Decking Collapses.

[ringtail]

Ok, The Ascot deck collapse. Picture a grand Qlder about 2.5 - 3 mt off the ground. The front deck had solid balustrade ( weatherboards) as some did at the time. Below the weatherboard was a bearer that ran across the width of the deck. The deck joists were housed into this bearer ( a common practice in the day) about 25 mm. Imagine joist hangers but without the joist hangers, just the end of the joist sitting in a checkout in the inside face of the perimeter bearer. The joists were fixed with a skew nail either side into the bearer. At the house end of deck was a pole plate or ledger beam bolted to the house. The joists sat on top of the ledger and were secured with skew nails.

Heres what happened. Over time, with deck movement, vibration, deflection and no cross bracing under the joists, the front perimeter bearer deflected outwards ( away from the house). Over time this deflection grew more and more until...... the first joist fell out of its checkout. This joist then wedged the bearer out further until the second joist fell out. Each joist fell out in turn and with the load ( people) on top the entire joist and decking combo came crashing down - 3mt. Some of the joists were still connected to the ledger at the house.

How did the coroner work it out ?

Easy. The underside of the deck had been recently painted. The ends of the joists that were housed into the bearer were unpainted or of a different colour to the fresh paint. Upon investigation it was seen that some of the joists ( and more importantly, the first few) were sitting in the bearer check out by 2 mm maximum. The nails were badly corroded ( brights) and in some cases had corroded right through. It was found that if the deck had cross bracing to the underside of the joists and onto the bottom of the bearer it probably wouldnt have happened. It was also noted that fixing through the outside face of the bearer into the end grain of the joists or skew fixing from the outside should have been done. It was also recommended that a ledger should have been placed under the joists to give a better margin for deflection. It was also a big wake up call for inspecting the deck on a yearly basis.

[ringtail]

The other one at Morayfield happened as a result of bad building practice. A external corner of the high set house house had 3 studs making up the corner. Just normal clear pine. the builder projected the deck bearer through the cladding and sat it on / in these 3 studs. In addition a post was projected up off the top of these studs and the bearer. Sheet flooring was put down as the deck floor and was cut around the post. Insufficient flashing and sealing around the post penetration let water run down the post, past the floor and onto the clear pine studs that were holding the whole corner of the deck. The pine rotted and gave way and the rest is history.

[ringtail]

Ask and ye shall receive :D

[tissue]

Ok, The Ascot deck collapse. Picture a grand Qlder about 2.5 - 3 mt off the ground. The front deck had solid balustrade ( weatherboards) as some did at the time. Below the weatherboard was a bearer that ran across the width of the deck. The deck joists were housed into this bearer ( a common practice in the day) about 25 mm. Imagine joist hangers but without the joist hangers, just the end of the joist sitting in a checkout in the inside face of the perimeter bearer. The joists were fixed with a skew nail either side into the bearer. At the house end of deck was a pole plate or ledger beam bolted to the house. The joists sat on top of the ledger and were secured with skew nails.


I think its a good idea to have this thread up, so people understand these houses. Im in a property thats similar to the Ascot one, which has the exact same arrangement as above for the front and rear verandas. It must have been one of the first things that we fixed when moving in, as you could really feel the movement in the verandas when walking on them.

I cant imagine how many more properties around Queensland would be in a similar situation. Scary stuff. Recent inventions that increase loading (spa baths, marble tables) dont really help with the situation either, as was evidenced in Ascot unfortunately.

[Bloss]

ringtail said "a common practice in the day' and maybe it was (insert cheap shot - 'in Qld' :wink:) , but it was never good practice.

In any case this points to the need for good information - especially to new house owners especially if the residence is more than 8-10 years old. In the ACT a building inspection report is mandatory to be supplied by the vendor to all prospective buyers (or auction bidders). We can have a discussion of how good these are (and like all such things as good as the person is that does them!), but I have seen hundreds and the poor state of external structures is often highlighted. Then comes the problem - once the mind is made up these sorts of issues are brushed aside (yeah, we'll fix that later) and then never thought of again - until it becomes too visible to ignore. Usually that's not dangerous or an actual failure, but sometime is (or could have been - I know of one low deck collapse at the housewarming. That had some bruised and scratched guests and embarrassed host, but when I checked the front deck >3m high, same poor construction. So it was just luck that there were not deaths or serious injury.)

Amazes me that the biggest investment made by most Australians and they do next to nothing on critical maintenance. Spending thousands on a garden or a spa or a BBQ or a 'roof restoration' which is cosmetic only, but do not bother with the fundamentals (even termite inspections - which generally happen after termites have been found and then the annual cost is seen as an expense not insurance).

Of course as was found in the ACT after the 2003 fires around 30% of the damaged or destroyed houses were not insured - even more had no contents insurance. Sure those people lost their homes and that is sad, but so did those insured and the whole lot of us pay for the freeloading.

Bit off-topic . . . but draw it back - if you do not maintain your house and there is a catastrophe then a battle with your insurer is possible, maybe even likely and even if the blame is shared (for eg. back to a builder in the past) it will cost time money and anguish.

[strangerep]

[...] We can have a discussion of how good [building reports] are (and like all such things as good as the person is that does them!), but I have seen hundreds and the poor state of external structures is often highlighted. Then comes the problem - once the mind is made up these sorts of issues are brushed aside (yeah, we'll fix that later) and then never thought of again - until it becomes too visible to ignore.

Totally agree. That happened to me. The building report didn't sound "too bad", and even though he told me verbally that "the woodwork is in very bad shape", I didn't understand clearly what he meant. I thought it just needed painting. (I know a LOT more now, of course.)

I don't see any real solution rather than implementing a much more rigorous building inspection system that summarizes what repairs are needed immediately, what repairs are likely to be needed within 3 years, likely costs, etc. And if any repairs are needed "immediately" then the property should be forcibly taken off the market until they're done. And you'd have to lodge a copy of the report with some government agency, or whatever, so that it can be proven whether you knew about the problems if inattention to repairs causes serious harm. And such reports should be repeated for all properties every 10 yrs or so, possibly depending on the type of construction. But imagine the cost and the uproar at such a proposition.


Amazes me that the biggest investment made by most Australians and they do next to nothing on critical maintenance.
Most don't understand the need. There's also the human psychology thing whereby we tend to think (subconsciously) that (in the absence of experience) things will continue as they have in the past. This is quite hard to break.

IMHO, much more draconian durability regulations should be enforced for exterior timber structures. A layman rarely comprehends the realities...

[ringtail]

Absolutely disagree with the building inspections. Its totally at the discretion of the inspector. Some are anal, some are not, some have no idea. To have a house removed from the listings because it may be potentially dangerous is ridiculous. What if the vendor simply cant afford to make the repairs, will the house stay off the market forever ? The purchaser knows what they are buying and can always negotiate a lower price. The vendor, of course, has every right to refuse. If you want the location then this is my price. A homeowner has no obligation to perform any maintenace at all. None. Sure if a fatality or injury occurs their public liability insurance may not come through due to their negligence but thats on their own head. Normal wear and tear and ageing are just that. A purchaser must understand that a 15 year old deck on a house is not new and may only have 2, 5 or 10 years of servicable life left. The plumbing could be totally shot, the electrics too. The old stick built roof has no tie down at all and the inspector says its dangerous, yet its been there for 70 years. Builders warranty is only 7 years on new structural work, same with owner builders - after that is a grey area. Of course non approved structural alterations are a different story in the event of a failure. Most if not all building inspections have more get out clauses than actual inspection content and clearly state that they are based on visual inspections only and my guess is they would hold very little weight in court. Passing the buck with red tape and bureaucracy is not the answer. Purchasers need to accept what they have bought and have the budget to fix what requires fixing and accept responsibility for their own actions.

[barney118]

I agree with ringtail. I like the comment houses built 70 yrs ago that defy current building standards says we are skimping out on new structures. No engineering needed back then....

[Bloss]

As it happens I agree with ringtail & barney118 - more draconion rules and inspections are not the answer. Like most rules that society creates there are only ever few who break them - we need to focus on those individuals who do and not penalise the rest who comply. But that does not mean there aren't ways of ensuring buyers are fully informed - and that's where there can be assistance. It works well in the ACT - my comment was about those few assessors/ certifiers who do not comply to the rules they are supposed to (as per my second sentence!).

[ringtail]

Was there any ever doubt that we would agree :D:D:D:p

[Bloss]

:2tsup: probably not . . . but I can be a contrary sob sometimes . . . :-

[ringtail]

:2tsup: probably not . . . but I can be a contrary sob sometimes . . . :-

Me to. No I'm not, yes I am, no I'm not :D

[SilentButDeadly]

Sadly, rules in this case are often thought to be required by those processing the forms to protect those who are processing the forms - that's why they get made.

I'm with you guys but I also understand the mindset behind having the rules as well. Even if it seems mad...