Washing new Jarrah before finishing??

A rep told me in Bunnys (not a Bunnys salesperson) that I'd have to wash down my new Jarrah with a timber 'refresher' mix (Ox and hydrochloric acid mix) before finishing so that I would not end up with the tannin leaching to the top in ugly black spots if it got any water on it. It's vaguely undercover, but Melbourne rain can get fairly horizontal on occassion...

1. Is this fair advice or a sales pitch?
2. I voiced my worry that the timber might distort (bow etc), and she added that if kiln dried properly it would not. Any thoughts here? And how the heck does one figure if ones wood had been kiln dried 'correctly'??

Basically trying to work out whether I should take her advice. I've done other decks etc and never heard about this. Then again, I have not worked with Jarrah before. Can anyone share some experience? Thanks

if the timber you brought is in perfect condition (which it should be) then no, you don't have to wash it down.just make sure you don't leave it exposed to harsh weather for to long after you lay your deck.you can seal it with an all weather oil sealer or if you prefer a smooth shinny finish cabbots cabathane will give you a fantastic finish.be sure to use their outdoor product though.

I built a deck out of recycled timber and had that exact problem. I laid the decking and a day or two later I oiled the deck with a wattyl decking oil. About a week or two later, I started seeing all this black spot appear on the top of the boards. It got progressively worse and really looked like crap.

I made some enquiries and the answer from bunnings was to sand back the whole deck (and, coincidently they could rent me a sander) and then wash down with a mix of oxalic acid stuff. In the end I ignored Bunnings advice and souped up the mix a bit more by making the solution stronger (not diluting as much). I scrubbed it down, left it for 20 mins and then hosed it off. Almost all the spots were gone.

The spots came back again once more, so I did the same thing again. Now its been 12 months without any problems.

My suggestion is to take their advice - I didn't have any problems with distortions, but I did wash it after I had laid it. You can just buy a deck cleaning product to do the cleaning.

Trav