Floor Joists Are Typically What Size In Residential Construction. As a rough guide with 2 external walls use 75mm polyurethane. Given that 2x8s are actually 1-¾ inches wide it works out to be 14-¼ inches between each joist.
The floor joist spacing is the distance between the centers of any two installed joists. A 2x8 up to 12 feet. Floor joists spaced on regular intervals span the areas between supports such as walls foundations girders and beams.
You should check with your local building department for construction requirements in your area.
The larger the deck the larger the joists. The floor joist spacing is the distance between the centers of any two installed joists. 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. What size should floor joists be.
