Second Story Floor Joist Design

Ripping the roof off your house and adding a second story addition on top might sound like a drastic means of gaining space but there are various situations in which a total home makeover makes sense.

Second story floor joist design.

1 psf lb f ft 2 47 88 n m 2. Typically the second story floor joists will not only run the same direction as the first floor joists they will also be directly over them. What is the proper placement. So the house dimensions will now be 24 x 13.

Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor. Since the example house we are designing for is 12 feet wide we need to find in the floor joist span table a joist size and centering that can span 12 or wider. As an example consider a room with a floor area of 10 feet by 11 feet 2 inches built with no. A design value table shows that the joists have an fb value of 1 495 and an e value of 1 900 000.

Use a design value table to find the fb value for your floor joists. The widest span in the floor joist span table in part 2 of this tutorial module showed that floor joists can span 17 2 if they are 2 x 12s spaced 12 o c. Maximum floor joist span for no. See the image below for an example of joists spaced 16 on center 16 o c.

Let s expand our house beyond that 17 2 span capability to 24 feet wide. The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example. Live load is weight of furniture wind snow and more. Joist span and spacing is set by your local building code.

When building a house or even a deck it is important to confirm you have the correct joist sizes spans and spacing before you get started. In some cases second story addition plans could be a big money saver in others the real payback is something you can t put a price on. While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length. 1 ft 0 3048 m.

In general terms joists spaced 16 inches on center can span 1 5 times in feet their depth in inches. But larger is not always better when builders are constructing a home or adding a room addition. 2x10 to 15 feet and 2x12 to 18 feet. 1 grade 2 by 6 douglas fir larch joists spaced 16 inches on center.

Dead load weight of structure and fixed loads 10 lbs ft 2. How do i keep them even. The floor joist spacing is the distance between the centers of any two installed joists. Framers construct the second story floor system to match the layout of the main floor system.

A lot of questions revolve around joists when it comes to building a deck. How far apart are floor joists placed. The ability to stay in the neighborhood you ve lived in.