In north or south carolina over the weekend, the deck, at a rental
vacation house, I think, collapsed with 24 people on it, falling 10
feet. 4 still in the hospital, 2 of them in critical condition, as of a
day or two ago.
The news says "rusty nails".
Wouldn't staiinless steel screws been the right thing to use on an
ocean-front property? Or galvanized screws if there are such
Do people properly use nails for decks? If they had used galvanized
nails,how long before the salt air rusts them? Or does rusty imply
that they were not galvaniized?
And finally, what does salt air mean? The sodium and the chlorine
are both floating in the air? Seems hard to believe, but when I had a
salt-water aquarium, salt would pile up outside the glass, all the way
from the top to the bottom of the 10 gallon aquarium iirc. The water
never splashed or overflowed so how did the salt get outside the
A friend took me sailing, and I woudn't take my new, good camera out of
its bag while on the sea because I didnt want the salt air to damage it,
but I know other people use their cameras on salt-water boats. Don't
they risk damage? He was annoyed at me, because he wanted me taking
pictures of him in his captatin's cap etc.
Salt water laughs at galvanized nails. Even the heavily coated "hot
dipped" nails will not last very long (in the building sense).
I suspect there was also a design flaw. Nails should never be load
bearing. You should have wood sitting on top of wood with the nails
only providing lateral support.
Deck boards sit on joists that sit on beams that sit on footings.
Generally on the sea shore, salt air refers to the mist from the surf
that gets on everything. I do think some salt may be carried in water
vapor but I am not sure exactly how. I do know my house is 3-4 miles
from the gulf on a brackish river (ranges from 3 to 28 PPT) and things
rust a lot faster than they would if I was completely away from the
I keep my camera in a zip bag unless I am actually taking pictures and
I put it right back. It is also not that expensive a camera.
If I understood previous discussions correctly, nails are as strong or stronger than screws. Screws are always preferred if something will need to be removed and replaced, otherwise nails (if the right type) are preferred.
On Tuesday, July 7, 2015 at 4:42:07 PM UTC-4, TimR wrote:
only non magnetic screws or nails should be used with newer treated wood, or in salt environments.
perhaps building codes need to be changed to prohibit wood decks.
moving to concrete type decks which cost more but last far longer
| If I understood previous discussions correctly, nails are as strong or
stronger than screws. Screws are always preferred if something will need to
be removed and replaced, otherwise nails (if the right type) are preferred.
Nails generally have much better shear strength
because they're softer and thicker. Screws are good
for holding down deck boards, but not for structural
I rebuilt railings on a rotted deck awhile back that
had been constructed with several types of square
drive screws. That made me wonder about the building
code for them. I'd much rather trust a raining toenailed
to the post with nails than with screws.
It depends on the screws. Simpson sells some very capable ones for
their connectors that duplicate or exceed the performance of 10d
You should never have any of these is shear anyway. When building a
deck the load should be wood on wood (deck on joists that sit on beams
that sit on posts or footings
The joist hangers mentioned previously are not really that good with
CAC or ACQ wood anyway unless they are stainless and certainly not out
in the weather.
| You should never have any of these is shear anyway. When building a
| deck the load should be wood on wood (deck on joists that sit on beams
| that sit on posts or footings
| The joist hangers mentioned previously are not really that good with
| CAC or ACQ wood anyway unless they are stainless and certainly not out
| in the weather.
What about when one side of the deck is
attached to the house? And what about
railings? Or cases where a beam is either
unnecessary or impractical? I don't see
many decks that are entirely resting on beams.
What about steps attached to the deck side?
There could also be weakness where joists
attach to beams. (Ideally those areas should
be reinforced with hurricane ties, but that doesn't
always happen. Even then, if hurricane ties
are attached with screws it's possible they could
be sheared with movement over time.)
I don't know who was talking about joist
hangers, but personally I don't see any problem
with them. I've never seen rusted out joist hangers.
Personally I think the fad around high-tech and
stainless steel fasteners is just that. Sometimes
it's marketing to sell very expensive replacements
for perfectly adequate products. Other times it's
a case of reinventing the wheel. That's become
almost epidemic -- constantly changing technology
that doesn't even have time to really be tested
before it's replaced with something else.
If the deck is "above ground" enough to require a railing, it SHOULD
Hurricaine ties are not the answer for a load bearing structure.
Building it to BEAR the weight is. That means wood bearing on wood,
not supported by friction and fasteners in shear.
A rim joins set INTO a 6X6 post and connected to the post with
carriage bolts qualifies as "wood bearing on wood" and the bolt is not
loaded in shear. That's what I do for "ground level" decks. For high
decks I bolt 2X8 or whatever to the post on both sides, with the bolt
going through both planks and the post, and if the post is 6X or
larger, I set the joints into notches in the post half the depth of
the plank thickness when posts need to continue up for railings or to
support a canopy.
I've seen plenty of them - some in just plain damp locations - some in
farm buildings, and quite a few with the new PT lumber.
The new PT REQUIRES ceramic coated, stainless steel, or (in some cases
you can get away with) hot galvanized fasteners.
Standard bright plated or oxide coated steel fasteners can almost
totally disintegrate within less than 2 years when used externally
with the new PT wood.
| If the deck is "above ground" enough to require a railing, it SHOULD
| have beams.
It depends on the deck and the size. A stair
landing 4x4' is a deck, but it would typically
be attached to the house on one side and
supported by corner posts on the other. The
same is true of attached decks in general.
Where I live anything over 30" requires a railing.
Are you saying that you'd build a 4x4 stair landing
with 4 posts and 2 beams? I hope not. Maybe
you didn't understand what I was saying.
| Hurricaine ties are not the answer for a
| load bearing structure.
Hurricane ties are designed to keep the joists
from lifting off the beams in strong winds. I
was talking about the risk of movement and
therefore instability where joists sit on beams.
Around here that is a stairway landing or a "porch"
I would LIKELY use 4 posts even for a second story stair landing -
built to be self supporting and free standing, but also fastened to
the house structure.
For a lower structure definitely a free standing structure. Both my
front veranda (about 6X22 feet and a foot off the ground) and my rear
deck (12x12 - about the same hight) are built free standing - on
pilings for the porch, and on 4x4 posts in concrete for the deck. The
front porth has 1 4x4 post at the one corner that supports the corner
of the overhanging roof which is the only real attachment of the
"deck" portion to the house.
I built a second story 12X20 deck for a friend years ago that was a
good 12 feet above ground - all free standing on 6 6x6 posts and
attached to where the original (3X6 foot) "balcony" was bolted to the
wall at the door. It was all cross-braced so that it was rigid in all
directions without bolting to the structure of the house - bolting it
was just "belt and suspenders" That was 18 or 20 years ago, and it was
still standing last year - I think it has had deck boards replaced
(all 2X6 PT SYP decking originally) All beams bolted to posts, joists
on top of the beams, and decking screwed ontop of the joists.
Cross bracing bolted to the posts.
| When you have a ledger fastened to the wall, it should be with lag
| bolts and the joists should be on top of the ledger, not nailed to it
You've got only 1 1/2" for the joists to sit on, and
that's assuming you run them up to the house sheathing.
(Which is then protected by what? Flashing?) Then
how do you attach to the house? By nailing the
joists through the sheathing? All that just to avoid
using hangers? If you're so convinced that hangers
are no good then why not use some kind of cleat
board under the joists?
I don't think I've ever heard this opinion about
hangers before, and I don't think I've ever seen
a deck built in the way you're describing. All I can
picture is 2 vertical feet of siding removed, with a
2x12 attached along the bottom foot; aluminum
flashing going up under the siding at top and down
over the 2x12; then your deck perched on that
2x12. That's how you do it?
I have never actually built a deck on a ledger board for all the
reasons you describe. They have been free standing and only attached
to the house for lateral support.
As for joist hangers, they may be fine outside for inland, northern
use. In sub tropical or seashore locations not so much.
When you are building, you should be looking for 40-50 year life spans
at the minimum. Maybe that is just an old fashioned idea though in
this "fix it and flip it" mindset those TV people sell us.
24 people with an average weight if 200lbs is 4800 lbs, or about 2.5
tons. Remember that most young people are overweight today, so 200lbs is
a fair guess. They were probably dancing around too, and that motion
adds to the problem. Now add all furniture, grills, coolers, speakers,
etc, and we have 3 tons, (not including the weight of the deck itself).
Too many people on ANY deck......
A 10 ft drop is significant, but not all that far down. Its hard to
believe some are in critical condition, for only 10 feet, but that
depends on what was on the deck to fall on them.
Modern treated wood is mostly treated with copper. Nails/Screws should
be MADE FOR IT. Stainless steel is one of them that work. There should
have been metal truss joiners too. I bet there was none!
I dont know anything about salt effect (in the air). I dont live in such
a place. But I'll bet they did not use enough nails in the first place.
Never get cheap with fastners.....
The deck was probalby never made for that many people. Maybe the condo
building rules will now require a stated ammount of people allowed on the
decks. Seems that not too many years ago some big hotel had some stairs or
something like that fall when it had too many people on it during a big
Each kind of treated wood needs the correct kind of nails or screws made for
it. Use the wrong kind of nails and the treated wood will 'rust' them out
in short order.
Many people are killed by falls from under 10 feet. They fall and just hit
their head wrong. Last year my wife tripped over something in the bedroom
and fell on a floor with carpet. She broke her wrist just by landing on it
wrong. A few years back a friends daughter was on a horse near a road and a
car went by and the horse bucked her off. She hit her head and was in bad
shape for a couple of weeks. If she had not gotten treatment very quickly
after the horse bucked her off she would have died. The doctors haad to
put her in a drug coma for about a week, cut a hole in her skull and put a
plastic plate in her head. She seems fine now thanks to the doctors.
On Wed, 08 Jul 2015 00:47:50 -0500, firstname.lastname@example.org wrote:
A properly constructed deck can hold 3 tons, no problem - but not a
bouncing 3 tons. We don't know how it was supported - on posts or
cntelevered, or posts and a plate fastened to the house - and if a
sill, how it was fastened. If on posts, how well was it cross-braced.
What wood? Cedar, old style classic PT lumber, or the new PT lumber.
What kind of nails were used, and was everything gone with nails or
were there bolts used to connect the main structural members? Then
what kind of nails.
Building a deck on 2 posts and a sill nailed to the structure (rim
joist) of the house with plain nails and no crossbracing on the posts
would be approaching criminal negligence, regardless what lumber was
A free standing deck supported with 4 or 6 or more posts, properly
anchored and crossbraced, or with the plate bolted to the structure of
the house would be MUCH better.
The posts and beams of the deck structure should be bolted together
with hot galvanized or stainless steel carriage bolts, and the floor
joists should rest on the beams. Fastening the joists to the beams
with joist hangars may be OK for a ground level deck made of cedar or
classic PT, but the new PT rots the straight galvanized joist hangars
very qwickly, and the straight (not spiral or "ardox") roofing nails
most guys use to fasten them are definitely not up to the task.
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