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-   -   Using 1" thick cedar decking okay? (https://www.diybanter.com/woodworking/109887-using-1%22-thick-cedar-decking-okay.html)

Ken Moiarty June 13th 05 09:19 PM

Using 1" thick cedar decking okay?
 
I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength) as
standard patio grade cedar. My concern is not about safety per se so much
as it is about structural rigidity, solidness, etc. I don't want it to feel
like I'm 'bouncing on planks' when walking on the deck. Any suggestions,
advice, experiences? Thanks...

Ken



Chip C June 13th 05 09:40 PM



Ken Moiarty wrote:
I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength) as
standard patio grade cedar. My concern is not about safety per se so much
as it is about structural rigidity, solidness, etc. I don't want it to feel
like I'm 'bouncing on planks' when walking on the deck. Any suggestions,
advice, experiences? Thanks...

Ken


How thick exactly is this cedar, and (very importantly) what's your
joist spacing? There is stuff called 5/4 ("five-quarters") which is
very close to 1.25" thick and meant especially for decking on standard
(16"?) joist spacing. It is radius edge. If this is what you've got,
you should be fine. Nominal 1" planks will be probably 3/4 and probably
unsuitable, but I have not seem them in radius edge. I'm not sure what
you mean by "regular patio grade cedar", as the 5/4 stuff seems to be
"the" boards for decking. But it's been a while since I built a deck
and availability of lumber varies regionally.

On bouncy decks a lot of the problem is the substructure, so the
decking may be the least of your worries.

Some folks think that pressure-treated wood is death at 100 yds and
some think you can make tea with the sawdust from it. I figure that if
there's one place it's nice to avoid it it's where your kids might be
walking barefoot on it.

Chip C


SQLit June 13th 05 10:19 PM


"Ken Moiarty" wrote in message
news:v%kre.1667366$8l.1605819@pd7tw1no...
I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength)

as
standard patio grade cedar. My concern is not about safety per se so much
as it is about structural rigidity, solidness, etc. I don't want it to

feel
like I'm 'bouncing on planks' when walking on the deck. Any suggestions,
advice, experiences? Thanks...

Ken



You asked....

Cedar is a splintery wood. Try that on the SO and or small humans. I have
a friend that has to stain his redwood deck every year to keep it looking
nice. He says forget about the 4-10 year stain guarantees in Phoenix.
If I was to look into a exterior deck I would look at the reclaimed wood and
plastic lumber being sold now. Once installed you should have 10-20 years
of no maintenance. http://www.trex.com/products/whatistrex.asp?

I like not doing outside maintenance when at all possible.

I have never seen a raised deck with "1 inch" material. Since I weight more
than 250 lbs I am not into taking a step and getting that springy feeling.
I guess if you increased the stringers, ( structure below the "1 inch"
material it would be ok. Except for the yearly maintenance.

The reclaimed stuff is NOT cheaper.



jo4hn June 13th 05 11:09 PM

Ken Moiarty wrote:
I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength) as
standard patio grade cedar. My concern is not about safety per se so much
as it is about structural rigidity, solidness, etc. I don't want it to feel
like I'm 'bouncing on planks' when walking on the deck. Any suggestions,
advice, experiences? Thanks...

Ken

What is your joist spacing (16", 12")? What exactly is the thickness of
the cedar (5/4, 4/4?)? Is there a snow load? Does your roof line slope
onto the deck? For example, my deck has doug fir tubaten joists on 12"
centers with sixbasix supports holding up tubasix redwood decking. Even
though the roof slopes to the side of the deck, we had from two to six
feet of snow on it for several months this year. Until this year, I had
thought that that deck was way overdesigned. A LOT of decks in my town
ended up on the ground.
mahalo,
jo4hn

J June 13th 05 11:48 PM

"Ken Moiarty" wrote in message
news:v%kre.1667366$8l.1605819@pd7tw1no...
I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength)


Actually it has much less than half the bending strength. Resistance to
bending is proportional to the cube of the depth.
So, if the normal stuff is 1.5 inches (which is what a 2 by ... measures)
then 1 inch would be about 30% of that stiffness.
Take a few pieces in the yard and lay them out at the joist spacing you
want. Stand on them. See if you like it.
Personally I think 1" is too thin.

-j



Tony Hwang June 14th 05 12:22 AM

Ken Moiarty wrote:

I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength) as
standard patio grade cedar. My concern is not about safety per se so much
as it is about structural rigidity, solidness, etc. I don't want it to feel
like I'm 'bouncing on planks' when walking on the deck. Any suggestions,
advice, experiences? Thanks...

Ken


Hi,
My deck out at cabin has that cedar decking. Smooth round edge like
flooring material. Used deck screws for fastening. Over 5 years, yet
no problem. I think your joist strength and spacing is more important.
Tony

Fred MacMurray June 14th 05 04:45 PM

Ken Moiarty wrote:

I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength)
as
standard patio grade cedar. My concern is not about safety per se so much
as it is about structural rigidity, solidness, etc. I don't want it to
feel
like I'm 'bouncing on planks' when walking on the deck. Any suggestions,
advice, experiences? Thanks...

Ken


I finished my deck last night. :-) I built it with 5/4 radiased cedar
decking on base of pressure treated wood. The construction style is
floating dekblok with 2x8, 16" centers and I used deck screws to attach the
cedar to the frame. I'm confident for anything less than a mosh pit type
party that the structural integrity will be fine. I'm over 200lbs and the
cedar feels plenty rigid.




toller June 14th 05 05:00 PM


Actually it has much less than half the bending strength. Resistance to
bending is proportional to the cube of the depth.


Admittedly it was 30 years ago and things change, but when I took mechanical
engineering it was proportional to the square. You integrated the material
multiplied by it's distance from the center; that means squared, no?



Ken Moiarty June 14th 05 07:35 PM

Chip wrote on 13 Jun 2005 12:40:13 -0700:


CC How thick exactly is this cedar,

It's 5/4.

CC and (very importantly) what's your joist spacing?

I intend to use 12" joist spacing.


Ken



Ken Moiarty June 14th 05 07:46 PM

jo4hn wrote on Mon, 13 Jun 2005 21:09:25 GMT:

j What is your joist spacing (16", 12")? What exactly is the thickness
of
j the cedar (5/4, 4/4?)?

12" and 5/4, respectively.

j Is there a snow load?

This being Vancouver (the rain capital of so called, "Great White North"),
snow fall during the winter is usually negligible.

But as far as the kind of loads that the deck might someday need to hold, I
have visions of the deck being packed by people visiting for a family
reunion, or some such other large family event. :)

Ken



Sam Wheeler June 14th 05 08:33 PM

Done that. 1 inch cedar is solid and has no bounce. Think I'm on 16"
centers.

Sam
"Ken Moiarty" wrote in message
news:v%kre.1667366$8l.1605819@pd7tw1no...
I'm trying to decide whether to go with inexpensive pressure-treated
evergreen wood decking or low cost 1" thick (approx.), radius edge, cedar
(which is must less expensive than standard patio grade cedar decking). I
kind of prefer the cedar option, but I'm unsure about whether it's wise to
go with cedar that is only half the thickness (hence, half the strength)
as standard patio grade cedar. My concern is not about safety per se so
much as it is about structural rigidity, solidness, etc. I don't want it
to feel like I'm 'bouncing on planks' when walking on the deck. Any
suggestions, advice, experiences? Thanks...

Ken




zenboom June 14th 05 10:05 PM




wrote in message
...
On Tue, 14 Jun 2005 11:33:51 -0700, "Sam Wheeler"

wrote:

Done that. 1 inch cedar is solid and has no bounce. Think I'm on 16"
centers.

I'm considering covering a concrete slab I dislike. I was going to use

painted
spf 1x4s on 12" centers on treated 2x4 joists.
Should the 1x4s be fine on twelve in centers? The 2x4 joists are going

right on
the slab so no bounce.


be sure that timber is protected should any water land on that slab.



Heathcliff June 14th 05 10:19 PM

Ken Moiarty wrote:
Chip wrote on 13 Jun 2005 12:40:13 -0700:


CC How thick exactly is this cedar,

It's 5/4.

CC and (very importantly) what's your joist spacing?

I intend to use 12" joist spacing.


Ken


I used the 5/4 cedar on mine with 16" spacing and it was fine. 12"
joist spacing should give an exceptionally solid feel, at least as far
as the planking is concerned. You also need to consider the rest of
the substructu joist spans, posts, and what the posts rest on.
There are plenty of books with guidelines on that if you're not already
familiar. The cedar is nice to work with and you can let it weather or
stain it, either way it should last a long time. You don't have to
worry if it's toxic when you kids drop their gummy bears on it then
pick'em up and eat'em.


J June 14th 05 10:52 PM

"toller" wrote in message
...

Actually it has much less than half the bending strength. Resistance to
bending is proportional to the cube of the depth.


Admittedly it was 30 years ago and things change, but when I took

mechanical
engineering it was proportional to the square. You integrated the

material
multiplied by it's distance from the center; that means squared, no?



Perhaps you didn't do that well in mechanical engineering... :-)

Moment of inertia (I) for a rectangular beam with width b and height h has
been

I = bh^3/12

for as long as I can recall.

And for deflection (d) of a simply supported beam we use the formula

d = PL^3/48EI

Other formulas for bending (canteliever, multiple supports ...) vary, but
all the ones I can recall off the top of my head include I in the
denominator.
Therefore I am certain that I did mean cubed and did not mean squared.

-j



Peter James June 15th 05 04:45 AM

J wrote:
"toller" wrote in message
...

Actually it has much less than half the bending strength. Resistance to
bending is proportional to the cube of the depth.


Admittedly it was 30 years ago and things change, but when I took
mechanical engineering it was proportional to the square.
You integrated the material multiplied by it's distance from the
center; that means squared, no?


Perhaps you didn't do that well in mechanical engineering... :-)

Moment of inertia (I) for a rectangular beam with width b and height
h has been I = bh^3/12 for as long as I can recall.

And for deflection (d) of a simply supported beam we use the formula
d = PL^3/48EI

Other formulas for bending (canteliever, multiple supports ...) vary, but
all the ones I can recall off the top of my head include I in the
denominator.
Therefore I am certain that I did mean cubed and did not mean squared.

-j




Well - you're confusing bending strength and deflection. In your first
post you said:

Quote: Actually it has much less than half the bending strength.
Resistance to bending is proportional to the cube of the depth.

This is incorrect - bending strength is governed by stress, which is
derived from bh^2/6 - the square of depth, as "toller" noted.

But in your second post you introduced deflection:

Quote: Moment of inertia (I) for a rectangular beam with width b and
height h has been I = bh^3/12 for as long as I can recall.

This is correct - for deflection.

--
Peter James

J June 15th 05 09:29 PM

"Peter James" wrote in message
...
J wrote:
"toller" wrote in message
...

Actually it has much less than half the bending strength. Resistance to
bending is proportional to the cube of the depth.

Admittedly it was 30 years ago and things change, but when I took
mechanical engineering it was proportional to the square.
You integrated the material multiplied by it's distance from the
center; that means squared, no?


Perhaps you didn't do that well in mechanical engineering... :-)

Moment of inertia (I) for a rectangular beam with width b and height
h has been I = bh^3/12 for as long as I can recall.

And for deflection (d) of a simply supported beam we use the formula
d = PL^3/48EI

Other formulas for bending (canteliever, multiple supports ...) vary,

but
all the ones I can recall off the top of my head include I in the
denominator.
Therefore I am certain that I did mean cubed and did not mean squared.

-j




Well - you're confusing bending strength and deflection. In your first
post you said:

Quote: Actually it has much less than half the bending strength.
Resistance to bending is proportional to the cube of the depth.

This is incorrect - bending strength is governed by stress, which is
derived from bh^2/6 - the square of depth, as "toller" noted.

But in your second post you introduced deflection:

Quote: Moment of inertia (I) for a rectangular beam with width b and
height h has been I = bh^3/12 for as long as I can recall.

This is correct - for deflection.


Yep, I got a step ahead of myself and forgot I even mentioned bending
strength.

-j



toller June 16th 05 06:04 AM


"Peter James" wrote in message
...
J wrote:
"toller" wrote in message
...

Actually it has much less than half the bending strength. Resistance to
bending is proportional to the cube of the depth.

Admittedly it was 30 years ago and things change, but when I took
mechanical engineering it was proportional to the square.
You integrated the material multiplied by it's distance from the
center; that means squared, no?


Perhaps you didn't do that well in mechanical engineering... :-)

Moment of inertia (I) for a rectangular beam with width b and height
h has been I = bh^3/12 for as long as I can recall.

And for deflection (d) of a simply supported beam we use the formula
d = PL^3/48EI

Other formulas for bending (canteliever, multiple supports ...) vary, but
all the ones I can recall off the top of my head include I in the
denominator.
Therefore I am certain that I did mean cubed and did not mean squared.

-j



Well - you're confusing bending strength and deflection. In your first
post you said:

Quote: Actually it has much less than half the bending strength.
Resistance to bending is proportional to the cube of the depth.

This is incorrect - bending strength is governed by stress, which is
derived from bh^2/6 - the square of depth, as "toller" noted.

Thank you Peter; good to know I am not senile yet.




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