28-08-2012, 11:15 AM
There is a lot of conflicting opinion about woodworm treatment...
There is no doubt that the female will want to lay her eggs in the best place, which means reasonably moist sapwood. They can't survive in the dry, and they need to feed on the nutrients in sapwood. The best place is a newly felled tree which, when you think about it, would be how the species managed before we came along!
So, the woodworm you've found might well have been living in the wood when you bought it. Now that the wood is indoors, it will be too dry to support future generations of the little pests.
Assuming that your workshop is warm and dry (<70% relative humidity - well ventilated), the chances of a future infestation is roughly zero - any emerging beetles will simply fly outside looking for a better place to mate and lay their eggs. In other words, the treatment was totally unnecessary, beyond offering you some peace of mind - like insurance.
There is another angle to this - the Health and Safety one. Personally, I don't trust chemicals. If woodworm treatments were completely safe, why do they keep changing them? Also, what is the effect of mixing old and new? No-one knows. Current treatments are based on Permethrin, which is highly toxic to aquatic life and cats (I'm a cat lover too).
When we bought this house, we were advised to treat all the timber, despite it being done about 7-8 years previously. Fortunately, they didn't make it a condition of the mortgage, and I decided to ignore the advice. My surveyor reckoned he'd seen evidence of woodworm in the loft, but when pressed, he couldn't remember exactly where he'd seen it. Oh yeah? You mean that standard paragraph wasn't removed from your template...
When I pulled down the ceiling in the cellar, there was a lot of evidence of wood-worm infestation in the joists. I will replace them eventually, but that has slipped down the priority list somewhat since uncovering major problems elsewhere. Once the ceiling was down, I opened up the front to back ventilation that had been previously blocked up by a former owner, and the relative humidity fell from >90% to between 50% and 80%, depending on the weather (it's always higher in summer). Clearly, since then, things have dried out a lot...
In the following spring, I saw a small number of adult beetles emerge from some of the joists. Hmm - shows how effective the previous woodworm treatment(s) had been
. That was in 2006 - since then, I haven't seen any. That was 6 years ago - comfortably longer than their life-cycle - the fact I've seen nothing since suggests that they've gone elsewhere.
Needless to say, in the 7 years I've been in this house, I've gone over it with a fine tooth-comb, and have found no other evidence of insect attack. Nothing whatsoever that would justify the advice to spray, despite having copies of the paperwork from the last company to treat the house back in the late 1990s, and despite what my surveyor said. Basically, this leaves me feeling hugely cynical about the timber specialist industry.
I normally trot out a link to Jeff Howell at times like this: http://www.askjeff.co.uk/woodworm.html
All the above said, I am fascinated at just how much they seem to like old radios. My thinking is that it's something to do with the glues holding the plywood together - and perhaps they especially like the birch that is commonly used. I'm planning to very carefully open up the panels on an old radio that was heavily treated by the former owner (therefore wasn't allowed in the house). I bought the radio for the chassis, and have no plans for the case beyond forensic examination...
All the best,
Mark
There is no doubt that the female will want to lay her eggs in the best place, which means reasonably moist sapwood. They can't survive in the dry, and they need to feed on the nutrients in sapwood. The best place is a newly felled tree which, when you think about it, would be how the species managed before we came along!
So, the woodworm you've found might well have been living in the wood when you bought it. Now that the wood is indoors, it will be too dry to support future generations of the little pests.
Assuming that your workshop is warm and dry (<70% relative humidity - well ventilated), the chances of a future infestation is roughly zero - any emerging beetles will simply fly outside looking for a better place to mate and lay their eggs. In other words, the treatment was totally unnecessary, beyond offering you some peace of mind - like insurance.
There is another angle to this - the Health and Safety one. Personally, I don't trust chemicals. If woodworm treatments were completely safe, why do they keep changing them? Also, what is the effect of mixing old and new? No-one knows. Current treatments are based on Permethrin, which is highly toxic to aquatic life and cats (I'm a cat lover too).
When we bought this house, we were advised to treat all the timber, despite it being done about 7-8 years previously. Fortunately, they didn't make it a condition of the mortgage, and I decided to ignore the advice. My surveyor reckoned he'd seen evidence of woodworm in the loft, but when pressed, he couldn't remember exactly where he'd seen it. Oh yeah? You mean that standard paragraph wasn't removed from your template...
When I pulled down the ceiling in the cellar, there was a lot of evidence of wood-worm infestation in the joists. I will replace them eventually, but that has slipped down the priority list somewhat since uncovering major problems elsewhere. Once the ceiling was down, I opened up the front to back ventilation that had been previously blocked up by a former owner, and the relative humidity fell from >90% to between 50% and 80%, depending on the weather (it's always higher in summer). Clearly, since then, things have dried out a lot...
In the following spring, I saw a small number of adult beetles emerge from some of the joists. Hmm - shows how effective the previous woodworm treatment(s) had been
. That was in 2006 - since then, I haven't seen any. That was 6 years ago - comfortably longer than their life-cycle - the fact I've seen nothing since suggests that they've gone elsewhere.Needless to say, in the 7 years I've been in this house, I've gone over it with a fine tooth-comb, and have found no other evidence of insect attack. Nothing whatsoever that would justify the advice to spray, despite having copies of the paperwork from the last company to treat the house back in the late 1990s, and despite what my surveyor said. Basically, this leaves me feeling hugely cynical about the timber specialist industry.
I normally trot out a link to Jeff Howell at times like this: http://www.askjeff.co.uk/woodworm.html
All the above said, I am fascinated at just how much they seem to like old radios. My thinking is that it's something to do with the glues holding the plywood together - and perhaps they especially like the birch that is commonly used. I'm planning to very carefully open up the panels on an old radio that was heavily treated by the former owner (therefore wasn't allowed in the house). I bought the radio for the chassis, and have no plans for the case beyond forensic examination...
All the best,
Mark
