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View Full Version : Douglass Fir vs. Spruce vs. Framing Lumber



Jonathan Szczepanski
10-25-2005, 3:02 PM
For my workshop, I was planning on using 2x12x20' Douglass Fir at 12" on center to span the second floor. The problem I am having is that I can't find anyone that sells Douglass Fir in that size. I have only found Spruce and "framing lumber in 2x12x20'

Do I need to worry about the difference between Douglass Fir, Spruce, and framing lumber? Will any of the three work?

You can see the plans at: http://www.theworkshopproject.com/plans.php

Thanks in advance.

Joe Pelonio
10-25-2005, 4:17 PM
Great looking plans, I hope you'll post photos as you go along on the project.

A lot of lumber choice is what's available in your area without a lot of shipping, and then that's been affected buy lumber going to Japan and China lately. Here in the NW we have "Hem-Fir" which can be either douglas fir or hemlock. We don't have spruce. When they say "framing lumber" it could be anything. More important is the grade.

For framing, select structural and No. 1 gradeis best. Cheaper grades arenīt as strong, straight or easy to work with. If you pick thru you can get decent pieces by inspecting them closely, but some places if you order and have it delivered won't let you pick it.

Vaughn McMillan
10-25-2005, 5:00 PM
Joe, Jonathan has been sharing the ups and downs of his project for quite a while. It's in this thread:

http://sawmillcreek.org/showthread.php?t=14847

- Vaughn

Richard Wolf
10-25-2005, 6:23 PM
A 20' span 12" oc is not a problem for any framing material except #3 grade. So just be sure the material is SS, #1 or #2. SS of course, the best.

Richard

Jason Roehl
10-25-2005, 8:54 PM
Around here, studs and other non-spanning lumber are typically SPF, or Spruce/Pine/Fir, meaning it is any of a multitude of "whitewoods", as they are known elsewhere. Lumber for floor joists, if not engineered i-joists or web joists are pretty much always SYP--Southern Yellow Pine, which is denser/heavier and harder than SPF, and is also what our treated lumber supply is made from. From what I've seen in on-site stain/finish work, Douglas Fir is probably pretty close to SYP in terms of strength and hardness, but it's not very common here.

I personally wouldn't use any of the SPF for floor joists (maybe for roof joists, though), as most of it isn't necessarily straight-grained and knotty, both of which are characteristics which can weaken it significantly, of course.

Just my local experience.

Richard Wolf
10-25-2005, 9:19 PM
Here is a link to floor joist spans.
www.awc.org/Publications/update/WFCM2001FullPage.pdf

Richard

Jim Becker
10-25-2005, 9:47 PM
Have you considered using the manufactured "I-beam" beams? (sorry, I forget the real name for them) They are really great for these spans and are also lighter in weight...which if I remember from your thread could be useful to you in getting them "up top" of the walls. My shop building is built with them supporting the second floor and they are strong and stiff.

Jonathan Szczepanski
10-25-2005, 11:02 PM
Here is a link to floor joist spans.
www.awc.org/Publications/update/WFCM2001FullPage.pdf (http://www.awc.org/Publications/update/WFCM2001FullPage.pdf)

Richard
Richard -

What a great find. Thanks!

Jonathan Szczepanski
10-25-2005, 11:06 PM
Have you considered using the manufactured "I-beam" beams? (sorry, I forget the real name for them)
Jim -

I thought about maufactured I-beams (I don't know the name either), but I thought the cost would be higher. Plus I don't know how I can attach them to the rafters. Are they built out and then nailed to the rafters? How is the build out attached to the I-beam? Nails? Glue? both?

Too many questions that I couldn't find the answers to.

Jason Roehl
10-25-2005, 11:41 PM
Have you considered using the manufactured "I-beam" beams? (sorry, I forget the real name for them)

Generically, I have always heard/read them referred to as "I-joists". I don't recall the names of any of the manufacturers, though.

Michael Perata
10-26-2005, 1:01 AM
Tru-joist & Boise-Cascade are probably the biggest names in the I-joists.

In a 2X12X20 DF application, the solid wood will probably be substantially higher than an I-joist, and you may be able to downsize the I-joist for additional cost savings.

The installation of I-joists, above the plate, is nearly the same as with wood members. Just remember to also buy rim joists from the same manufacturer so the depth of the joist is always uniform.

Jonathan Szczepanski
10-26-2005, 8:37 AM
Here is a link to floor joist spans.
www.awc.org/Publications/update/WFCM2001FullPage.pdf (http://www.awc.org/Publications/update/WFCM2001FullPage.pdf)

Richard
Richard (and all) -

I looked around the American Wood Council's wesbite, www.awc.org (http://www.awc.org), and they have online calculators that can tell you what size you need or what span you can cover. Pretty neat. This is what the internet is about.

Maximum Span Calculator for Joists & Rafters (http://www.awc.org/calculators/span/calc/timbercalcstyle.asp?species=Spruce-Pine-Fir&size=2x12&grade=No.+2&member=Floor+Joists&deflectionlimit=L%2F360&spacing=12&wet=No&incised=No&liveload=40&snowload=-1&deadload=10&submit=Calculate+Maximum+Horizontal+Span)

Span Options Calculator for Joists & Rafters (http://www.awc.org/calculators/span/reversecalc/reversecalc.asp)

Phil Phelps
10-26-2005, 1:08 PM
Generically, I have always heard/read them referred to as "I-joists". I don't recall the names of any of the manufacturers, though.
Check your lumber yard for Glu-lam beam.

Jason Roehl
10-27-2005, 9:14 AM
Check your lumber yard for Glu-lam beam.

As near as I can tell, Phil, Glulam is used more in the context of a supporting beam, not as floor joists. I'm sure you probably could use them as floor joists, but that would probably be prohibitively expensive.

For those that don't know the difference, an I-joist is basically two pieces of yellow pine (or similar), maybe 2x2 or 2x3, laid flat, with a vertical section of OSB between them, to form the shape of an "I". On the other hand, a 4"x12" Glulam would look like a stack of 6 2"x4"s glue together by their faces, running parallel.

I-joist:
http://www.apawood.org/level_b.cfm?content=prd_joi_main

Glulam:
http://www.rosboro.com/glulam.asp

Rob Russell
10-27-2005, 10:45 AM
Glu-lams or microlams are overkill for the floor joists. These are the things that look like plywood beams - full width. They are normally used as supporting beams or applications where you need a very stiff floor.

The "I-beam" style joists are far less expensive than the glulams. They aren't as stiff and are cheaper. They are stiffer than normal dimensional lumber.

There is a 3rd option - floor trusses. These are open web trusses - made from 2x4's. The top and bottom chords are flat 2x4's with a bracing web of 2x4's that zig-zag back and forth between the top and bottom. They look a little like those steel bridges with zig-zag trusses. One of the nice things about floor trusses is you can specify how strong (weight load) and/or stiff (vs. bouncy) you want them. I used floor trusses for the floor in our addition because it's all tile floors and I needed it to be very stiff.

Rob Russell
10-27-2005, 10:47 AM
On the other hand, a 4"x12" Glulam would look like a stack of 6 2"x4"s glue together by their faces, running parallel.


Jason,

A Glulam looks like a beam made of plywood. It's not a stack of 2x4's.

I can post pictures of both microlam/glulam beams the the floor trusses when I get home.

Rob

Jason Roehl
10-27-2005, 7:26 PM
Jason,

A Glulam looks like a beam made of plywood. It's not a stack of 2x4's.

I can post pictures of both microlam/glulam beams the the floor trusses when I get home.

Rob

Rob, check the website I posted for glu-lams. I have seen both--some that look like 6000-ply plywood, and some that look like a stack of 2x4s or 2x6s. The website I linked to shows the 2x4 type.

John Shuk
10-27-2005, 8:19 PM
Floor trusses are nice too because it is easy to run pipe abd electric through the open spaces. If you are going with solid wood I would have to lean toward doug fi. My house is mostly spruce and I think there is alot more movement with it. Doug fir is a better spec imho.

Rob Russell
10-28-2005, 6:13 AM
Well Jason - this proves you do learn something every day. I didn't know glulams were made that way. I wonder which is stronger - the stacked 2x4/6 variety or the ones I'm used to which are like plywood.

I've attached a picture of the glulam beams supporting our addition and the floor trusses.

Michael Perata
10-28-2005, 9:35 PM
Rob

The picture on the left appears to be a LVL (Laminated Veneer Lumber) beam.

LVL is typically made by gluing up the veneers in a vertical fashion. GluLams are typically made by gluing the pieces horizontally.