Thought some might find this Residential Construction Guide (http://www.mcvicker.com/resguide/page000.htm) useful. Found it recently when investigating upcoming master bedroom ceiling project.

[EDIT] Use at own risk - old codes

Cheers,
Mark

good find but 1994 codes? I wish it was updated. Fairfax County uses 2003 codes.

Yeah - I know but best source I've found without buying the new codes

Unfortunately, in addition to being 1994, they are UBC codes. There are significant differences in today's IRC.

This link still has some good information, but don't rely on it too heavily.

Code Check is a great resource for code and building practice information. You can get a Code Check book less than $20 and it is very well done with lots of illustrations and explanations.

Mark, just a heads up, you referenced the ceiling joist span table from this document in another thread It was for Douglas fir if I remember. You should be aware that the span tables are different for Southern Yellow Pine which is most of what we get at Home Depot in sizes larger than 2x4. You can get fir in 2x4s but it is not the Douglas fir.

I've found the tables on-line in the past for different species.

Ah Ha - good to know - just found a site that has Southern Pine tables.

Looks like its stronger and you just saved me some time & money :D

Double check, I thought it was the opposite.

Looking here (http://www.southernpine.com/pdf/table17.pdf) for Souther Pine and here (http://www.mcvicker.com/resguide/page013d.htm) for Douglas Fir

SP No2 2x6 on 24" oc the span is 15' 6"
DG No2 2x6 on 24" oc the span is 11' 6"

I've got a span of 20' to deal with and was designing at 2x10 on 16" oc, with Southern Pine (need to check grade) I could use 2x8 on 24" oc.

OK I went and grabbed my reference book "Visual Handbook of Building and Remodeling..Professional edition".

For ceiling joists with no attic storage, 10 PSF Live, 5PSF dead.

for 2x6s 16 inch on center

Douglas fir No2 - 11'-3"
Hem-Fir (what HD sells) No2 - 10'-6''
Southern Pine No2 - 11'-3''

2x8s 16 OC

DF 17-8
HF 16-6
SP 17-8

So I was wrong SP is the same as DF.

Want me to look anything up?

HMMMM. I just looked at my book and the tables were published by the Canadian Wood Council. Wonder if they selected a particular standard that made the SP look not as good as the Southern Pine Council. Ponderous man, Ponderous.

Given that the SP council rates SP so well Now I'm thinking you need to be very careful in making sure that is what you are getting. Anything marked SPF can Actually be spruce,Pine,Fir

Wow - everything is so conflicting :( how is a poor DIY'er supposed to sort thru this crap.

According the the Southern Pine span table (which is also specified for ceiling joists with no attic storage, 10 PSF Live, 5PSF dead) a 2x8 can span from 18'9" to 24'3" depending on the grading of the lumber.

This is based on 2002 SPIB Standard Grading Rules for Southern Pine Lumber.

Out of curiosity what is the date of the code your book is based on?
[Edit] I see from last post ^^^ Canadian Eh :D Maybe there added some Steroids to the US SP :D Think I'll see if I can get exact type of wood from HD

My book says the only thing in SP 2x8s that can go 20 is Select Straight at 12 inches OC.

No2 24 inches OC is rated at 15'-6"

book published 1998. Canadian Wood Council referenced 1996.

Knowing that the quality of wood is generally declining due to fast growth versus old growth issues it really looks like the old saying "they don't build them like they used to" is really true.

Southern Pine (Loblolly, Longleaf, Shortleaf) is mostly turned into pressure treated wood and timbers. All of the PT dimensional lumber at my HD is SYP #2. If you want to use the stregth of the Southern Yellow Pine, you might think about using PT for your longer spans.

As you surmised, everything else that's not one of the "Southern Pines" is sold as SPF, and almost always is non-treated. The spruce (S) is mostly Black and White Spruce, the pine (P) is Jack Pine, Lodgepole Pine, and Red Pine. The fir (F) is Balsam Fir, but not DouglassFir, as you noted previously.

Mark,

Have you looked into any of the I-Joist products? You can usually get the longer spans easier with them than you can dimensional lumber. They used to be more costly, but they are actually selling for the same or less than standard lumber right now.

Chris - not yet. Will look into those onec I've checked what HD's lumber is and what its span limits are.......I'll definatly want to go above code thou. Seen too many Mike Holmes shows just to do code on structures like this.

My master bed is circa 20'x20' and changing the curent vaulted ceiling into something like this:

http://www.electronichouse.com/images/uploads/meadeBR_artUP_300.jpg

The 1st tier will be 30" wide with 2nd about 24" leaving 10' in the center. So I need to have the main joists on multiple levels.

I was at HD and did a walk down the lumber aisle. Of course I quickly realized that what I had been thinking was southern yellow pine is actually SPF. They also had Hem-Fir in various sizes but the most important issue is that the longest I spotted in any size was 16 ft.

Mark, You may want to give Tart lumber in Sterling a call and see what they carry.

Mark, You may want to give Tart lumber in Sterling a call and see what they carry.

Yeah, I noticed that HD max length was 16'.

I'll be going down to Tart early next week, find out what their lumber is and also see how their I-beams compare.

Chaperoning a 7th grade field trip to National Zoo tomorrow :eek: and off to meeting in Philly Friday :(

Chaperoning a zoo trip? Good luck with that :)

Instead of setting joists at varying heights, it would actually be easier to set all the joists at the highest point you want the ceiling and then build the two step downs as soffits. That is how we frame the tray ceilings like the one you have a picture of.

Good luck with the project.

found this interactive span calculator from the AMERICAN wood council

http://www.awc.org/calculators/span/reversecalc/reversecalc.asp?feet=20&inches=0&species=Spruce-Pine-Fir&member=Ceiling+Joist&deflectionlimit=L%2F720&spacing=16&liveload=10&snowload=-1&deadload=5&wet=No&incised=No&submit=Calculate+Span+Options

.

On second thought, that wouldn't work either. A beam with a 20 foot span wouldn't be able to support the joists.

I think sistering the joists might be the best bet.

The spans for ceiling joists are listed in the IRC. From the 2003 version, assuming no storage above and L240 you can span 20' with:

2x8 at 12oc - any species
2x8 at 16oc - doug fir down to #2, hem-fir, southern pine down to #2, spf down to #2
2x8 at 24oc - doug fir down to #1, hem-fir ss, southern pine down to #2

HTH,

Tim