Hardwood for external decking structure

[jackruss]

Sorry if this is a silly question but...

I'm planning to build a small deck that is exposed to the weather ( no cover).

I'm planing on using bog standard F11-14 Hardwood RS instead of treated pine for the bearers and joists.

Is this suitable for exterior use without any treatment? I really don't want to paint it!

The top deck will be cypress pine 90x 19

Your advise would be greatly appreciated.

JR

[bitingmidge]

Untreated is fine with the following caveats:

1) Prime all joints (and that means the tops of the joists under the floor boards) with a heavy oil based primer. Make sure there are no unprimed places which will remain moist after rain, hosing or heavy dew.

2) Be prepared to put up with stains on anything below as the tannin leaches out. This includes walls and any surface water will run over.

3) Any other advice you get is probably correct, but not as correct as the above!

4) It's always a bit neater and will help prevent splintering if you arris the timber before doing any of the above.

Cheers,

P

[nt900]

<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1:country-region w:st="on"><st1lace w:st="on">Cyprus</st1lace></st1:country-region> is a nice choice for the top deck. I never used cypress before I built my rear deck and boardwalk, and it's a winner. I used 130 x 28 boards (rounded corners on the top side) for a real chunky look. I love it. By the way, I used treated pine for the bearers (35ish x about 250ish) and joists. But painted the sides to match the house. The cypress deck I just use decking oil on. But the dogs dirty feet make a bit of a mess of it especially the under cover sections that don't get the direct rain.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

[capedcrusader]

Is this suitable for exterior use without any treatment? I really don't want to paint it! JR

You should use a high durability species (class 1 or 2) - I dont know what class standard hwd is in Sydneyv though.

[MarkV]

Good to see someone using hardwood instead of that treated pine CRAP. By the time the hardwood is rotted away the treated pine would have been replaced many times over. For my money treated pine is soft toxic splitting rubbish and it's use should be avoided at all costs. Millions of hardwood fenceposts can't be wrong.

[Thommo]

Hi Jackruss, do your self a favour and use jarrah or merbu for the top and not pine.

Have done a few deckings and found that the pine does not last last and cracks and breaks, spend a little bit more and get the jarrah or merbu, you will not be disapointed in ther long run.

Good luck with it all

Thommo

[Theva]

Jackruss,

Common hardwood species available in Sydney are blackbutt (mostly, from north) and stringybark (some from south).

Are you planing to use white cypress as decking? It is class one but have the tendency to split when nailing.


Regards,

Theva

[martinm]

Hi Jackruss,
I built a deck a couple of years ago using treated pine for bearers and joists, and used a hardwood for the decking. I think the hardwood was called "northern box" (or thats what they told me it was..). It looks very similar to jarrah, deep red/brown colour. I painted the treated pine with a pigmented oil-based type stuff called "raincoat". I think it works by absorbing the hydrocarben solvent rather than leaving a coat like normal paint does when its dried. Advantage is scratching surface doesnt matter. it also comes in a variety of tint colours. The deck was painted with just normal decking oil (contains UV stabilisers etc). Looks a treat and havent had any problems with boards splitting or lifting up (yet!). Note you have to pre-drill the hardwood boards to stop them splitting when you nail them in.
cheers,
martin

[julianx]

I always use ironbark decking in exposed situations it's class 1. cypress splits and shrinks and is generally a pain to work with.I usually prime all the frame before the decking goes down too if the deck has no roof.

[jackruss]

Have already bought the cypress boards ( price too good to turn down $1.80 l/m)

Will have to confirm the class of the hardwood but looks like priming it is a must (

Ah well, Thanks all for you advice.

JR

[glock40sw]

G'day All.
Please be aware that durability 1 & 2 species that are not treated and not sap free, will still rot at the sapwood.
sapwood is not rated at the same durablility as the truewood.
I built my rear deck with "TAN e" treated Spotted Gum for the posts. bearers & joists.
Decking was "Tan e" treated Spotted Gum 85x19 Pencil round.
This was 7 years ago and it still looks great.
Hooroo
Regards, Trevor
Grafton

[dale]

I 've had decks built for me and have always asked for flashing on top of the joists. You can use either aluminium, or the plastic dampcourse used in brick work.