LumberJocks

Attic load limit

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by slick3 posted 12-18-2012 07:21 PM 1191 views 0 times favorited 12 replies Add to Favorites Watch
View slick3's profile

slick3

2 posts in 709 days


12-18-2012 07:21 PM

I have a garage 24×24 in size. Running through the center, I have three 2×12 x 24 for my support beam. My question is, does anyone know how much weight I can store in my attic? The attic floor is 1/2” plywood resting on 2×8 ceiling joit on 16” centers.


12 replies so far

View grfrazee's profile

grfrazee

341 posts in 863 days


#1 posted 12-18-2012 07:38 PM

I believe the IBC specifies a live load limit of 30 psf for occupied attics. If yours was designed to be unoccupied, that won’t be the case.

While I am a structural engineer, I am unlicensed, and cannot give any guarantee of accuracy without seeing your garage, the plans, and a capacity calculation for the space. Don’t take anything I say as advice in the matter, since I have no legal backing whatsoever.

Anecdotally, when I was growing up, we had a one-car garage. My dad would stack stored lumber in the rafters, though he would probably keep it below 4” thick of wood stacked in one area. This is in southeast Wisconsin, with a 12/12 pitched roof, and plenty of snow. As far as I know the old garage still stands.

Play it safe. You will probably be fine putting a few boards up there, but don’t expect to use it as a hoist point to get the engine out of your car.

-- -=Pride is not a sin=-

View Tennessee's profile

Tennessee

1523 posts in 1238 days


#2 posted 12-18-2012 07:39 PM

I don’t know, but I bet it is a lot lower than you think. 24’ is a heck of a span. Any chance of adding two 4X4 support beams at the 8 and 16 foot marks of the 24’ triple beams? That would make a huge difference in my mind.

-- Paul, Tennessee, http://www.tsunamiguitars.com

View a1Jim's profile

a1Jim

112544 posts in 2301 days


#3 posted 12-18-2012 07:44 PM

View Sarit's profile

Sarit

493 posts in 1863 days


#4 posted 12-18-2012 10:12 PM

For my garage remodel, I’m replacing a 14”x4”x24’ doug fir beam w/ 2 16”x5.5”x19’ GluLam beams running perpendicular. I spec’d 40psf live load to my engineer.

Comparatively, I don’t think triple 2×12’s are gonna be able to take that much weight with a 24’ span in both directions. You also don’t want the beam bearing over your garage door header, which was the case in my garage.

View a1Jim's profile

a1Jim

112544 posts in 2301 days


#5 posted 12-18-2012 10:18 PM

Some else can help with load calculations is your local truss company.

-- http://artisticwoodstudio.com Custom furniture

View Grumpymike's profile

Grumpymike

1153 posts in 1039 days


#6 posted 12-18-2012 10:46 PM

Using 2X8 joist at 24’ in an unsuported span exceeds maximum horiz. span limits.
I don’t think that we are given all the facts here. Do you have a center post or two in that 3- 2×12×24 beam?
If so you now have 12’ spans; and with a fink truss your vertical load limits go way up.

-- Grumpy old guy, and lookin' good Doin' it. ... Surprise Az.

View teejk's profile

teejk

1215 posts in 1408 days


#7 posted 12-19-2012 12:07 AM

using engineered trusses? then probably no weight at all.

View Sarit's profile

Sarit

493 posts in 1863 days


#8 posted 12-19-2012 12:20 AM

Grumpymike,
I think the 2×8’s will run perpendicularly across the centrally located triple 2×12 beam. Essentially splitting the 24’ span in half.

View Grandpa's profile

Grandpa

3193 posts in 1399 days


#9 posted 12-19-2012 02:07 AM

2×8’s used as floor joist will span about 14 feet. I usually recommend attics not be used for storage. We all know how well this works but you have to try.

View Granddaddy1's profile

Granddaddy1

181 posts in 925 days


#10 posted 12-19-2012 02:24 AM

Way too much missing information to give sound advice. A tripple 2×12 beam spanning 24’ is probably maxed out carrying your 2×8 joists. Not to mention the 3 ply beam is probably bearing on a garage door header that will receive the translated load. We’ve learnedly a lot in the post Hugo/Andrew/Katrina era that was never thought about before regarding residential structures, so unless your home is newer I’d strongly suggest consulting a professional engineer in your area. The money you spend will be cheap compared to the potential consequences.

-- Ron Wilson - maker of fine firewood!

View JoeinGa's profile

JoeinGa

3525 posts in 731 days


#11 posted 12-19-2012 02:39 AM

Note to self ... Remind me to never let you guys see what I have stacked in the rafters of my workshop :-) :-)

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View hhhopks's profile

hhhopks

564 posts in 1101 days


#12 posted 12-19-2012 02:40 AM

A structural engineer should able to answer your question but you need to provide the proper information.
Can you provide some photos and supplement it witch sketches and data?

I am not a SE myself but having good information will make it a lot easier for someone to help you.

-- I'll be a woodworker when I grow up. HHHOPKS

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase