Deck Footing Size Calculator
Post Spacing =
Roof Overhang =
Dead Load = 10
Live Load = 40
Snow Load = 0
Soil Capacity = 1500
Deck Area =
Roof Area =
Calculates the size of footings required for a covered deck with one side supported by a structure. This is based on the number of footings and posts supporting the deck, and the tributary area supported by each footing and post. It assumes a soil-bearing capacity of 1500 psf, the default capacity assumed in the 2009 IRC.
-Span: Total span of the deck from where it rests on the ledger to its outside edge.
-Cantilever: Length of the cantilever beyond the post (if any).
-Post Spacing: On-center spacing of posts.
-Roof Overhang: Length of the overhang beyond the end of the deck.
-Dead Load: Weight / loads considered to act permanently; they are "dead," stationary, and not able to be removed.
-Live Load: Weight / loads produced by the use of the deck. Does not include elements such as snow.
-Snow Load: Probable amount of snow that will rest on the deck based on your geographical area.
-Soil Capacity: Bearing capacity of the soil. 2009 International Residential Code establishes the assumed bearing capacity is 1500 psf.
-Deck Area: Area of deck to be supported by one footing and post.
-Roof Area: Area of roof to be supported by one footing and post.
-Deck: Total weight per square foot of the DECK to be supported by one footing and post.
-Roof: Total weight per square foot of the ROOF to be supported by one footing and post.
-Total: Total weight per square foot of the DECK and ROOF (combined) to be supported by one footing and post.
-Dimension: Length and width of the square footing.
- Thickness: Depth of the footing.
-Diameter: Diameter of the round column.
-Depth: Depth of the footing.
Determine the footing size for a deck that measures 20 feet parallel to the house and is 14 feet deep. There is to be a 1 foot cantilever beyond the beam, which is 20 feet long. The posts are spaced 6 feet 8 inches apart. The deck is to be roofed with 1ft overhang, and each post and footing will share the combined loads of both the deck and the roof. The deck live load is 40 psf, and the design snow load is 30 psf.
-Post Spacing: 6ft 8in
-Roof Overhang: 1ft
-Dead Load: 10 psf
-Live Load: 40 psf
-Snow Load: 30 psf
-Soil Capacity: 1500 psf
The following results are calculated:
-Deck Area: 50.00ft²
-Roof Area: 56.67ft²
-Dimension: 1ft 9&3/8in
-Diameter 2ft 1/8in
-Depth: 1ft 1/16in