# Forum Home Renovation Decking  Replacing hardwood deck joists with treated pine?

## woodmark

I'm replacing some rotting hardwood joists in my deck, and I was wondering if treated pine might be a better replacement timber? These joists get rained on, and that is why the hardwood ones rotted in the first place, as far as I can tell. Would treated pine actually last longer? (I saw one post saying that you can get treated pine guaranteed for 40 years these days!)  
These timbers won't be in direct ground contact, but will be weather exposed, as I mentioned.

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## bpj1968

My current house had a 1st floor deck with hardwood joists, built late 80's.  15 years later these were rotten on top and the decking boards barley stayed on.  Combined with the Oregon used for the railing it was a death trap.  Demolition was just a matter of pushing it off the steel beams.  I have since rebuilt and expanded using treated pine. 
Treated pine is good for at least 40 years, by which time you would probably be looking at doing something different anyway.  The only issue is that treated pine has a lower F rating and needs bigger sizes, so bear this in mind if you are only replacing a few joists.  You can also get various rolls of plastic designed to sit on top of joists to help stop water damage.  I think one is called Protect-a-deck and available at Bunnings etc.

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## ringtail

If you prime and paint the hardwood first, as you should if it is exposed to the weather, it will last for awful lot longer than pine.

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## Bloss

> If you prime and paint the hardwood first, as you should if it is exposed to the weather, it will last for awful lot longer than pine.

  Nope - just ain't so - although depends on a few things too, like timber type and weather harshness & exposure, type of fixings used etc. 
Safest bet by far is to use H3 or H4 treated pine, use the joist protector strips too if in a higher rainfall area, SS fixings (or those with coatings for TP) and fluted surface face down.

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## ringtail

Arrrgghhh, another advocate of using treated pine in structural applications. House frames not included, there is no way a piece of juicy, wet, pine - regardless of treatment, will come close to out lasting a class 1 durability piece of hardwood. Any builder worth his salt in QLD wont touch pine for a deck, but maybe thats just the way we do it up here. Its ironbark or spotty gum joists, with whatever HWD decking the customer specs. In fact, at a recent QBSA seminar I attended there were quite a few chippies there who asked why pine is not banned from been used for decks. The timber advisory rep said that pine has is place and applications and is easy for the general public to use, but he agreed that nothing beats hardwood for durabiltiy and structural integrity when it comes to decks and other like situations where reliability of product is vital.

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## Bloss

This is largely a DIY site especially those seeking advice on decks so we are not talking about 'any builder worth their salt'. The posters asking questions on here are also national and international. They are not in Qld or Northern NSW with access to durability rated grade 1 HW timber and for the most part wouldn't know what to look for if they were. 
Most decks in any case have a life of under 20 years simply because of lifestyle and building owner changes and are usually dismantled before any weathering damage occurs. 
I worked with NSW north coast timbers for many years and yes they were excellent although until improved milling in the 80s & 90s quality was patchy - my Dah & I selected from a couple of trusted local mills to get the quality we demanded. 
So you can be a HW snob if you like and I probably would too if I had access to good HW, but in the world outside the independent republic of Qld (and Tassie too) the HW quality is patchy at best whereas treated pine is milled and processed to pretty high standard and quality around the country - and the longevity used as per specs is proved. 
Probably worthwhile spending a bit more time on this site before you use ad hominem attacks on other members (sorry, forgot you are from Qld - that's 'before you play the man not the ball') . . .  :Cool:

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## ringtail

Dear Bloss, firstly, I should have put LOL or a smiley face after my " attack "on you, so sorry bout that. Secondly, yes I am a hardwood snob, and yes it is because of the availability of it up here. Thirdly, I agree with you about the dubious quality of hardwoods, but it is a reversal up here. Todays hardwood is bollocks compared to what was getting around ten years ago, its still good though if get picky and dont accept junk from the mill. I also agree that as treated pine is the norm down south, it would probably be easier all round if the OP went this way. 
Now, for your info, I was born in Canberra and moved to QLD in 1980 when I was ten, so there.
And, how can the longevity of a product be proved if the product itself has not even existed for 40 years, let alone been tested for 40 years. Pure speculation. And yes, this is a DIY site, but none the less, the DIY 'er should be aiming for professional results,especially with decks. If they dont want to do it properly they should stick to their day job.I dont think anyone would disagree with me on this ? 
But, I'm so not going to argue with Bloss. I respect a man who sticks to his beliefs, so lets just agree to disagree eh ?

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## watson

:Kiss:

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## Bloss

watson - too subtle for me . . .  :Wink:  
Treated pine has been around for more than 60 years so there is plenty evidence of its long use (albeit the treatment types have varied). In any case there are plenty of accurate and reliable ways to test longevity without simply waiting for the effluxion of time! I am not a great advocate of TP so much as for the practicality of it for most users. 
Professional results for deck will have little to do with the sub structure type and much to do with care taken, ability and following good advice and guidance. Taking sides on what type of substructure is pretty pointless and a false choice - what matters is what suits the end-user and they can choose well or badly in any material and can build well or badly (or just OK) likewise. And those choices of material are highly dependent on location and what's available and what the user feels comfortable with rather than any leaning towards a particular preference. 
Your post came on a little strong IMO so I pushed back a little - I suggest we are in furious agreement - both wanting to get members here to achieve a good result.  :2thumbsup:  
And it seemed to wake watson from his slumber for a minute or two .  .  .   :Biggrin:

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## ringtail

Thats the name of the game, good results. There are some truly talented DIY'ers out there who easily put many tradies to shame. I'm sure you have seen more than enough tradie horror, along with some stunning DIY work. Some people have missed their calling I reckon. 
Good to keep the powers that be awake. How boring would life be if everyone agreed about everything. 
Nice and chilly down there ? I miss the cold....NOT.

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## Gonzo

So, what about galvanised steel?  Or, shouldnt I ask.  Cheers.

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## Bloss

> So, what about galvanised steel?  Or, shouldnt I ask.  Cheers.

  It's a fine option so long as the DIYer is comfortable working with steel - many aren't. No purists here - just pragmatists!  :Cool:

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## Halfie

Before building my decks at home (Brisbane) I asked the chippies at work what their preference was regarding TP vs hardwood, all of them said hardwood would outlast TP by a long shot, when I asked them what type of hardwood they were referring to most just looked at me blankly or said F14 GOS which isn't much of an answer IMO.  
I reckon you gotta compare specific species to treated pine to make it a fair debate or the whole conversation is pretty pointless!

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## Bloss

The quality of build and maintenance has more to do with longevity of the structure than the timber IMO (given the timber used is at minimum suitable for outdoor exposed use!). For example oregon (douglas fir)  is no longer approved for external work but I know of many structures that stood safely and strongly for more than 90 years and lots for 40 years and more. I've seen unseen untreated (but painted) radiata structures last 15 years and more. But - properly built and then well maintained. 
Simple ideas and technologies have improved things too of course such as joist protector strips, coatings for TP timber fixings and cheaper SS fixings, better paints etc. 
But - take the cheapest quote and/or build with the cheapest product or encourage your tradie to do so by not understanding the difference between cost and value and you'll generally get what you pay for - often less, rarely more.

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