The Joists on a Beam calculator
computes the number of joists (joists and end plates) required for a floor or deck based on the dimension of the room or deck and the on-center joist separation and length of joists being employed. It also indicates the number of beams required to have an overlap of joists above the beams.
INSTRUCTIONS: Choose units and enter the following:
- (W) Width of Floor (across joists)
- (L) Length or Span of Floor (parallel to joists)
- (oC) On-center Separation distance between joists
- (JL) Joist Length
- (JO) Joist Overlap (default: 10")
- (PB) Plate Board Length
Floor Joists on Beams Board Count (JC): The calculator returns the number of joists and end plates, their lengths, the number of beams, their lengths and their spacing to be centered. The calculator also returns the number of joist hangers (ties) needed.
- (nJR) Number of Joist Rows
- (nBM) Number of Beams needed
- (BSpac) Beam Spacing
- (TJB) Total Number of Joist Boards
- (nJH) Number of Joist Hangers needed
- (nP) Number of Plate boards for Perimeter
The Math / Science
The Joists on Beams calculator ...
- computes the number of rows of joist along the floor / deck width,
- computes the number of beams, if any, that are required, to match the span of the length based on the length of joists specified,
- computes the number of joist hangers needed, and
- computes the number of plate boards to completely belt the floor / deck. This includes plate board that run along beside the first and last joist and the plates that meet the start and end of each joist.
Menards carries I-joists up to 40' as of this writing . It takes the width and calculates the number of joists needed to meet the on-center spacing requirement, and includes one for the beginning and an extra for any partial space. The algorithm then calculates the number of end pieces (plates) needed based on the width and the joist lengths.
It is important to note, that the strength of the joist and its length are driven by the use of the floor. A free standing outside deck for some light furniture and a few people will have a different load requirement than a deck for a hot tub. For this reason, this calculator does not tell you what boards or I-joists to be used, just how many. The most common driving factor in joist selection is the Live Load which is the specification for the load (weight) that is placed on a square foot of the floor. Local building codes also dictate what joist boards can be used. The live load will most commonly drive the Maximum Joist Span.
AS ALWAYS, CONFORM TO LOCAL BUILIDING CODES AND CONSULT PROFESSIONAL ENGINERING SPECIFICATIONS FOR ALL CONSTRUCTION AND DO NOT RELY SOLELY ON THESE CALCULATIONS. CONFIRM THEM WITH AUTHORITATIVE SOURCES!
Deck Builder Calculator provides estimates for a simple rectangular deck project. Calculator functions include the following:
- Deck Board Count: Computes the number of decking boards needed for your deck based on the size of the deck and the size of the decking boards.
- Deck Boards Cost: Computes the cost of deck board flooring based on a computed number of deck boards and the price per board.
- Decking Cost Estimate: Estimates the cost of wood board decking based on total area and unit pricing in dollars per square feet.
- Subfloor 4x8 Sheets: Computes the number of 4x8 sheets to cover floor/deck area.
- Subfloor Cost: Computes the cost of 4x8 sheets to cover fool/deck area.
- Deck Joist Count: Computes the number of floor joists needed for a deck. It returns the number of joists and plate boards, square feet of area and the length of the diagonal.
- Joists on Beams
: Computes the number of joists (2x dimensional lumber or i-joists), number of beams, number of joist hangers, and length of plate boards needed for a floor or deck with a span that might require one or more beams. - Deck Joist Cost: Computes the total cost of the floor joist boards.
- Deck Stain and Sealer: Computes the amount of stain and sealer needed for a deck.
Joist Calculators
- Floor Joist Count:
Computes the number of joists (joists and end plates) and joist ties required for a floor or deck based on the dimension of the room or deck and the on-center joist separation. - Floor Joist Cost: Estimates the cost of Floor Joist boards (joists and end plates) required for a floor or deck based on the dimensions of the deck, spacing of joists and unit cost of joist boards.
- Joist Hanger Count:
Computes the number of joist hangers required for a deck based on the width of the deck and the spacing of joists. - I-Joist Count: Computes the the number of I-Joist boards required to cover a span (width) based on the size of the span and spacing of the I-Joists.
- Maximum Joist Span: Computes the span length of a (1,200 pounds per square inch fiber stress) wood joist based on the live load, spacing, board width (e.g., 2x6 vs 2x10) and whether the joist need to be extra stiff for materials attached such as plaster below them.
- Joists on Beams:
Computes the number of joists (2x dimensional lumber or i-joists), number of beams, number of joist hangers, and length of plate boards needed for a floor or deck with a span that might require one or more beams. - On Center Spacing: Computes the even spacing between a number of objects (e.g. posts, studs, joists, rafters, trusses, lights, rebars) over a specified length or distance.
