lined with plasterboard or boarding. Treatment in these areas consist of drilling the risers and spraying into the drill holes with a back spray nozzle.

4. HEALTH & SAFETY

All chemical pesticides used in remedial wood treatments are subject to assessment for safety in use under the Control of Pesticides Regulations 1986 and only products cleared under these regulations are used by Poulton Remedial Services.

It is an offence under the Food and Environmental Act 1985 to use products which are not approved under these regulations.

The British Wood and Damp Proofing Association of which Poulton's are members have issued a code of practice which include requirements for the safe use of remedial treatment chemicals. All member firms are required as a condition of membership to comply with the safety advice issued by the BWPDA. www.bwpda.co.uk