Thursday, August 6, 2009

Floor Framing - "A Failure to Plan is a Plan to Fail"

You can not just jump out of the truck and start bending nails! Always approach floor framing with the same careful planning and care as used in any other carpentry task. Study the blueprint carefully and make note of the location of staircase openings, cantilevers, in floor beams, and concentrated loads from above. My theory is to build from the roof down. Of course, I do not mean build the roof first. Look at the roof plan (a few days ahead of time) and take note of any concentrated loads, varying wall heights, cathedral ceilings, etc. A good carpenter knows these things before placing sill plates and beams.

I like to begin by having two of the guys go around and snap lines on the perimeter of the sill plate whatever the thickness of the rim joist is to speed up the process of framing the floor. All floor joists can be set to this line eliminating the need to pick the rest of the floor joists up and over the box sill. I realize there are a lot of carpenters out there who will disagree with this method and prefer to install the rim joist first. Over the years I have done it both ways, and feel if you tighten sill plate nuts only finger tight this method works best, especially on the second floor because you have 3 1/2" to walk on instead of 2".

You are usually better off beginning your layout from the longest straightest run that you have. If you have enough time and can still keep all the carpenters busy, I find it best to layout the staircase openings first to avoid the possibility of the apprentice placing material in my way. Sometimes this is not possible, in that case you should start laying floor joists on the opposite side of the staircase.

If you have access to a Pettibone or Lull it can be the best laborer you ever had, even a small skid steer or backhoe with forks is much better than your back. You are however forced to use what you have, so at the very least have your material supplier dump the load in the best spot for your situation.

Once you have the staircase and any cantilevered floor joists marked out begin by crowning and marking floor joists. Think about the situation, right or left-handed person, best direction for rolling the floor joists, etc. Locate the joists so that they are all crowned in the same direction, close enough to the mark so all you have to do is roll them up and nail in place. When nailing on the end where the rim joist goes a lot of people put to many nails on the end and split them out, this reduces bearing on the sill plate and invites a floor squeak which is nearly impossible to locate and fix later. Look at the grain pattern on the joist and locate nails accordingly, one or two well placed nails are plenty as the joist will be nailed to the box sill later. When working the middle I find it best to, walk the beam, nail on the opposite side of where the opposing floor joist will be sistered up. Always work in the direction that is best for the man in the middle, because they will be slowest, dragging an air hose and nailer, especially if forced to work backwards. Always remember In carpentry a little planning goes a long way towards greater efficiency, not to mention your poor aching back.

The author of this article has 29 years of experience working in the highly competitive housing market of the west and southwest suburbs of Chicago as a carpenter. His job titles have included Master Roof Cutter, Apprentice, and everything in between. Most of his experience is in the high end custom home marketplace, including all aspects of fine homebuilding, from footings to ridge cap. His website contains more information on House Framing Carpentry, Pythagorean Theorem, Framing Square and Roof Framing

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