I'm looking to construct a 17'x25' (approx. 375 sq/ft) ground level deck and was curious to find out if the same rule for 48" deep footings would be required or If I could get away with using a Deck Block dug into the ground?
You actually dont need to put footings. you can install screw piles. there is a company that I work with and its called. Techno Metal Post Vancouver. They supply and install screw piles. you can get a few screw piles installed and then build your deck above the piles.
So yes, the previous contractor was correct with his answer you dont need the footings to do a deck that is ground level however you will need to have it safely secured before building so you wont have future problems with the deck.
I'm with everyone else, deck blocks are fine! Mike touched on a very important part. Make sure you prepare the base properly and create some drainage. That will make for a more stable base that shouldn't move too much.
Good luck with it.
It sounds like a relatively simple deck and I am assuming that you plan to build it yourself. Not an issue but be aware of the time it takes and all the prep work that should be done. The ground, if undisturbed soil, if fine to use blocks. If it has been excavated and refilled, it will require tamping and a good base (gravel & sand). To be sure about the proceedure in your area, you should call a building inspector (information is free) or ypur local town /county office. Every county may be different in their inturpretation of the safety codes. Enjoy your deck.
As it is ground level you may be able to get away with blocks. However that being said my brain alarm goes off. Out here in Alberta we have a high water table which means a deep frost level. I always go by the town/city regs. Most out here want 10" x 10' deep piles. Done municipalities will let you get away with screw piles but the end choice is yours. I believe it's a question of safety personally. I wouldn't want a serious injury or death on my conscious.
Yes you can use the deck blocks as footing but the deck would be more sturdy if you sink the posts in the ground 48". if the deck is being constructed on the ground level it is classified as a floating deck and you can use the deck blocks. However with the deck blocks the deck will shift with the ground.If you sink the post in the ground 48" it will keep your deck from shifting.the 48" footings are generally used if the deck is constructed at a higher elevation and the post are attached with a post shoe sunk into the concrete.
Good luck with your project.
To answer your question, the answer is YES you can use deck blocks for your foundation...however, the deck MUST NOT be attached to the house or any other structure and must be 1' 11" or less off the ground, and under 55 square metres (592 sq.ft.) which yours is.
It also MUST NOT support a roof (i.e. Pergola, Arbor, Shed, Gazebo, etc.)
It is good practice to remove at least 8" of soil and replace it with a gravel base that will permit the drainage of ground water and can be levelled prior to placing the deck blocks.
Uplift is also a concern for these types of decks and while it may not be a major concern in the Toronto area it is cheap insurance to install 2 screw piles with anchoring straps to the framing to prevent damage to your deck, neighbouring structures, or people in the case of high winds.
Next, and this is extremely important, you MUST ensure that the pressure treated lumber you use is rated as "GROUND CONTACT". Often the pressure treated lumber from the box stores is NOT with the exception of posts.
This is extremely important on ground level decks as the framing will rot out very quickly. While most box stores will order it for you, you might have better luck at local building centres out your way. The lumber must be tagged or stamped as "UC4" under CSA regulations. Most pressure treated framing lumber is "UC3" and is NOT rated for ground contact.
Lastly, if the pressure treated lumber you use is "ACQ" or "CA", which most is since 2004, the treatment uses a higher amount of copper and will corrode galvanized fasteners and hardware very quickly, to the point of failure.
While most suppliers now carry the nails, screws, hangers, etc. that are rated for the newer treated lumber, take a second and make sure the item, be it joist hangers or nails, are rated for ACQ or CA treated lumber.
Best of luck with your project.
Cedarfalls Building Consultants Limited
Thanks Everyone! Super helpful information!!!
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