better outdoor living at home spring

Nominal vs. Actual Sizes of Lumber

Dimensional lumber is used to build houses, porches, decks, pergolas, and so on. Before building an outdoor project know the actual sizes of lumber.

Dimensional lumber is used to build great features for your yard.

Most people are perhaps acquainted with typical lumber sizes, like the 2×4 or the 2×6. These are the nominal sizes, or names, of the lumber. When you go to the home improvement center or lumber yard to buy wood for a project, you look for those sizes in whatever lengths you need. If you take a tape measure and check the dimensions of say, a 2×4, you’ll see that it actually measures 1 1/2” by 3 1/2″. This difference is known as the nominal size (2×4) vs. the actual size (1 1/2” by 3 1/2″). The actual size of dimensional lumber is always smaller than its nominal size.

The difference in the size comes from when the timber logs (tree trunks with the branches removed) are sent to a lumber mill where they are first cut into standard sizes, like the 2×4. At this point in the milling process, the lumber would be referred to as rough sawn lumber (there may even be some bark still on it) and its measurements would really be 2” by 4”. Rough sawn lumber has a very rustic appearance, which is a desirable look for some projects.

Further processing at the mill involves putting the lumber through a planer to get the smooth, also called ‘dressed’, surfaces. This processing of the lumber produces the dimensional lumber that you see at the stores and the lumber yards. After it is planed, the piece of lumber no longer has its nominal dimensions, for it has been reduced in size. It is stilled referred to by its nominal size, such as the 2×4, but its actual size is now 1 1/2” by 3 1/2″. Nominal and actual sizes of lumber are construction standards in the building industry.

When building a project, one needs to know there is a difference between the nominal and the actual sizes of lumber.

Typically, the lumber in the store or lumber yard is planed (dressed) on all four sides and is denoted as S4S. If only two sides are planed, it is denoted as S2S. Dimensional lumber is usually produced from softwoods, such as spruce, pine, fir, cedar, and redwood. It is typically used for floor joists, deck joists, beams, arbors, fences, roof rafters, stair stringers, wall framing, decking, and posts. It is also used for building things like work benches, potting tables, benches, and planter and window boxes.

The following table shows the nominal size and the actual size of the more commonly used sizes of lumber:

NOMINAL             ACTUAL
1 x 2                3/4″ x 1 1/2”
1 x 3                 3/4″ x 2 1/2”
1 x 4                 3/4″ x 3 1/2”
1 x 6                 3/4″ x 5 1/2”
1 x 8                 3/4″ x 7 1/4”
1 x 10               3/4″ x 9 1/4”
1 x 12               3/4″ x 11 1/4”
2 x 2               1 1/2″ x 1 1/2”
2 x 4               1 1/2″ x 3 1/2”
2 x 6               1 1/2″ x 5 1/2”
2 x 8               1 1/2″ x 7 1/4”
2 x 10             1 1/2″ x 9 1/4”
2 x 12             1 1/2″ x 11 1/4”
3 x 6               2 1/2″ x 5 1/2”
4 x 4               3 1/2″ x 3 1/2”
4 x 6               3 1/2″ x 5 1/2”
6 x 6               5 1/2″ x 5 1/2”



Related Posts Plugin for WordPress, Blogger...

(example: DIY projects, decks, steps, outdoor decor)

Copyright © 2009 - 2017 Better Outdoor Living at Home / Begin with a Sunny Outlook All Rights Reserved
All designs, images, and content on this website are the copyrighted property of Better Outdoor Living at Home/begin with a Sunny Outlook