wood worm and wet rot in loft

[philrosenberg]

Hi everyone
i've just been ripping out some old boarding in my loft to have my insulation redone (the boarding was like a very soft thin chipboard or something and couldn't suport a persons weight making it quite dangerous)

When I ripped it up I found a significant amount of woodworm in some of the ceiling joists. One joist in particular has holes all the way along its length and was rather crumbly. There was also sawdust next to the beam along its length, although i don't know how long it's been there as I imagine the boards over the top would have sheltered it from being disturbed.
I'm not sure what to do about it as there seems to be a lot of conflicting advice given. Some say treat with chemicals whereas others say that after a few years the timber is too dry for continued infestation, the treatment is toxic to humans and not very effective, plus the holes show that the beetles have left the wood so treating is like shutting the door after the horse bolted as it were. I'm also concerned about the toxicity of the treatment as the very bad beam is above the bedroom.

In addition I found a spot in the eaves with wet rot. It was just by the outlet for the bathroom extractor and the pipe had come away from its mounting plate so it was partially blowing the extracted air into the eaves. I've fixed the fan pipework but I'm curious to what i should use to treat the rot. Can anyone recomend a specific brand or product?

Cheers for any help
Phil

 

[masona]

Can you take a photo for better identification?

 

[philrosenberg]

Woodworm, the joist is 100x50mm which makes the holes about 1mm across. You can see the sawdust by the joint and the light area on the right is where i was able to just break the corner of the joist away with my fingers.

The rot is shown here slightly obscured by a spider web, the extractor pipe is just off shot to the right

 

[masona]

I really need to come and see it depending where it is on the structure, you will need an expert advice, from your photo they look like Power Post Beetles, more details here

Do not use any wood chemical treatments what so ever until you identified what the problem is and sadly they are companies out there given poor advice.

Edited above as I wrote it wrong

 

[philrosenberg]

If expert advice is needed then can you recommend anyone in the Milton Keynes area?

I have some spray treatment that I was given by a friend of my dad's who is a joiner. He says it should be safe within an hour but the more I read the more unsure I become.

If it helps then that one joist is as in the picture along it's full 3 metre length. Other joists nearby have some holes but none nearly so bad. I can't see any signs of infestation in the structural roof timbers, just some of the ceiling joists.

 

[JohnD]

It will be useful to poke the timbers to see how damaged they are. If bad they will need replacing.

With old insect attack, it is also useful to hoover up the dust and frass. Then if you see more you will know they are still active. But keep a sample as your expert may want to see it.

I use chemical preservatives but they will not kill grubs deep inside. They just stop new ones burrowing in. I have only ever seen furniture beetles, which are not as bad as yours.

Tip:
When prodding for damage, always use a flat-blade screwdriver, not a bradawl - then in future people will not see your round test hole and think it is an insect flight hole.

 

[philrosenberg]

Found Quite a good guide to woodworm identification at http://www.safeguardeurope.com/pdf_datasheets/woodworm_guide.pd
It says that Powder Post beatle attacks hardwood less than 15 years old. This is softwood about 50 years old.

I'll try hoovering and checking if more dust develops, do you know what timescales I should expect more dust? Days, weeks, months, only at flight time?

 

[masona]

It says that Powder Post beatle attacks hardwood less than 15 years old. This is softwood about 50 years old.

Your 1st photo doesn't look like softwood to me but can't really see close enough on the photo

 

[philrosenberg]

Sorry Masona, I guess it's not obvious from the photo, you also obviously didn't know how old it was.

A friend recommended that I paint it to cover the holes then see if new ones appear after the flight season. If I slosh a load of white emulsion over the wood then find new holes appear and treatment is needed then will the treatment penetrate emulsion or is there some other way I can tell if it's live?
I did get in touch with an expert in the area. He's a specialist rot and woodworm surveyor and does not treat himself so hopefully he wouldn't be biased. Unfortunately he wanted £255 + vat to come round and inspect then tell me in writing if my woodworm was live or not. If I can work it out myself I'd rather not shell out.

 

[masona]

Have a good read here //www.diynot.com/forums/viewtopic.php?t=67617&highlight=woodworm

Me being a carpenter, I always cut out all the bad wood and replace it because some parts could be the structure of the roof, I think your cheapest option would be to ask for a good recommended carpenter first

 

[JFC]

Do not use any wood chemical treatments what so ever

What makes you say this ?

 

[Softus]

Me being a carpenter, I always cut out all the bad wood and replace it because some parts could be the structure of the roof

This surprises me masona.

(a) I've seen very few roofs that lend themselves to sections of the structural timber being cut out and replaced. If you cut anything then the structure is weakened, and you can't insert some new timber and make it as strong as the original.

(b) Removing a joist, or rafter, or purlin, or wall plate, or whatever, is likely to be quite a difficult (i.e. expensive) exercise.

(c) Roof structures are over-engineered, for the very reason that they won't stay forever in the same pristine state as they were when new.

I think your cheapest option would be to ask for a good recommended carpenter first

I don't understand how this can be cheaper than chemical treatment, and, along with JFC, I don't understand your reason for recommending that chemicals are not used. After all, many of today's roofing timbers are pre-treated. Moreover, the information at that link you posted suggests that the use of a chemical is a fine and dandy thing to be doing.

 

[masona]

Removing a joist, or rafter, or purlin, or wall plate, or whatever, is likely to be quite a difficult (i.e. expensive) exercise.

Like I say, I need to see it, you cannot judge from one photo as they maybe more problem elsewhere and yes it can be very costly but there are other way of supporting the roof structure depending what the problem is and hence why I've mentioned a roof structural surverer is the best route.

Roof structures are over-engineered, for the very reason that they won't stay forever in the same pristine state as they were when new.

Not always, I have seen many roof where the owners taking out the collar beams or been tampered with I have also seen the roof rafters wallplate pushing outward including windows because of this. Another one I've seen is 2"x2" supporting the purlin onto the ceiling joists and not on the load bearing wall I have repair my roof purlin as it gave way in the middle because of the butt joint & not overlap From what I've seen, not all roof are over-engineered.

I think your cheapest option would be to ask for a good recommended carpenter first.
I don't understand how this can be cheaper than chemical treatment

Yes sorry , I meant the toxic chemicals to kill woodworm. The OP didn't want to pay out £255+vat and I said I think the cheapest option would be for a carpenter, the trouble is Softus nobody like paying out which is a shame because it's only a small price to pay considering for roof structure reports and I was trying to think maybe a good carpenter can help (?)

 

[masona]

Do not use any wood chemical treatments what so ever

What makes you say this ?

I meant until you identified what the problem is.

I have edited my post above

 

[JFC]

Well it's either the pixies drilling lot's of 1mm holes or he has woodworm . Quite a serious attack looking at the amount of flight holes . The wet rot doesn't look to bad and i think solving the problem ( a broken tile ?) and a chemical treatment will stop any spread of the rot . The wood worm however IMHO needs a full loft chemical treatment . Yes you should cut out all the infected timber with both types of rot but looking at the woodworm attack and flight holes i would expect the whole loft is infested with them or will be some time soon . Chemical treatment is the best way for you to go IMHO .