N WALES - help -BORON wood treatment needed

[welshchapel]

I am renovating  a welsh chapel.

Some of joists were UNTREATED (as i have multiple chemical allergys) and developed DRY ROT in 8 weeks.

Is there a builder/ carpenter near PWllheli (N Wales) that can help me treat remaining wood WITH BORON.

and fit new joists and treat WITH BORON
HELP IM DESPERATE - WHOLE PROJECT HAS COME TO STANDSTILL

AND DOES ANYONE KNOW WHERE I CAN BUY WOOD THAT HAS BEEN TREATED WITH BORON ??
THANKS

[Geoff Stow]

I think you should try to find out why the dry rot appeared. generally there is no need to treat joists so it is possible that the detailing needs to be looked at. It may be worth contact CAT to see if they have any specialists known to them. bprn is easy to use and you can insert pellets but they do need to be replaced. It may be worth contacting the manufacturers.

Geoff

[welshchapel]

thanx Geoff

Carpenter claims wood was wet when he fitted it so the dry rot must have been in the wood when supplied.  He says he didnt see any because it was wet.  What do you think??

So i have now paid for wood, fitting and removal - and still have no joists in that area.

Other joists fitted few months earlier in same building but different area are still ok

But some others fitted after dry rot ones removed are going darker and smell musty/mildewy?? 

I contacted CAT and they told me to try AECB.   I

there is no heating in chapel - could this cause joists to go mildewy??

there are no leaks from roof but it has no insulation so it is very damp on top ceiling.

chapel is large 75' x 25' so impossible to heat at moment.

[Peter Wilkinson]

Geoff has asked me to comment on this dry rot problem you are having.

It is not clear from the information given to date where the joists are (ceiling joists or ground floor floor joists). The location of the joists in relation to damp conditions is a factor. Geoff is quite right to say that once replaced & damp is eliminated & dry, ventilated conditions are created, then dry rot will not reoccur.

Dry rot occurs following wet rot. If the wet rot is not fully removed & all timber debris, fragments of old rotten joists etc are not removed then dry rot may very well occur. Dry rot spores are in the atmosphere all the time & in all locations & require the right environmental conditions to germinate. So it is quite possible that dry rot will occur following remedial works if the conditions are right & wet rot fragments are remaining on site. If the fabric of the building is still wet (including joists brought on to site) & then fitted into a poorly ventilated space, then yes, dry rot can occur as the fabric & joists dry out but old wet rot material is allowed to remain.

It is imperative that the areas affected by wet rot or previous dry rot are cleared of all rotten material. This is not an easy job to do thoroughtly, so requires a full understanding of the implications by who ever is carrying out the cleaning out work of the consiquesnces. One can see why some contractors turn to harmful chemicals as an insurance against their opperatives.

Create a dry & ventilated space for joists out side of the insulated zone & this should stop dry rot occuring. Even in insulated zone it is important to keep building fabric dry & ventilated, so avoid condensation issues (heat/insualtion & ventilation).

Using Boron treatment should be a last resort & as really means that there is no confidence that the right conditions can be created. Thsi really is a failure of the building renovation process & can be avoided.   

[Duncan Roberts]

Geoff asked me to reply as well & I would back up Peter's remarks that it is probably the original building that is the cause of the trouble rather than something you can fix by treating the timbers. Although the idea of installing wet timber joists makes me worry about your carpenter ( or did you supply the offending material ? ).

The notion of renovating a chapel in Wales makes me think of dripping stonework half built into a shady hill side. If this in any way describes your project then you need to address the means by which you are going to to keep all that welsh water out of your building. If the external ground level is higher than the bottoms of the joists at any point you are going to have to create new drainage channels & ventilation spaces to keep your timbers dry. Are the affected joists built into the walls so that the end grain is in contact with any masonry, if so this needs addressing asap ?

I tried using borax candles once but in absorbing moisture they expanded & split the wood !

Finally, when you do get to the point of drying out the the building don't use a calor gas heater as this will give out huge amounts of water vapour ( which kind of defeats the object ).

 

[Chris Herring]

All good advice.  On the use of boron, the most effective treatment would be a glycol borate (disodium octaborate tetrahydrate in a glycol carrier).  These have been shown to penetrate even dry (16% mc timber) up to 40 mm, giving really significant protection.  This contrasts with 'conventional treatments' which have much lower penetration rates.  This can be a useful addition to the sensible measures above, or where these can't be completely implemented.  With MCS you need to be wary of everything introduced into the building.  The boron salt should not be a problem and it is not so likely that you will react to the glycol.  Or you could use a water based solution, although this will be less effective.