Wood Framing
December 11, 2013In many parts of the country, for residential projects and some commercial projects, wood is the preferred material. In the southeast, southern yellow pine is a preferred species in many applications, however, its limitation is how straight (or rather, un-straight) it can be. As lumber mills put out lower quality lumber, SYP (southern yellow pine) just gets more crooked, sometimes splitting on site because of knots that are not visual graded out of the production line.
Our project below is being built on spruce, No. 2 or better. Take a look at how straight the framing is (aside from the rough carpenter’s good work of erecting the structure plumb and true):
There are several reasons why this is preferred:
1) It’s not just framing. Straight, plumb and true framing is the foundation for other structural and finish materials. If the framing is crooked, the sheathing doesn’t go on right. If the framing is crooked, drywall requires floating out or other labor intensive “fixes”. And it goes down the line: Exterior siding, interior millwork (base boards and/or crown mouldings), tile and other finishes get that much more difficult when the framing is done sloppily. When its done well, subcontractors that come after the framer are able to do their job without having to shim, float and otherwise waste time prepping their install surface.
2) Structural integrity is better when corners touch properly. Crooked studs make this hard to do.
3) You may not realize it but when the plumber and the electrician come to site in order to run their services through your project, they make alot of holes. Building code doesn’t allow more than a certain percentage of each stud to be bored out or notched, depending on its location in the wall and proximity to other reduced capacity studs. So spruce is better than SYP because when you notch or bore, you have a stud that holds together better than SYP, with all its knots. General, SYP is a stronger wood than spruce, but with the downgraded quality that is being put to market, SYP can still cause more problems than its worth.
4) Straighter lumber enables a rough carpenter to work with a more dependable material, enabling faster and (most of the time) better work.
The photo above shows a studded truss over an interior shear wall. Without the studded truss (which has sheathing all the way up to the underside of the roof deck) the shear forces acting on the structure are not properly transferred from roof to footing. Note that the trusses in the above image have not yet been properly fixed, and are not in their final position, although they were properly braced for erection.
Corners: no, not football. At framed corners, spruce makes a straight, strong corner. Although I’d prefer to see a California corner, which allows for better installation of insulation, this is a well-built corner.
Headers: at the exterior wall openings, box headers are great because not only are they strong, you can fill them with loose fill insulation, or just make a rigid insulation sandwich inside the box. This helps provide a thermal break that the traditional header (3 pieces of lumber nailed side by side in a 2×6 wall) does not.
Moving to Florida from New York, I expected lots of CMU (concrete masonry units) in small project construction, but my experience in Northeast Florida is that wood is preferred, possibly because we have lower wind design requirements than other parts of the state that get most of the hurricanes and high winds. CMU is more expensive, and wood framing is well-known and well-used in the area.
Now we just need to put more CLT (cross-laminated timber) in projects like this and larger.