Does decking hardwood rot?

[borismilo]

I am about to put in an order for decking board but am stuck on the decision about what to buy. I am going to use Australian hardwood and more than likely I will be using Ironbark. Where the issue comes in is that I have found some timber that has a different profile - grove underneath allegedly to stop cupping and tapered sides to allow for self cleaning. There are lots of compelling arguments why the features would help, but I haven't really heard any horror stories about decks being built using standard pencil rounded Ironbark that suffer from the problems allegedly addressed by this product.

The timber comes with a dressed face or a rough sawn/sanded face. The recommendation is that the rough sawn/sanded face be used in fully exposed places because it performs better. This makes little logical sense since rough sawn, even when sanded, has a larger surface area and more capacity to trap water - only negligible I would imagine, but still a greater capacity. It does give greater slip resistance but I don't intend doing a waltz on my deck in the rain anyway.

I have deliberately left the product name out of this because I googled the name and the only references that came up to the timber were the manufacturer or suppliers - ie sellers, not users. I am sure there view would be somewhat different to mine.

Does anyone have comments about Ironbark's performance in a fully exposed situation? (My deck will have a roof over about 3/4 of it but the exposed part is what I am worrying about).

Thanks
Boris

[David L]

Hardwood will rot eventually if exposed to the weather. We had to replace our 20 year old back landing in 1985 and when we replaced it with a deck 18 years later some of the flooring was showing signs of deterioration.
Keep in mind this would have been agrivated if the timber had spent concidreable time in the shade prolonging drying.
I can not comment on the sanded finish as opposed to dressed.

David

[glock40sw]

Kiln dried Grey Ironbark will last longer than You & I. :D
Just oil it every year with deck oil.:2tsup:

[Larry McCully]

I have seen 200 year old piers in the creek and still going strong. :U
But on your deck it is different. When your deck is capturing moisture and not drying out it will rot.
All wood has the potential for rotting, as it contains a certain amount of moisture. If moisture content is below 20 percent, rot typically isn't a concern. Anything over this provides a potential breeding ground for fungi, which is what causes wood rot.
Moisture is just one thing that fungi need to survive. They also need the following:

Favorable temperatures. Anything in the 40°F to 100°F range will do.
Oxygen.
A food source. The fungi that attack wood prefer carbohydrates in the form of cellulose and lignin.
Wood is made up of cellulose and lignin, and the other factors are pretty hard to control, so fungi abatement efforts generally focus on the one variable—moisture—that we can do something about.
Make sure that there are no causes for ponding.
During the installation process, it is best to coat all surfaces of the timber with a penertrating anti fungi product. Feast watson, cabots and others have a product for the purpose. Your deck will last a lifetime if cared for. regular coating (every 12 months) will keep you deck looking good.

[lbgking]

Your deck will last a lifetime if cared for. regular coating (every 12 months) will keep you deck looking good.

Flood now offer a 2 year warranty with their Spa & Deck range. While it is a little more expensive it is worth it.

[Bodgy]

Flood now offer a 2 year warranty with their Spa & Deck range. While it is a little more expensive it is worth it.

One would hope for somewhat longer than 2 years life from a deck, would one not?

[borismilo]

Thanks for the ideas. I went over to my neighbour's place to have a look at their deck to see what sort of issues they had. From the look of it, nothing was trapped between the deck boards except over the joists. They did have a major problems where the ends of the shorter boards were joined over joists. It looks like it was rotting a bit so I think liveral application of sealer will be needed. I will also try and put all my long boards in the exposed areas and keep the oil up to it. I ended up ordering Grey Ironbark and am looking forward to drilling 800+ holes and banging in nails. Should be fun!

Cheers,
Boris

[Larry McCully]

If the smaller boards are breaking down, then most likly at the construction stage the ends were not sealled with a product like creosote. The end grain will suck up water and stays wet longer , then the rot sets in. Just for your info, ripple deck (the profile that has multi groves on one side) is so that air passes between the deck and the joist , it keeps the junction between the two dryer. The ripples are laid facing the joist.

[strangerep]

[...] I ended up ordering Grey Ironbark and am looking forward to drilling 800+ holes and banging in nails. [...]

Grey ironbark is an excellent choice. It's one of the most durable timbers
you can buy in Australia.

See previous post "Timber Species Properties Relevant to Decks"
for more detailed info:

http://www.woodworkforums.ubeaut.com.au/showpost.php?p=523252&postcount=1

If you're going to the trouble of pre-drilling all those holes, use screws instead
of nails. They hold much better than nails (proven in CSIRO tests).
Use square-drive 10g type-17 stainless steel 50mm or longer, and don't
make the pilot hole any wider than you really need.

Study lots of the previous threads about weathering/finishing before
deciding on coatings, and when/how to apply. (Do not pre-coat the tops
of the boards (but pre-sealing the end grain at joins that you can't access afterwards is probably helpful).