Woodworm above lath & plaster in attic

[Flat Eric]

Rennovating my attic and have discovered where visible there appears to be a moderate degree of fresh (new holes) woodworm infestation in the roof timbers. I had the floor boards and joists treated last May after I discovered localised fresh activity there and am fairly satisfied this killed these active beetles.

However the activity in the roof timbers is a new discovery. I noticed that just one visible section of spar had fresh (ie from last Summer) signs a few weeks ago. However most of the roof timbers are concealed by the lath and plaster of the ceiling and I have no idea what lurks behind most of it. Recently erecting a new section of stud wall led me to make a rough hole in the L&P and the laths and spar timber I uncovered didn't look too good wrt woodworm.

Here are my options:

1] I pull all the lath and plaster off, get the whole roof inspected and treated, prior to insulating and reboarding, Undesirable due to v nasty mess - taken an entire L&P ceiling down before - not something I'd like to repeat really

2] Remove lateral strips of the L&P about 15cm wide and 1m apart - sufficient to insert the spray lance and get the roof spars treated 'blind'. This was the technique that was employed for the floor treatment. I removed floor boards at 1m intervals, the full width of the attic, to spray the underside of the floor boards and the joists. Then insulate and overboard ontop of the remainder of the L&P

3] Treat using the Rentokil fogging technique - anyone got any first-hand experience of this? May be just make one cut into the L&P at the Apex to allow tube/lance to be inserted and blow down each tunnel formed by the spars, L&P and roof tiles. Can also get access at the bottom of these voids from the eaves area of the attic front and back, so could blow the 'fog' up as well

Any advice/thoughts much appreciated

[bigcat]

You illustrate perfectly how to turn a simple problem into a big headache with lots of trouble and expense, ie by using non-effective methods to treat it.

Chemical treatment of woodworm is no solution. Simply understand the cause, and remove it. Woodworm attack only damp timber, they dont infest when the wood's dry. Therefore you have a leak that needs fixing.

As youve found, chemical treatments dont solve the problem.

NT

[Chris Bacon]

3) seems your best bet if you want to avoid pulling down the P&L, but I don't understand why you can't access the ceiling above the P&L. Also, with 3), you will be treating everything, not just the timber. Why can't you access the timbers?

[Andy Dingley]

For most values of woodworm and UK locations. But have an entomologist study the holes, and ideally a dead bug, before assuming this is a guaranteed fix. There are UK species that will eat dry hardwoods, and a few that will have dry softwoods too. Although if you find a leak, obviously fix that anyway.

Can anyone suggest a _UK_useful_ guide to the entomology of common timber pests ? I've got a great one for the USA, but termites just aren't my main local priority.

[Anna Kettle]

Yes _the_ book is Timber Decay in Buildings: The Conservation Approach to Treatment CBD Price: £40.00 Author(s): Ridout, Brian

He is loved by English Heritage & co cos his approach is not the "remove everything for miles around and poison everything else" technique. I think they gave him a grant to write the book

I heard him give a talk once and he knows his stuff

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Lobster]

How about

?

David

[Flat Eric]

Coz its an attic and the timbers are sandwiched between the roof slates and the lath & plaster

[Flat Eric]

With respect I think the checmical treatment has worked on the areas it was applied - the most infested area incedentally was bone dry

[Chris Bacon]

I thought that was what you were driving at... there may be some benefit in removing the P&L, you can as you said check and treat the timbers, and insulate... "work creation for the inventive". I hope your slates are well attached! You might, as you say, be able to remove strips and get the lance in, I should think that would wet the timber more effectively than "fogging", certainly it would not treat so much of the plaster/slates... you should get an "air helmet" if you're going to remove the P&L, it's much much better than a mask.

[Flat Eric]

mmm sounds interesting Anna. To be honest I hadn't really a non-checmical option - which you can see from my initial post. However, I am ALL in favour of this in principle, if there are alternative proven non-nasty techniques.

However, the book is a bit expensive though for a one-off reference. I could do with trying to locate a copy to borrow for a bit. Any ideas?

[nick smith]

I have often wondered if it would be worth trying killing the things with microwave energy. Naturally there are hazards ! e.g. setting fire to something inaccessible or reflected energy going somewhere it shouldn't.

Anyway, how about defeating the door switch, opening the door, holding it under the lath and plaster ceiling and cooking the little darlings ?

Naturally, its a bit heavy, so you may prefer a method of holding it up, not to mention being a little distance away from where the "action" is.

For a more meaningful weapon, I presume a magnetron could be fixed on the end of a waveguide and used as a "wand" to project the radiation in a more focussed manner at the "area of interest".

I guess someone has done this before, so what are the "ins and outs" of this then ?

Nick

[Andy Dingley]

Insects (cockroaches) less than 3/4" long are effectively immune to microwaves. DAMHIKT.

[Anna Kettle]

He's not totally non-chemical, says there is a time and place for it but not every time and every place

I got mine from the library

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Lobster]

Hey, this is the internet - of course they have!

't try this at home folks... David