Deck timber

don1751, Jan 23, 12:51am
Am building a deck and are unsure whether to use 25m or 40m decking. Quite a difference in price but I don't want to ruin the job for a few dollars. Joists are 450m spacing.
survivalkiwi, Jan 23, 12:59am
Use 40 for pine. A 25mm pine deck will feel cheap and nasty and will twist and bend beyond belief. As a builder I prefer kwila but it is a lot more expensive. All joist should be at 400 centers but with 40mm pine 450 will be ok.
tintop, Jan 23, 1:24am
Deck here is ex 25mm pine over joists at 450 centres. Absolutely no warping twisting or looseness after 10 years on north side of the house exposed to all weathers

However it is top grade timber, all clears - no knots and straight grained.

Drilled and screwed at butt joints.
newtec1, Jan 23, 1:28am
Yep go for ex 40mm .Don't be fooled into buying merch grade or seconds,get premium and it will look $1mil dollars. As kiwi said 25m will look cheap. Keep the gap to a minimum, a 60mm nail is plenty of gap because pine will shrink to make the gap look bigger. If you want to add a feature look to the deck and you buy a good run of boards, try 1 grip tread up and the next smooth, no one else does it but i can assure you it looks great,especially with Kwila. That's my trade secret for the week.
newtec1, Jan 23, 1:30am
Yes clears make all the difference to a good look.
kellrae, Jan 23, 2:12am
Just having a deck built using 140 w 40 thick vitex. It looks fab when oiled with CD50 (special type for vitex). Worth every penny
nzmax, Jan 23, 2:22am
I totally agree with the look of clears/premium grade decking, though having worked in a timber yard a number of years ago, most people want the look of clears, but only want to pay the price of merch grade. We had people expect us to pull apart every pack of merch grade decking so they could pick out the best ones. Bear in mind, that there might be only 7 or 8 sticks that would pass as clears in a pack of 100 sticks.
newtec1, Jan 23, 3:11am
Yes vitex is probably the best of the lot. A very nice finish,easy to work with and clear texture. A bit more expensive ,but that's what you get when you buy the best.
newtec1, Jan 23, 3:16am
That's the whole purpose of the difference in price, you pay less and take your chance of the quality. If you have to select all the clears they would be at the clear price. When we precut a frame we would use # 2 and cut out the knots to suit the lengths we needed and use the offcuts for something else.
nzmax, Jan 23, 3:34am
Im hearing you. I would refuse to open another pack of decking. If they were only prepared to pay merch price, then that's what they got.

A good suggestion to anyone doing a deck, is to check out the decking lengths available and include that in planning your deck to minimise wastage or to avoid joins if you don't want them. No point planning a deck 7.2m long and not wanting any joins when the longest length available is 6m. Ive had people get quite angry when they were picking up their decking and realise that the length they want is not available. Occasionally some longer lengths aren't available because of a shortage of suitable timber for that particular length.

Kwila decking is usually in random mixed length packs. Sometimes there are lots of long lengths and few shorter ones, sometimes the opposite. Not many realise that either, so joins are usually inevitable.
kaddiew, Jan 23, 4:11am
That's exactly what's happened to my small deck built by a builder, with 25mm pine. I didn't know there was a choice of 40mm. The deck pretty quickly started warping, twisting, shrinking, and bouncing underfoot. Very shoddy looking.
stevo2, Sep 9, 3:40pm
another builder here. if using pine,stick to 40mm. peferably clears if you can afford the extra. we mainly use kwila, purpleheart, nz redwood(50mm) or composite decking.