Deck Footing Depth

August 20, 2019

Total height of low level ground level deck. We prefer to use a footing to stabilize the deck from settlement and use a pier with rebar to get the post connection above grade.

Deck Footing Depth Frost Line Map Decks Com Decks Com By Trex

With these style of deck footings there is a.

Deck footing depth. This is a common rule for footing so dont forget that. Regardless of reaching solid ground before a minimum depth of 600mm the deck footing should be at 600mm deep always dig bigger never smaller. The Prescriptive Residential Wood Deck Construction Guide by the American Wood Council AWC link at the bottom of the page contains a table that explains the sizes of footings based on Beam Span Joist Span and Live and Dead loads.

Footing Installation Deck Footing Size Chart. This is called the tributary load. In frigid Minnesota the frost depth is 42 in whereas a warmer state like Missouri may have a frost depth of only 1 ft.

The frost depth varies by region. If you multiply the area of this section 5 x 5 you will get 25 square feet. Footings should extend to a minimum depth of 12 inches below previously undisturbed soil.

In a cold climate you must check local regulations to ensure that your deck footings are placed below the frost line. Look at our US. As you see the closer the footings spacing the smaller of beam you can use.

You can multiply this area by 55 lbs per square foot. Uncut end embed in concrete to the footing at 24 deep due to the height restriction for the framing. I am building a 10x12deck not attached to a ledger board.

I did a large deck on clay and dough down 700mm and poured a pad 750x750x200 deep. Learn how large to make your deck footings. Using our 10x10 deck example the footing size is 16x16 406 x 406 mm with a depth of 7 178 mm.

The footing sizes also depend on the load-bearing capacity of the soil and the live load the deck must support. Find out how deep you need to dig your footings in your area. A smaller deck with footings between 6 18m and 8 24m a single 26 beam can support joist less than 7 213m deep.

All supports shall be restrained from lateral displacement at the footing. Footings need to be at least 12 inches below settled soil to prevent lateral movement. Sizing Deck Footings Assuming a minimum soil bearing capacity of 1500 psf 8-inch-diameter concrete piers bearing on square footings measuring 2 feet on a side and 9 to 11 inches thick are adequate for most single-story decks where beams are spaced 14 feet apart or less and joist spans are 14 feet or less see table below.

If your engineer has specified a minimum depth you need to dig to that depth. Footings also must extend at least 12 inches below the frost line the depth to which the ground freezes in winter or must be frost-protected. My plan was to pour concrete footings then run doubled up 2x8 beams setting on the footings.

You only have to. Ill bet you didnt know that the IRC doesnt always require deck or shed footings to be below frost depth. A new table in the 2018 version of the IRC Table R5073 specifies footing size as it related to soil composition and live load.

It does require this when a deck is attached to a house but if youre building a shed or a freestanding deck you dont need frost footings. Height of Deck Against Door Threshold. We typically use a 8 dia x 8 thick footing with 4x4 PT.

Reducing the footings spacing to 4 12m will support all depth of a deck up to 15 46m. Its the only way to avoid frost heaving. Apr 28 20 1117 AM.

The remaining half of the deck will again be split into two parts to be supported by the two corner footings. I then built a 450x450 pier out of 100mm dence conc blocks laid flat to just below ground level and then set large stones onto it to suit the building. Sep 04 19 1112 AM.

Use our table for maximum allowable loads to determine the proper size for your soil type. Building codes cover most of the basics about footing size frost depth and the bearing capacity of soil and concreteCodes dont however tell how to dig a proper footing hole. Footing Installation Deck Footing Frost Depth Map.

A good hole is smooth straight and flat-bottomed. START WITH A GOOD HOLE. You will notice that the support post is also embedded deeply into the concrete and extends no closer than say 4 from the bottom of the footing.

In the coldest northern states you may need to dig and place your deck footings as deep as 48 below grade. The flat part at the bottom must be at least 6 thick. Depth wise you should go at least below the level of topsoil depper still to avoid frost heave in the clay soil.

DECK SUPPORT POSTS All deck support posts shall be a minimum 6x6 with a maximum unsupported height of 10-0 measured from the top of the footings to the underside of the beam. When you contact your local building department to get your building permit ask what the frost depth requirement is and the required size and shape of the footings. Map of extreme frost penetration.

The Basics Of Deck Footings Fine Homebuilding