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Joinery

We use the term 'joinery' on this site very loosely - it's a catch-all phrase to cover everything timber.  So you'll see pages covering timber frames, sash windows, and wooden floors as we add content.  I've put a few summary words about 'woodworm' here - but we will add more details with photos on following pages as time permits.

The most important thing about historic timber, or anything wooden in an old house, is to understand why it deteriorates.  Moisture is the culprit - and the less there is, the more chance the timber survives intact.  We use a break point of around 20% TMC (Total Moisture Content) for timber - anything less than that and it should not deteriorate.  When surveying timber in old houses, we look for two things:  Signs of beetle activity, and fungus / mould.  Beetle are seldom active in timber that is less than 17% TMC - so if timber is dry - no beetle.  It is now clearly established scientific fact that timber does NOT need treating if it is dry.  

If you happen to be unfortunate enough to be on the receiving end of a Property Care Association 'timber and damp' report, you will be told that all of the timber should be 'treated' with toxic chemicals.  This is NOT necessary - according to the new BS 7913: 2013 Guide to the conservation of Historic Buildings, timber treatment is rarely if ever justified.  It is also clearly established fact that chemical treatment does not penetrate timber - it only sits on the surface.  Beetle burrow deep into timber and reproduce within tunnels inside the timber - where chemicals can't reach.  They feed on starch - and prefer the timber to be slightly damp.  All the beetle holes we see in timber are what we call flight holes - they only appear when the bug emerges and flies away. Most are hundreds of years old.  Beetle don't attack the heartwood of oak - they generally only live in the sapwood - which is why you see so many holes on the edges and rougher bits like bark - but not in the middle of beams.  

Pete recently built a timber framed conservatory at his house, from green French oak.  Two years later, beetle started to appear from the sapwood of the timber.  After 6 months of emergences, they stopped - and no more have been seen since.  Beetle attack of French oak is well known - their trees are infested with the things, and the timber is full of them when it arrives in containers in this country.  Our advice - avoid French oak like the plague, and insist on English oak.  Death watch beetle are the same - again, only like damp timber, and cannot be killed with chemicals - dry the timber and they go away.

  • Beetle attack of sapwood in oak
    Woodworm or beetle attack of timber

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