Rafter size
 

Hello,

I'm building a picnic pavilion and was trying to figure out
what size rafters I need. I'm trying to get away with 2X4's 24" OTC.
The building is 10'X16' so the span is 5' on each side. There will be
an overhang of about 2 feet. So the rafter needs to be 7 feet but for
calculations it is only 5 feet (ridge board to top sill plate). Can I
get away with 2X4's? I'm in southwestern PA, zone 5.

Here's the stats for my area:

Code: BOCA 1999
Wind: 80
Ground Snow: 25

Live Load:20
*Roof Snow:18
Exposu B

Acceleration Coefficient (Aa):0.05
*Roof Snow is a calculation based on the Ground Snow.

Thanks,

Sam Hopkins

In article ,
(Sam Hopkins) wrote:

Hello,

I'm building a picnic pavilion and was trying to figure out
what size rafters I need. I'm trying to get away with 2X4's 24" OTC.
The building is 10'X16' so the span is 5' on each side. There will be
an overhang of about 2 feet. So the rafter needs to be 7 feet but for
calculations it is only 5 feet (ridge board to top sill plate). Can I
get away with 2X4's? I'm in southwestern PA, zone 5.

Here's the stats for my area:

Code: BOCA 1999
Wind: 80
Ground Snow: 25

Live Load:20
*Roof Snow:18
Exposu B

Acceleration Coefficient (Aa):0.05
*Roof Snow is a calculation based on the Ground Snow.

Thanks,

Sam Hopkins

What does your building code say? You did do that research, correct?

A rafter will only be 7 feet long with a 5' span and a 2' overhang if it is
a flat roof. Any slope will add to the length.


"Sam Hopkins" wrote in message
om...
Hello,

I'm building a picnic pavilion and was trying to figure out
what size rafters I need. I'm trying to get away with 2X4's 24" OTC.
The building is 10'X16' so the span is 5' on each side. There will be
an overhang of about 2 feet. So the rafter needs to be 7 feet but for
calculations it is only 5 feet (ridge board to top sill plate). Can I
get away with 2X4's? I'm in southwestern PA, zone 5.

Here's the stats for my area:

Code: BOCA 1999
Wind: 80
Ground Snow: 25

Live Load:20
*Roof Snow:18
Exposu B

Acceleration Coefficient (Aa):0.05
*Roof Snow is a calculation based on the Ground Snow.

Thanks,

Sam Hopkins

Robert Morien wrote in message ...
In article ,
(Sam Hopkins) wrote:

Hello,

I'm building a picnic pavilion and was trying to figure out
what size rafters I need. I'm trying to get away with 2X4's 24" OTC.
The building is 10'X16' so the span is 5' on each side. There will be
an overhang of about 2 feet. So the rafter needs to be 7 feet but for
calculations it is only 5 feet (ridge board to top sill plate). Can I
get away with 2X4's? I'm in southwestern PA, zone 5.

Here's the stats for my area:

Code: BOCA 1999
Wind: 80
Ground Snow: 25

Live Load:20
*Roof Snow:18
Exposu B

Acceleration Coefficient (Aa):0.05
*Roof Snow is a calculation based on the Ground Snow.

Thanks,

Sam Hopkins

What does your building code say? You did do that research, correct?

Lots of things like that have been built with 2x4 rafters. The only
thing (other than local code) that I see wrong with them is the
weakness caused by cutting the birdsmouth. That effectively reduces
the part supporting the 2' overhand to a 2x2 or 2x3. Of course if you
use metal brackets with no birdsmouth - no problem.

Correction to your figures before you buy the lumber. Your rafters
will be longer than 7' if there is any rise at all to your roof.

Harry K

On Fri, 8 Oct 2004 21:19:28 -0400, someone wrote:

A rafter will only be 7 feet long with a 5' span and a 2' overhang if it is
a flat roof. Any slope will add to the length.

He'll be buying 8 foot anyway, I presume.

-v.

On 10 Oct 2004 07:01:34 -0700, someone wrote:

... buys at a
real lumber yard where they will cut them for him....

?? I think of a "home center" as someplace that cuts boards for
customers, and a "real lumber yard" as someplace that sells stock
sizes to contractors who have their own saws and cut their own
lengths!

-v.

On 12 Oct 2004 06:29:00 -0700, someone wrote:


Wrong. I have never seen a 'real' lumberyard that didn't cater
heavily to homeowners/handymen. Eveyone I do business with is more
than happy to cut to size for me.

Oh, my local lumberyard has a sign on the wall "cuts $1 ea."; they'll
do it. But as I stand at the counter, I see that the overwhelming
majority of the quantities sold are stock lengths - often full bundles
or pallets - that the users will cut themselves.

My personal observation is that most customers of real lumber yards do
NOT have their wood cut for them, even though the yards will do it for
the occasional customer who asks for it.

I don't recall ever having a lumber yard cut a board or even a panel
for me, though its been a lot of years, maybe I did sometime way back
whenever.

-v.