Post set in concrete
Even if you're setting deck posts in the ground,instead of on top of footings, the concrete still needs toextend below the frost line.Thus, a 3,600-pound cubic yard contains about 800pounds of cement, which comes out to 10 of the 80-pound bagsof cement or 13.3 of the 60-pound bags.
Set the post into the hole and attach 2x4braces to adjacent sides of the post. Use a level toposition the post perfectly vertical. Fill the hole withFast-Setting Concrete up to 3 to 4 inches below groundlevel. Pour about a gallon of water per 50 lb bag into the hole andallow the water to saturate the concrete mix.
If you use a concrete that has a quick settingadditive you need to wait a minimum of one sunny day, if you areusing a standard concrete footing mix I would recommendwaiting for a minimum of seven days and a maximum of 28 days, ofcourse, that is if the conditions are right for the concreteto cure and set hard .
Estimating 60-lb Bags of Fast-Setting Concrete Mix
| 3-in Post Diameter / 9-in Hole Diameter | 6-in Post Diameter / 18-in Hole Diameter |
|---|
| Hole Depth in Inches | Number of Bags needed Per Hole | Number of Bags needed Per Hole |
| 10 | 1 | 3 |
| 12 | 1 | 4 |
| 14 | 1 | 4 |
Concrete for a poured deck footing usually costs$50 to $100 per footing, depending on the diameter, depth,and size of the base.
Although concrete will harden soon afterpouring, it's still susceptible to damage from weightduring the first four weeks. Wait at least 24 hours beforeallowing foot traffic, including pets, on a newly poured sidewalkor slab, and don't drive a vehicle on a new driveway for at least10 days.
Q&A: Rebar in Sonotubes. A larger-diameterpier should have four or more pieces of verticalrebar. The rebar provides the tensile strength neededto resist lateral stresses that can be applied to a concrete pierby ground movement, freeze cycles, and wind loads.
In areas with freezing winters, a concretefooting usually must extend at least 12 inches below the frost line(the depth at which soil freezes). A footing should also beat minimum 8 inches thick and twice as wide as the wall or posts itwill support.
Depth: Footings should extend to a minimum depthof 12 inches below previously undisturbed soil. Footingsalso must extend at least 12 inches below the frost line(the depth to which the ground freezes in winter) or must befrost-protected. Width: Footings should have aminimum width of 12 inches.
Time. No single answer exists for how long adeck footing needs cure before building the deck ontop of it. The Portland Cement Association advises thatconventional concrete cures for five to seven days for bestresults. Some manufacturers make rapid-curing concrete for deckfootings that cure in 24 hours.
Building an 8-by-10-Foot FloatingDeck
Floating decks are so called because, ratherthan being attached to a building as are standard decks,they simply "float" on top of the ground. Floatingdecks can be set directly on the ground or, preferably, a bedof gravel. But it's best to support the deck on concreteblocks.Generally, one stick of rebar per 8 inches offooting width will suffice. If your footingsare 16 inches wide, you will need to add two sticks ofrebar along the width of the footing; however, ifyour footings are 24 inches wide, you will need threesticks.
- Lay down a layer of channel blocks around the footing'sfoundation.
- Insert the vertical rebar directly in the middle of the channelblock.
- Cross two, 1-by-3-by-8-foot wood strips to form legs on thevertical rebar.
- Pour concrete into the channel blocks.
- Remove the wood strips.
Rebar is recommended for concrete thatmeasures 5-6 inches in depth. The type of and intended use ofconcrete impacts the need for rebarreinforcement. Rebar must be placed at the center of orslightly above the center of the concrete slab—hencewhy it should be a certain thickness for bestresults.
Thankfully for most porch designs, planningpermission isn't required. If you live in a house, thework is considered permitted development, providing that: Theground floor area does not exceed three square metres,measured externally.
Building Regulations. Building aporch at ground level and under 30 square metres in floorarea is normally exempt from the need for buildingregulation approval. For a porch to be exempt frombuilding regulations approval: the front entrance doorbetween the existing house and the new porch must remain inplace.
Adding a porch to any external door of your houseis considered to be permitted development, not requiring anapplication for planning permission, provided: the groundfloor area (measured externally) would not exceed threesquare metres.
The IRC requires frost footings to be installedfor all decks that are attached to a house in most climatezones. These footings will have to be inspected to make surethey are capable of supporting your deck and will resistdamage from frost.
How to Calculate Footing Size
- Determine the width and length of the cement slab ininches.
- Divide the width by 12 to convert it to feet.
- Divide the length by 12 to convert it to feet.
- Determine the depth or thickness that is required for thefooting in inches.
- Multiply the width by the length and then by the depth.
3 Answers from MyBuilder ConservatoryInstallers
You need to dig footings at least 900mmdeep and 500mm wide.It varies based on the style or your porch andthe materials, but on average, porches cost between$15,000 and $30,400. How much does it cost to build afarmer's porch?
3 Answers. You need to place the footings deeperthan the frost line. Some research says the frostline in CT is around 42" so you'd do well to put the posts down48". The city will be able to verify this when you get your permitapproved.
That's why there are minimum foundation depthsfor each type of clay. Strip, trench fill or pad foundationsmust be cast at a minimum of 750mm in low plasticity clays, 900mmin medium, and 1000mm in the highest risk areas.
