California Still Figuring Out Construction Flashing

They need more laws and more taxes.

Well, there were 13 drunken, rowdy kids jammed onto a 32 square foot balcony. It was probably loaded right about at the code limit. At that sort of density, there was a significant danger of people getting pushed over the railing, even if the deck hadn't broken; I've seen that happen.

We had that nasty deck collapse in SF in 1996, again a deck over-packed with party types.

One deck on our house is cantelevered like that one, and had some notching of the joists from water dripping off the side of the house. We caught that before it was too serious. But we also have uprights from the ground into the corners, which the one in Berkeley didn't.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

And none of Arizona's water >:-} ...Jim Thompson

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Den fredag den 19. juni 2015 kl. 01.22.02 UTC+2 skrev John Larkin:

news here was that the code limit was ~600kg even with a safety factor of 1.5 not much for 13 people, especially not if they were moving around

-Lasse

unskilled labor:

150617-story.html

More info:

You can see from the photo the support beams were completely rotted. A lot of finger pointing here but the city approved the plans, the city should ha ve been sending inspectors around during intermediate phases of the constru ction to verify it was being built to plan. The building owner should be of f the hook under the hidden defect doctrine.

Well, let's see if the numbers work. I had a hell of time trying measure the size of the balcony. As usual, the new editors were very careful to remove all numbers lest it tax the brain power of the readership. My best guess is 3 x 7 ft based mostly on the height of the French doors.

Googling for live load construction tables, I find: which suggests a maximum of:

lbs/ft^2 (kN/m^2) Balconies (exterior) 100 (4.79) On one- and two-family residences only, and not exceeding 100 ft^2 (9.3 m^2) 60 (2.87)

3 x 7 ft = 21 ft^2 21 ft^2 * 100 lbs/ft^2 = 2100 lbs max 13 students * 150 lbs each = 1950 lbs

So, in theory, the balcony should have held the load.

If you look at the photo of what's left of the balcony,

you might notice that there is quite a bit of rot along the door line and much more on the end floor joists. My guess(tm) is that this deck had standing water on it for quite some time. The increased rot on the end joists is from water going over the ends of the balcony, instead of over the middle.

When the balcony literally peeled itself off the outside wall, the lower part of the joists were in compression, while the upper parts were in tension. The result is the triangular tear pattern, with more wood remaining along the part that was in compression. If the standing water was against the wall, that's what I would expect. If it were in the middle of the balcony, the tear pattern would be either parallel to the wall, or the reverse of the photo. That eliminates the possibility of a leaky potted plant, drip watering, carpeting, or a sagging balcony floor center with standing water in the middle.

For once, methinks Mr Bloggs is correct. The flashing against the wall and under the door wasn't done correctly. Looking at the photos, I don't see any evidence of wall flashing, ledger board, ledger cap flashing, or metal joist hangers. The balcony seems to have been attached directly to the building wall and was either very badly designed, badly built, not to code, or some combination of these. Unlike decks, balconies do not have a drainage gap between the wall and the start of the balcony floor. That is to prevent raining on the balcony below. Therefore, a drainage channel to the sides of the deck, or very good flashing and caulking is required. I don't see either.

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Jeff Liebermann     jeffl@cruzio.com 
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On Thu, 18 Jun 2015 15:25:46 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:

I for one cannot believe the stupid bastards are trying to blame the "rotted wood" for an "accident" which was clearly the result of utter stupidity on the part of the "modern university student" folk..

Out having a cigarette or a "funny cigarette" or an "in vogue" "e-cigarette" on a balcony built to hold about five adults. And these were Berkeley's students. Not very bright at all, in my book.

The culprit? The idiots packed 13 of themselves onto that *tiny* "balcony".

I feel sad that the tragedy occurred, however, it was NOT the "fault" of the "rotted wood". There were clearly enough joists, even rotted, to hold the number of adults it was designed for, which was no more than 5 and certainly NOT 13.

On Thu, 18 Jun 2015 16:21:56 -0700, John Larkin Gave us:

You are retarded. Those balconies were designed for about 5 adults, max.

On Thu, 18 Jun 2015 16:21:56 -0700, John Larkin Gave us:

It was 5 stories up, idiot.

On Thu, 18 Jun 2015 16:30:37 -0700, Jim Thompson Gave us:

Especially not the alfalfa farmers (who export most of it), where they overwater at about a ten X rate. Far worse than the Almond growers do.

Most Californians are idiots about water usage too (read among other things).

On Thu, 18 Jun 2015 16:40:35 -0700 (PDT), Lasse Langwadt Christensen Gave us:

Motion had nothing to do with their brain dysfunction. They could have been frozen solid and placed there one at a time by a skyhook. It was still too goddamned many.

All for a cigarette most likely too. They are certainly (obviously) too stupid to have been out looking at the stars or planets.

Pressure-treated beams, or steel, should be mandatory for things like that.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

And you are Always Wrong. The area was about 38 square feet. Code requires it to be designed for 60 psf, and it was actually designed to bear 100 psf. 100 psf computes to 3800 pounds, 292 pounds for each of the 13 people. So by design it should bear all the people that could pack onto it. What went wrong was not properly waterproofing, and inspecting, rottable wood.

In Truckee, the requirement is 400 psf, from snow loading. Lots of decks failed up there in early 2011, from the huge snowfall and latent dry rot.

All such structures should be built from rot-resistant stuff. It's astonishing that most aren't. In another ten years, those decks in Berkeley would have fallen of their own weight. All those Irish kids were the test case.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

There is no sign that the balcony railing pulled out of the wall. It was probably not attached. I'm surprised they build these things 100% dependent on the cantilever. It would be trivially easy to hide a structural diagonal brace in the railing that was lagged into the wall and held the far end of the balcony up.

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Paul Hovnanian     mailto:Paul@Hovnanian.com 
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Answer: Eight. Twelve if the light bulb is cross-threaded.

Our third deck (this being California, we have four!) has the same problem. Rain, or more often fog condensation, drips along the side of the house, hits the proper flashing, and wets the tops of the beams a couple of inches from the house. The crap wood rots and fungi eat v-notches in the tops of the beams. I could post pics.

Ours aren't close to failing yet, so I need to come up with a fix to stop the rot. Deflect the water around the beams but still allow them to dry. I'm an *electrical* engineer.

The two upright 4x4s, from the ground up to the corners of the deck, were mostly rotted through, too. We just replaced them with pressure-treated.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

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Not really..that "brace" would tie into either a jack or king stud, and stu ds are not designed to resist horizontal pull, they are designed to resist vertical compression only, you go pulling horizontally, especially around m id-length, and that piece comes right out.

On Fri, 19 Jun 2015 10:35:01 -0700, John Larkin Gave us:

Must be what caused your brain to fail too.

Normal pressure treating doesn't keep lumber from being damaged by water at all.

yeah, it would take some effort to exceed that.

no hangers or ledger because the balcony was on the floor joists of the room behind it which extnd over, and are supported by, the wall and lintel below them.

could be damp in the walls, which appear to be wooden with render finish, a combination that often doen't work well anywhere that has regular rain,

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umop apisdn