What stain, preserver, paint should I use on my tanalised timber obsy?

[Darren Naughton]

Hi everyone.

I have recently had a shed built 5m x 5m square. It is made from shiplap tanalised treated wood, heres the issue I have had a small leak on one side from driving rain pushing it's way through the small gaps in the interlocking joints. Unfortunately I am no longer able to contact the constructor of the shed so I'm at a loss of what to do. I have used a multi purpose sealant from a gun tube at the ends of the lengths to try stop the water gaining entry into the corners were the water is leaking internally. I was considering going down each length and filling it with something to stop the water coming through but this will not only cost a fortune but look unsightly. 

Is there a tantalising paint that I can use to seal the gaps and also aid in reflecting water but I know this is probably not possable a paint that will also allow the wood to breathe as i dont want internal condensation. 

The wood is definitely tanalised it has a light green tinge to it and 4 months old.

Any help on this would be very much appreciated.

Thanks 

Mr D Naughton 

[bottletopburly]

Any Solvent  based preservative , you can get green , do not use water based preservatives as these tend to seal the wood causing wood to eventually rot imo 

[Bizibilder]

I used shed paint on my own observatory - Three coats as specified with the paint and then a coat every three years.  It had it first "three year" coat last year and looks as good as new.

[old_eyes]

Someone on here recommended Jotun Visir preservative and Jotun Demidekk paint. Designed for Scandinavian winters and generally reckoned to be bombproof. You can see it here https://www.thepaintshed.com/catalogsearch/result/?q=demidekk

More expensive thatn other solutions, but in the grand scheme of observatory construction not a big issue. I found it easy to use and gives a good finish.It has only been on 6 months so I can't persoanlly speak to reliability but others swear by it.

[laser_jock99]

Avoid the water based, acrylic type 'wood preservers' at all costs.