Thread: Spotted Gum or Kwila

Kwila will bleed when it gets wet so if you use it, any thing under it will gets browns stains on it.

G'day.
I hope you like walking on corragated Iron roofing, cause that is what will happen to decking 140mm wide.

Most decking is only 65 or 85mm wide.

Good luck.

140mm decking is quite common down where I live. My neighbour has a spotted gum deck in boards that wide. It's about 25-30mm thick though. It's been down for 2 years and no corrugations yet. I don't expect any.

My merbau deck is 90mm.

I prefer the darker colour, so would go with the Kwila if it was me.

The spotted gum decking is Supa deck 32mm thick. Was advised to put joists in at 600, even tho I'm sure he said it could be larger distances apart.

Regardless, I'm using 450 ctrs. Two fixings in each.
Would that help with cupping?

Shrinkage is expected to be about 5-8mm gap after laying them hard together.

kwila only because it is KD other wise spotty would be my choice would not us unseasoned dressed timber . as long as it what they call a super deck extra thick should be fine . i have used 130x19 before by a pool only had to replace two boards for cupping

Beware of the Kwila bleeding when wet. Pool splash would be a minor concern, but beware of stormwater runnoff getting to the pool or other surrounds.

Originally Posted by Fatwood

The spotted gum decking is Supa deck 32mm thick. Was advised to put joists in at 600, even tho I'm sure he said it could be larger distances apart.

Regardless, I'm using 450 ctrs. Two fixings in each.
Would that help with cupping?

It would be mandatory. What sort of fixings are you using?

Shrinkage is expected to be about 5-8mm gap after laying them hard together.

So the spotty is damned near green. What are you being quoted?

How do you feel about ironbark?

Thanks everyone.

Exador to answer your questions:

- fixings = I was going to use batten screws. ?

- How do I feel about ironbark? I dont know, I only made the decision as the two larger timber suppliers where I live (Sunshine Coast) quoted me either spotted gum or kwila.



So I assume the 32mm thickness of the "supadek" will help reduce cupping to some degree ?

Originally Posted by Fatwood

Thanks everyone.

Exador to answer your questions:

- fixings = I was going to use batten screws. ?

- How do I feel about ironbark? I dont know, I only made the decision as the two larger timber suppliers where I live (Sunshine Coast) quoted me either spotted gum or kwila.



So I assume the 32mm thickness of the "supadek" will help reduce cupping to some degree ?

Yes, it will help, but you'll likely get splitting, especially if the spotty is so green as to shrink 3-5%. You'll also be well-advised to pre-drill your boards, as both of those species will split if you try to directly screw them though. It also wouldn't hurt to countersink and to seal the holes with some of your deck seal before inserting the screws. Batten screws tear out the top of the holes and can allow water in, especially when they're vertical, as in a deck. Water is what will bugger the thing.

The reason for the question about ironbark is that it is very stable, class 1 durability and would be the perfect timber for the deck if you like the red-brown colour. Out of interest, what price were you quoted for the others?

Spotted Gum 140 x 32 is $8.95 Lin/m
ST & B Spotted Gum 140 x 25 $8.91 Lin/m (would love to know what ST & B means)

"Mixed hardwood Supadeck" 136 x 32 $12.22 Lin/m

Kwila 140 x 25 $8.15 Lin/m


I know the top one is not kiln dried. I have no idea about the others.

G'day.
ST & B means Standard Grade & Better. It is a mix of Standard grade and select grade. Spotted Gum is ussualy 60% Select and 40% Standard.

ANother way of writing Standard and Better is S&B. This is what we use.

Originally Posted by Fatwood

Spotted Gum 140 x 32 is $8.95 Lin/m
ST & B Spotted Gum 140 x 25 $8.91 Lin/m (would love to know what ST & B means)

"Mixed hardwood Supadeck" 136 x 32 $12.22 Lin/m

Kwila 140 x 25 $8.15 Lin/m


I know the top one is not kiln dried. I have no idea about the others.

Price is about $1500/cube for the green 140x32 and about $2000/cube for the S&B. If you're interested, I can supply any number of Aus hardwoods in those sorts of dimensions for $1100/c.m (inc GST) air dried and dressed, or if you don't mind stacking,drying and dressing it yourself, $800 green off the saw. I mentioned ironbark because I have a stack of 25mm x 150mm ironbark, which would be perfect for your needs. I actually cut it for use in a fence at our current premises, but we're moving, so it's now surplus.

Give me a pm if you're interested.

ok so bear with me here, how much is that per m ?

Do you have a link to an image so i can see what ironbark looks like (i'm also searching for one myself).

Is it in random lengths ?

If I used it could I just use it as soon as I got it I wouldnt be that keen on dressing it and drying it myself.

Originally Posted by Fatwood

ok so bear with me here, how much is that per m ?

Do you have a link to an image so i can see what ironbark looks like (i'm also searching for one myself).

Is it in random lengths ?

If I used it could I just use it as soon as I got it I wouldnt be that keen on dressing it and drying it myself.

Price would be $4.13/lm inc gst for 150x25, which would be dressed out at around 140x20 (or 130 x 20 if you prefer). We can also supply you with ironbark bearers and joists if you like. Length would be minimum 3m.

I'll take some photos when I get a chance.