remodeling for geeks

The majority of material used in residential construction that define your walls, floors and roofs are sheet goods (plywood, sheet siding, underlayment, sheetrock, paneling) are made in 4×8′
sizes. The basic building blocks of wood
framing, regardless of what the outside of your house is covered with
are 2×4” vertical framing members. They are 16 inches on center. (In
probably 99% of cases)

16” On Center is the standard measurement for spacing  in wood frame
construction.  This system has been around since about 1833 . 2×4” framing members were developed as a result of a building boom and the ability to cut and use smaller framing members faster, than post and beam, which required a longer drying and seasoning period.  16” centers were developed as the interior finish system at the time was plaster and lath, lath being made 48” long, and 16” centers allowed for 4 attachment points.

With industrialization, and the availability of sheet goods most notably plywood and drywall for enclosing space for living, working with building material manufacturers, builders, engineers and governmental agencies on local, and national levels, building codes were developed.

Building codes are minimum requirements for construction. Codes serve two purposes, stability and safety. Stability so that under most circumstances, it will not fall down. Safety in requiring a minimum structure that will not burn down in a flash, and provide a way for you to get out of the house in case of fire or flood. This is why any room in your house of a certain size with an exterior wall most notably  bedrooms, have a minimum window size.  Regardless of the construction of your house, at one point, it was built to these minimum standards. Unless it is really old. This is also why there are a lot of ‘standard’ sizes for doors and windows.

This also accounts for cookie cutter houses in ‘divisions’ and ‘developments’ A lot of this construction was based on a profit motive rather than an design or environmental perspective. There is a small amount of environmentalism in these houses, but it is limited to the builders ability to enclose the house with the smallest amount of material for a given area.

Most wood frame construction is built with 2×4” studs, which are not. 2×4’s used to be 2×4”, but over time as construction techniques and materials became more sophisticated today’s 2×4 is actually 1 1/2” x 3 1/2”. Other 2x materials are subsequently smaller, 6”-5 1/2” and so on. Sheet goods like plywood and drywall are as stated.

I mentioned previously in talking about tape measures, that one of the notable features was 16” center markings. This is a 2×4” 16” on center.

Note that the edge is 15 1/4” on the left and the right should be 16 3/4”, which normally it is but this shot was taken with a old dry stud. Material shrinks as it gets old and dries out.

Unless your house is a bazillion dollar award winner, built out of weird materials, your walls are
built on 16” centers. It may be 1×2 furring strips to 2×4-6 to something else, but they are there.

Being able to find your studs and their centers is very important especially if you are only looking for a place to hang a heavy picture, mount cabinets, or doing wall trims like chair rails or plate rails.  If you are not doing a to the frame demo, finding them is not as easy as scanning
a wall with a stud finder or banging holes in your walls with a 16d
nail. I have the first but use the latter, as I am old school.

The first thing to take into account is your house is laid out from the exterior. This is a simple illustration of a typical layout. Not to scale but an illustration.

In an ideal world you would be able to measure from your inside corner around 12”(12” being the difference between the outside corner minus the 3 1/2” stud and the 1/2” – 5/8” drywall) and hit your first stud.

Heh heh, silly remodeler…. Let me give you a live fire exercise from a recent project.

How Centers are Made

This is Art Room Expansion Project.

This is the original wall stripped of the sheathing. It is 16′ across. Outside.

Looking at the right side is the corner which is made of two studs and blocking. This is a typical outside corner.

Ignore the white outlet, it is temporary. The next stud 16” on center is the one with the outlet hole in the drywall. The next 16” o.c stud is actually 2 pieces above and below the window opening. The next full stud is the third stud on the left side of the right window opening. Note that below and above the window openings, the 16” o.c spacing is maintained. If it looks like there is a lot of extra material in this wall, you are wrong. There is no extra material due to the design of the wall with the two windows and the air conditioner hole in the center of this wall. The sistered studs on either side of the a/c unit carries the weight of the roof to the foundation, and are needed.

The Artroom Expansion is 16′ wide by 14′ deep. This was a result of designing to maximize the room while minimizing waste of siding materials. Drywall is cheaper than siding.

This is the north wall.

Looking at this wall from the right you see that our 16” o.c. layout is interrupted by the window opening as we are reusing the windows we removed from the end wall. The reason we built it like this is to not have the window obstructed by the door which will swing into this room. We also wanted to maximise the wall area beyond the window.  Because the height of this room is 7′ inside, the header is next to the top plate, no cripples are needed above it, but they are needed below the sill to maintain our 16”o.c. spacing to have nailing for the siding. The 14′ length means that I will use 3 1/2 sheets of siding with no waste as the 1/2 sheet will go on the corner of the south wall.

Here is the East wall.

The 16” o.c. spacing is clearer here, but as you can see in the photo, this is a bit more symetrical  as our window is dead center in this wall.

This is the south wall.

Here our framing is clearer, but is a little off center as we are centering the window to the inside, (our inside dimension is 13′ 8 1/2” rather than 14” because of the back wall taking up 3 1/2” of space) our framing has a corresponding shift.

Complicating this are the king studs, which are the studs sistered next to the trimmers that are the short vertical studs that are framing for the window openings, above and below the sill plate, which is the bottom horizontal framing member at the window opening.

Finding your centers

One way to start the process is to look for electric outlets on the wall. Unless you live in an architectural digest house, electric boxes are always nailed to a stud. Removing the cover plate and peering inside, you may see which side of the stud the box is attached to. You may want to use a level and establish a plumb line further up the wall in the kitchen/bathroom so your wood pecker probing will be hidden by your cabinets.

Your first set of holes should be close enough to find the edges of the stud so that you can more accurately measure your 16” centers. So finding your centers especially with the walls intact is not impossible but does require a little thought and maybe some spackle.

You can do this.

Trust me, nothing says oops like your cabinets crashing to the ground or that big mirror you found at ReStore or on Craigslist, becoming a safety hazard.