On 8 Feb, 21:57, wrote:
Any thoughts on what would be the best preserving stuff
to paint a shed with? It's shiplap construction, and the
wood has a sort of green tinge to it, so I think it was
tanalised or similar before construction. Ideally the finish
would not be too dark, a sort of golden syrup colour
woulld be perfect. Preferably something that would last
a few years before I have to squeeze between the shed
and the fence again!

Thanks for any thoughts.

Danny

Dear Danny
Is you address a coincidence? (smile).. on to the answer
If your shed (empahasis - can't use capitals any more!) ...is...
tanlalised then you do not need to preserve it. You need to find out
for sure. Look at the timber inside closely and see if it has the
green (or in later years possibly brown) tinge. To differentiate
between true water-borne vacuum impregnation and a later application
of a treatment fluid to get such a colour effect you will need to
"sacrifice" a small section of timber near the end grain of a piece
being investigated. go for a piece of treated end grain and cut a
longitudial sectioin out, say 1 mm thick , a 20 to 50 mm long and 5
to 10 mm wide such that you can see the whole of the cross section of
the end grain eithe tangentially or longitudinally. This will tell you
for sure (almost) if it has been treated under pressure as you will
see the treatment colour a long way up the end grain which would not
be the case with a brush application. If someone has done an immersion
treatment that may fool you but such a treatment is not likely with a
shed.
So assume you find it ...is... tanalised then all you need is a
decorative finish. Psuedo-creosote, (it is bound to be against COPR to
sell you real creosote - Elfin S again!) or much better Saddolins
medium build Water Repellant Preservative Stains.
If it has not been treated and you think you need to treat it - decide
why. Only consider treating areas at risk - sole plates - end grain
exposed etc etc and consider physical means first ( eg isolating sole
plates with a dpm). Were you a professional contractor - you would be
obliged to take this route under the Coshh regs. As an amateur you can
do virtually what you like provided you follow the instructions on the
tin.
I recommend (as posted by others) an OS based fungicide and
application on a hot summers day when a cold night is forecast. If you
can apply several coats - so much the better. Once the active
ingredient is in the timber proceed to protect with a WRPS as
described above.
Hope the shed is worth it!
Chris G