Woodworm or beetle attack of timber

Technically speaking, what you see in a piece of timber is little holes that are left when adult beetle emerge from timber after they have lived and grown inside the timber as grubs.  Most holes that we see in surveys are over 100 years old - some over 400 years old.  The vast majority of 'flight holes' date back to one or two years after the tree was felled - beetle had laid eggs in the timber whilst it was growing - under the bark, and they were happily tunnelling away under the bark, living on abundant supplies of moist, green, starchy wood.  When the tree is felled, the grubs continue to live and eat until the timber slowly dries out and the grubs mature.  As they reach adulthood, they tunnel their way out of the wood, and emerge to fly off and find another tree in which to continue their life cycle.  

Old timber was cut up over pits.  It was nearly always 'quarter sawn' - which means that we usually see beetle holes on one side of the timber - the outer, rounded bit nearest the bark.  They don't inhabit the harder inner 'heartwood', only the sapwood.

So - you can see that beetle don't really fit inside your house.  The horror picture that the Property Care Association 'timber and damp' surveys tell you, of beetle 'infestation' and the need to drown your house in litres of toxic chemical soup, is complete rubbish.  British households have been conned and duped for years into this ridiculous and uneccessary practise, netting the damp industry hundreds of millions of pounds.  It is a very clever con trick.  

Luckily for us, a lot of research has clearly established that these treatments are not needed.  This is now neatly summarised in the new BS 7913: 2013 Guide to the conservation of historic buildings, published jointly by the British Standards Institute, and the Institute of Historic Building Conservation (BSI and IHBC).  Section 6.10.3 - 'Insect attack' includes the following statement: "The principal objective should be to remove the sources of moisture..."  it goes on to say this about chemicals: "Insecticidal treatment should only be used as a last resort as it can cause environmental damage and might require licenses of protected species.  Precautionary treatment should NOT be applied to unaffected timbers." These are powerful words - and clearly establish that wholesale and automatic 'timber treatment' should NOT be undertaken.  This statement is made partly because timber treatments have been poisoning bats which collect in groups under roof timbers. When restoring old properties, we have to take bat habitats into consideration.  These lovely little creatures do us no harm, and consume vast amounts of insects on a nightly basis - but are very sensitive to chemicals - hence the warning in BS 7913 that timber treatments should not be applied.

For years, Property Care Association 'timber and damp' reports have recommended automatic drenching of Britain's homes with chemicals.  Every time the home changes hands, the local timber and damp contractor repeats the exercise - resulting in a gradual toxic accumulation within timbers.  We are now seeing the result of this in an interesting but seriously concerning way:  When examining timbers in old houses with a protimeter, we are getting high 'damp' readings in perfectly dry timber. This is because the timbers are so coated with toxic chemicals, that they are becoming conductive even when bone dry. This is of serious concern and another reason for bringing this shameful practise to an abrupt halt.