Help! Do we have Woodworm?

[harriesg]

We live in a semi-detached Victorian property (approx. 1890) and have just taken up the carpet in our bedroom to expose the floorboards. On the whole they are in good condition, but a few of them have obvious woodworm flight holes.

The concern we have is how can we tell if they are fresh or old? We have read to look for fresh sawdust like collections around the holes, but are unable to see any at the moment (although we have only just finished sanding the floor in preparation for varnish - Ronseal Diamond Hard). There are also a couple of floorboards that can be taken up (to expose pipework and electrics), which don't have any signs of woodworm on the underside - which we had also read was something to look for.

We have just bought new furniture for the room, which is teak wood and we really don't want to introduce it to a room with woodworm. Is this something we should be worried about?

We were just going to treat it anyway with Cuprinal Woodworm killer, but have since read not to do this unless it's definitely still active.

We would be grateful for any thoughts on this. Thank you.

 

[biffvernon]

The holes are probably ancient. If there are active woodworm they will start emerging over the next few weeks as the weather warms up. You will find the little piles of frass, the finely powdered ex-floorboard. Unless you see this, it's safest to assume the woodworm died out many years ago. Anyway they won't like teak, nasty foreign food. Woodworm prefer rough and damp pine. Cuprinol is also bad for your health.

 

[harriesg]

Thanks for that.

Would we be best leaving it a couple of weeks to be certain they're not active before applying the varnish then or can it be treated if we apply the varnish and then find they're still active?

 

[Paul Hopper]

Hi

Woodworm is usually one or more of three or four types
1 Common furniture beetle... (actually an insect that you can find in most hedgerows at this time of year. its flight season is May to September and its distinguishing exit holes are crisp circular; holes, 2mm or so round. the little so and so's like softwood, and are not often found in hardwoods.(they do not seem to like it much!)
if you have an active infestation it will become clear if you monitor it for a few weeks, frass (dust) exit holes and sometimes the actual tiny beetle itself. They do not live long in flight or mature stage, it is the larval stage that munches your wood. they tend to prefer softwood or older ply (something to do with the older adhesives used pre and post war
if you treat your furniture with teak oil or such they cannot lay eggs so cannot spread. There are treatments (see SPAB) which are much less invasive than Cup***nol. If it turns out really bad then cut out the affected board or boards and replace if you can generally though a careful treatment with an SPAB preservative will see them sorted.
2 Death Watch Beetle (so called because it is claimed you can hear them in old church timbers in the silence of the night (ooh Scary!) I've never heard them though in 30 odd years. Seriously though they only affect old hardwood and leave much larger flight holes.Unless, like ours, your house has larger section old hardwood frames in construction or in a roof void you will not have problems (they seem to need a lot of years (200+) to show up. The wood will become very friable and the infestation is very distinctive, SPAB will recommend what to do.
3 Wood Boring Weevil (WBW) you won't see this chap but you will see where its been, Affects damp timber (not sopping wet, but for instance, in a board or joist end that has been close or next to a damp wall plate or set into wet stone or brickwork. Rarely will you see "flight holes" but you will see surface striations in the wood where the tunnels have worn through to the surface, especially if recently sanded like areas where condensation occurs (around a porcelain loo base for instance but generally more associated with the wet rots than with wood borers as such.
Having said all this I have just spotted fresh flight holes in the softwood boards of our upstairs loo, I shall go against all that I preach here and treat them with some Protim wood preservative which I have had for years, Not done today..SPAB will have a fit! but it works!

Do not worry too much, keep an eye on them and treat in accordance with SPAB practice. Beware the dreaded Woodworm Surveyor! many are super and careful in their surveys but their treatments can be very harsh and smell for ever.Woodworm is part of owning an older house, they are literally part of the history so treat them as you can, monitor them and relax abit.
I think others will add to this post with more ideas on the subject.

Paul Hopper

 

[Matt Green]

Woodworm is usually one or more of three or four types
1 Common furniture beetle... (actually an insect that you can find in most hedgerows at this time of year. its flight season is May to September and its distinguishing exit holes are crisp circular; holes, 2mm or so round. the little so and so's like softwood, and are not often found in hardwoods.(they do not seem to like it much!)

You find them in the outer, sapwood edges of hardwoods. It's not uncommon to see furniture beetles and deathwatch alongside each other in oak sapwood. They'll attack both hardwoods and softwoods that are wet. A water source or humidity that will raise timber moisture content over 18% is cause for concern.

2 Death Watch Beetle (so called because it is claimed you can hear them in old church timbers in the silence of the night (ooh Scary!) I've never heard them though in 30 odd years. Seriously though they only affect old hardwood and leave much larger flight holes.

They USUALLY attack hardwoods. They are quite capable of damaging softwoods- you just don't see it as often.

You can hear them tapping too if you survey during a hot day between April and June. You need a quiet building though.

Unless, like ours, your house has larger section old hardwood frames in construction or in a roof void you will not have problems (they seem to need a lot of years (200+) to show up. The wood will become very friable and the infestation is very distinctive, SPAB will recommend what to do.

Whilst there may be a change in the chemistry of oak over hundreds of years that reduces its durability- there's not much in the way of proof. Deathwatch will attack the sapwood of hardwoods regardless of age or diameter of timber. If the timber gets wet, the heartwood extractives that confer durability are removed/broken down and the risk of atck goes up.

Permthrin pastes in a gel carrier fluid aplied at the focus of atack has the best results- once the source of water has been isolated and attended to.

3 Wood Boring Weevil (WBW) you won't see this chap but you will see where its been,

you can see them- you just have to pull the wood apart a bit. The commonest species' are approx 2x5mm including legspan.

Affects damp timber (not sopping wet, but for instance, in a board or joist end that has been close or next to a damp wall plate or set into wet stone or brickwork. Rarely will you see "flight holes" but you will see surface striations in the wood where the tunnels have worn through to the surface,

What you've described are, in fact the flight holes- they just dont cut circular exits in the surface of the timber. And yes you do find them where timber has a high likelihood of decay from fungi due to groundwater ingress. Again, the timber has to be wet.

(around a porcelain loo base for instance but generally more associated with the wet rots than with wood borers as such.

Men are to blame. The raised Nitrogen and water content around the base of the loo will render it more susceptible to attack. You see the same sort of thing where bats have urinated over church beams.

I think others will add to this post with more ideas on the subject.

Certainly. The big thing is to understand that these insects will only affect the sapwood edges unless the timber is very wet and they require a raised moisture content to even attack the sapwood. Beware impervious underlays and such like.

In sort- there's nothing to worry about in this case.


Matt Green

 

[Penners]

Harriesg

This is a good time of year to find out whether your woodworm is active or not, and there's a pretty easy way to find out.

Buy yourself some Spray Mount aerosol glue from an art shop, and get hold of some tissue paper. Spray the glue very lightly on to the paper and after letting it dry for about two minutes, press it down over an area where there are lots of flight holes.

The beetles should be emerging and flying pretty soon now (if they haven't already) and they will puncture your tissue paper. So in a few weeks time, if you haven;t got any little hole sin the paper, you can be fairly confident that the infestation is old and inactive.

Spray Mount is a peel-off glue, so it should be easy to get the paper off the floorboards, once your scientific experiment is finished.

 

[Paul Hopper]

Hi Matt

A fellow nut on wood boring creatures then!

What I said about Death Watch not being as loud as all that merely means that the Churches I surveyed in the past were clearly too noisy to produce a result.. certainly collegues have told me of their experiences, its just that I have'nt heard them.
As for your comments, I respect your views, thanks for correcting and adding more detail to me post.especially on the question of sapwood attack. I did know but when u type these posts I know I often think about it for not long enough or miss a bit of important information. sorry!

Paul Hopper

 

[PC]

Adding to what others have already said,

Its quite possible that it is an old infestation in floorboards.

However life cycle of CFB around 2-3 years so dont assume that its dead because nothing emmerges this year, you may have to monitor for longer period of time to be absolutly sure.

What ever happens dont treat timbers unless completely necessary.

PC

 

[Moo]

SPRAYMOUNT WARNING -

There are two types of Spraymount.

The one you want is Repositional

The other one isn't: Once it's stuck, it's stuck for good, and you will spend many hours, cursing Penners as you go, scraping off the shreds of tissue paper.

So - be careful to read what it says on the tin.

 

[harriesg]

Thank you all for these responses. They are much appreciated and we have now decided not to treat the "woodworm". We were also due to have a professional company come in and take a look, but I am getting the impression that they will just tell us we require treatment so have cancelled them.

Could someone let us know whether we would be best leaving it a couple of weeks to be certain they're not active before applying the varnish or can it be treated if we apply the varnish and then find they're still active?

Thanks

 

[Ian Bond]

Hi

Just thought I'd ask the question - is varnish the best thing to finish a period floor?

I'm in the process of repairing my pine floors. They do not appear to have any modern varnishes put on. I think they've been covered in carpets for many decades.

Most of the period propery books (Hugh Lander et al) I've read so far advise against varnishing floors, saying that it hampers the development of the patina, is hard to maintain etc.

Instead I have contemplated leaving the floor completely unfinished, or wax polishing.

Has anyone had success with floor varnish?

Thanks

Ian

 

[harriesg]

Ian

We would be interested to know the views of those more experienced on this as well, as we would like to do what's best for the floor and our house.

 

[Penners]

Moo

SPRAYMOUNT WARNING

A fair point, and well worth mentioning. However, I think that the permanent spray glue that you're thinking of is Photo Mount. Proper 3M Spray Mount is a repositionable (ie: peelable) glue. Provided it's used very lightly, as I said, it shouldn't be a problem.

 

[Ian Bond]

Hi

I don't want to put you off varnishing - it might turn out to be the best treatment for the floor?

But I didn't want to wait until after you'd done it to chuck a spanner in the works by asking the question. I've been there myself and ended up wishing I hadn't just done something!

I've seen some varnished floors that have gone orangey in colour, but I'm not sure if that was just down to to poor quality varnish.

Ian

 

[Matt Green]

You won't get any treatment through a layer of varnish.

If this is a first floor room, at teh edge of a floorboard with no obvious source of water, I would simply ignore them.

 

[harriesg]

Ian

We're glad you have asked the question as we have no experience of doing this, so if people have alternative suggestions we'll take them on board.

 

[NT]

Most period houses have woodworm damage, perhaps because the wood went in with relatively high RH, and due to no heating took some while to dry out. As long as the holing isnt severe its of no consequence beyond cosmetic.

One of the problems with sanding floors is that it does sometimes reveal a maze of tunnels under the surface.

There is no need to do anything unless you have a particular reason to believe there is a problem. Spotting the holes in your historic floorboards is not really reason to think theres a problem, most period properties in Britain will have old wormholes.


NT

 

[harriesg]

Thank you for putting my mind at rest.