Question for outdoor wood-fanciers

Hello all,
I have an all-wooden 1st floor balcony, about 6x4 ft, where the balcony floor consists of about 10 narrow wooden planks (separated by thin gaps, not tongue-and-groove) supported underneath by 4 (much fatter) joists that are in fact extensions to the joists supporting the 1st floor interior. Obviously, the joists are at right-angles to the narrow planks, which in turn are parallel to the wall of the house.
Despite trying to keep everything covered in sadolin, the narrow planks are mostly rotten. One of the joists is appears partly rotten, but only along its outer edge, and a carpenter chap (who has since become uncontactable) assures me that this was originally tree sap, and the "rot" isn't really rot, it's just insect infestation of where the sap was, and the rest of the joist is not in any danger of rotting.
So here are a couple of questions for all you woody folk out there:
1. Using a screwdriver, I have vigorously scraped away the infested part of the joist, leaving about 95% of the original. Is it now just sufficient to sadolin over the exposed surface, or should I treat it first with anti-insect stuff?
2. What type of wood should I replace the narrow planks with? Because it was so fiddly to sadolin between them (because of the narrow gaps) ideally I want fewer but wider planks, also perhaps with a "camber" like a road so that rainwater runs off 'em (the old narrow planks had no camber). Is this possible?
Thanks a bunch, Richard
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Have a web search for "Timber Decking Tips" and it should give you a few goods hits and furnish you with more than enough details on how to tackle this type of job.
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Iroko or teak for the decking - well spaced to avoid water entrapment. Before laying machine bevels on the top of joists to shed water and if poss also machine drip grooves on underside so that water is shed at the edges and doesn't collect underneath. Lay the boards on about 6mm brass copper or stainless spacers, washers etc so that there is minimal capillary action and water retention at the wood junction, and fix with copper nails or brass screws. Copper best - copper salts are anti-fungal.
cheers
Jacob
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You need to use pressure treated timber unless you're going for something exotic (and expensive). Make sure you soak the cut ends in preservative also for a few minutes - stand them upright in a tin or tray etc.
--
*A conclusion is the place where you got tired of thinking *

Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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Richard Clay wrote:

Treat it with a good anti fungal/incect/wet/dry rot solution before you seal it in...

Teak decking from a scrapped pontoon would be my recommendation, my conservatory floor came that way, the stringers/joists may need replacing, but the plankings still fine....
Niel.
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