Another great source is
TIMBER SOLUTIONS program.
It is a bit hard to use for a novice but once you work it out it is excellent as you can make design specific span tables, instead of having to settle for preset floor load widths for bearers etc.
I posted some easy to follow (I think) instructions in this thread Great Free Software for bearer and Joist estimation
I'll amend the LIbrary tonight and insert those links. I won't download the software due to a couple of copyright problems, but I'll also include the link to yours and Deckies instructions
The attached PDF is a
simple set of span tables for decks.
I tried to make it as idiot proof as possible
I calculated these using Timber Solutions software.
I only used F5 treated pine to calculate, and the most common sizes.
The bearer table I think is the easiest to use, as you select the size joist you want, and then can match it with the bearer to work out your calculations.
NOTE although 90x90 and 140x45 bearers are listed these DO NOT appear in any span table I have been able to find.
Usual disclaimer - I tried to be as accurate as possible, but take NO responsibility
140x45mm is generally used as a joist.
Whilst many decks including ones I have built have single member bearers, the BCA requires treated pine bearers to 'doubled-up' either by nail lamination or glue lamination. Bearer span tables will always appear as 2/90x35, 2/140x35 etc.
I have many times used 190x45 single member bearers on decks spanning up to 3 metres and they are as solid as a rock. The BCA bearer requirement is a massive overkill IMO
Attachment from AS 1684.2 2010, F5 spans for N1 class wind
Like a lot of people on here I am in the process of building a deck. I have put quite a few together in the past (helping builder dad), however I have never planned one from scratch so I am struggling a bit with what to use where to make it solid yet not overkill to support a tank.
A few questions:
(1) All decks I have put together in the past are just single bearers, yet the book & AS refer to doubles. Are doubles really required?
(2) I am planning on a single 140 x 45 bearer, sitting directly in the stirrup (only got 300mm to play with), however I can't find a 45mm stirrup. Should I just cut a 45mm block to fill up the stirrup next to the bearer then bolt through the lot?
(3) Given the deck is only 300mm to the top of the boards, does this require council approval?
The decking span information is great, but what adjustments or considerations are to be made to support a spa on a deck?
These span tables are great and a must for any deck builder, however we need to remember that these tables should be treated as a minimum rather thann the "standard". Some of the specs given are known to cause problems such as deck bounce with the specified spans.
Use the tables but if budget allows, either reduce your span from the maximum allowable span, or increase your timber spec as so you allow for sufficient factor of safety.
We have far too many decks fail and i believe this to be the cause- treating the "minimum requirements" as the "standard". Quite often the extra costs incurred are minimal but the results are far better.
The only thing worse than deck bounce is catastrophic deck failure. I know for a fact that some of the spans indicated by the tables if used as a spec, WILL produce significant deck bounce. Best to up the size of the timber by 30 percent or reduce the maximum allowable span by 30 percent...
Catastrophic failures are almost always high decks (>2m) and always involve incorrect construction, (ie: NOT complying to the standard in part or full), or poor maintenance, or excessive load (often dynamic) - or some or all of those factors together. Most common if a relatively new deck is that it just been incorrectly attached (eg: simply dynabolted to a brick veneer wall) and then subjected to a dynamic heavy load - many people dancing or moving about. This ca happen once and a collapse or over a number of events that eventually leads to the collapse.
The next most common cause is due to poor maintenance (or in the case of oregon/Douglas Fir for example a material that is very unforgiving of poor maintenance) and the application of the same type of load. Fine for years & years then the 21st birthday party or 50th or a family get together increases the load, often makes it dynamic and down it comes.
That's why we have those minimum standards - but also why understanding about maintenance is important and when looking at renovating decks more than say 8-10 years old professional advice should be used on its soundness. These are general comments though - for there are higher risks in tropics and areas with higher rainfall when proper maintenance is not done. Ignorant or intentional sub-standard design &/or construction by professionals or DIYers can happen anywhere.
The standards are fine - and the way the BCA operates there are higher compliance requirements for higher structures than lower (as consequences will be bigger) which is another reason we have few failures. So build beyond the standards to get a better quality result and probably greater longevity (if looked after) - including less bounce - but don't make decisions out of fear or worry about small probability risks . . .
Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.
Which is the timber Solutions program this post refers to? The link points to timber.org web site with few different programs, but I am not sure which one is suitable for deck bearer and joist calculations.
sorry of this is the wrong way to do this, but I am about to build a deck for myself with a single 190 x45 bearer with posts at 1800mm, In your mind do you think this is okay or will it be too springy, too insufficient for strength/ span. Oh, it will cover 5.4x3m, with 2 rows of bearers.
Where can I find hardwood span tables..?
All posts listed in this thread seem to refer to pine or softwoods..?
The official Standards Australia documents specify hardwood in terms of gradings, like F17. Programs like Timber Solutions can also specify hardwood
Am i correct in thinking this Standard was updated in 2010?
I cant find a free copy the outdoor treated pine under 1 metre section.