I'm building a small elevated deck off the FROG. It's 10'x10' framed from 2"x10" lumber. The area below the deck is a paverstone patio. I removed pavers from two areas to pour footings to support the outer edge of the deck in a cantilever design. These footings (each filled with 160lbs of concrete) are 12" round and 20" into the ground. Wooden forms were built to create 6"x6"x3" risers (poured with the 'below ground' footer) to fit into the paver pattern in lieu of one 6"x6"x3" paver. My intention is to drill a single hole into the center of each riser about 8" deep and install 5/8 epoxied threaded studs. A 5"x5"x.5" plate will be center drilled to slip over the stud. A 3.5" OD pipe of .120" wall will be 'mouse hole' notched to allow access to the stud, centered over the plate and welded together. A a 10' long W6-13 I-beam will be sat on top of the 2 pipes and all welded together to support the deck framing. The I-beam will be drilled to fit timberlock screws through the upper flange and into each deck joist tying it all together. I don't want to use 6"x6" timbers as this is next to the driveway and might possibly get bumped. If you're having trouble invisioning this just imagine a fixed gantry supporting the outer edge of a desk. I'm I over thinking this?
Opinions on elevated deck support
- Thread starter ezzzzzzz
- Start date
Is a FN understatement...gezzis man that thing will outlast three life times worth of decking material. Ya know you would have been fine with a embedded post support and 4X4 riser mounted inwards from the outer edge 1ft and 4X8 support.
In my book over kill kicks ***, so what you've done rocks.
RickP
Well-known member
Wow - your design sounds BEEFY...
I like your idea of steel posts rather than wood in case they get bumped in the driveway. I'd prolly use wood myself, but the steel posts will provide extra protection.
Your design makes total sense up to the steel beam. Couldn't you use the steel posts to support a wood beam? How tall is the deck? It sounds like everything above that beam is wood anyway, so that beam could also be wood and it wouldn't hurt your design. Wood is plenty strong for that span, and protecting a steel beam against rust will be a major pain in the future.
Curmudgeon
Well-known member
You don't say where you're located, but your footings may or may not be deep enough. If you're in an area where the ground freezes in winter, make sure they are deep enough that they're below the frost line. Otherwise your deck is going to move. If you read your local building codes they will tell you what is required in your area.
If you're in Arizona, don't worry about it.
If you're in Arizona, don't worry about it.
MScott
Well-known member
x2. I am building a similar 10 x 12 deck and my footings are 4 feet into the ground. You will get much more relevant answers if you put your general location in your profile.
x3 on it may or may not be 'enough' and it may or may not be 'to Code'.
Footing size requirements depend on soil conditions AND the overall load to be supported. Footing depth requirements depend on soil conditinos AND local frost depth (footings must be installed to rest on 'undisturbed' soil and be below the local frost line.).
A W6x12 I-beam -should- be strong enough to span a 10 ft length supported on posts near the ends and holding up a 'deck' (40 lb/ft2 live load and 10 lb/ft2 dead load), but you would have to check with your local building department as to whether that meets Code requirements for your locale.
A 3.5" hollow pipe may or may not meet 'Code' requirements to act as a support post for a deck. Check your local Code requirements.
The 1/2" thick 'base plate' sounds like a nice bit of overkill, but putting a 'mousehole' to get a nut and wrench in there to attach the plate and post to the anchor stud would expose everything to water and the weather (and make a nice place for bug, wasps, and other vermin to make a home). I'd rather leave the post 'solid' and put anchor studs/bolts on the perimeter of the base plate.
Remember that 'structural welding' will need to meet "Structural Welding" codes as far as materials, procedures, filler metal, etc.
Also, since we don't know your locale, in addition to footing depth depending on frost line requirements, there may or may not be seismic construction Codes/requirements that may have to be met as well.
Also remember that exterior steel must be protected from corrosion and the 'new' PT lumber in contact with steel is -very- corrosive (both the metal framing and the fasteners must meet corrosion resistance guidelines/requirements which usually require either hot-dipped galvanized or 'equivalent' or some sort of 'equivalent' proprietary coating).
Do-able? Yes.
But you'll have to check all the specifics for your locale first.
Footing size requirements depend on soil conditions AND the overall load to be supported. Footing depth requirements depend on soil conditinos AND local frost depth (footings must be installed to rest on 'undisturbed' soil and be below the local frost line.).
A W6x12 I-beam -should- be strong enough to span a 10 ft length supported on posts near the ends and holding up a 'deck' (40 lb/ft2 live load and 10 lb/ft2 dead load), but you would have to check with your local building department as to whether that meets Code requirements for your locale.
A 3.5" hollow pipe may or may not meet 'Code' requirements to act as a support post for a deck. Check your local Code requirements.
The 1/2" thick 'base plate' sounds like a nice bit of overkill, but putting a 'mousehole' to get a nut and wrench in there to attach the plate and post to the anchor stud would expose everything to water and the weather (and make a nice place for bug, wasps, and other vermin to make a home). I'd rather leave the post 'solid' and put anchor studs/bolts on the perimeter of the base plate.
Remember that 'structural welding' will need to meet "Structural Welding" codes as far as materials, procedures, filler metal, etc.
Also, since we don't know your locale, in addition to footing depth depending on frost line requirements, there may or may not be seismic construction Codes/requirements that may have to be met as well.
Also remember that exterior steel must be protected from corrosion and the 'new' PT lumber in contact with steel is -very- corrosive (both the metal framing and the fasteners must meet corrosion resistance guidelines/requirements which usually require either hot-dipped galvanized or 'equivalent' or some sort of 'equivalent' proprietary coating).
Do-able? Yes.
But you'll have to check all the specifics for your locale first.
Located in SE Va. Foundation for the garage is 18" deep in the ground. Actual foundation is 12 deep by 18 wide. These footings are 12" round and 18" deep below the pavers. Deck is 130" to top plate or 119" to bottom of joists. Everything is anchored using galvanized hardware with the exception of the timberlok bolts which are coated. These are rated at 250lb shear load. There are 16 total in the header. Another 2 in each joist at the outer edge along with joist hangers throughout. I will be painting the I-beam and poles. The bottom plate will now be 6" x 6" with 4 holes to keep the hardware external. I prefer the I-beam over the wooden beam for longivity and stability. I haven't checked with the permit folks as this was all inclusive in a building permit for my garage and room over house addition. I've give them a call.
Big-Foot
Well-known member
I found this really cool site for deck planning and almost can't believe it's free (well there are ads)..
Http://www.decks.com
Check it out.. Lots of design help there! Great resource in my opinion!
Http://www.decks.com
Check it out.. Lots of design help there! Great resource in my opinion!
Steevo
Well-known member
Long after the house, garage and residents have perished, there will stand two steel pillars with an I-beam atop them, as a monument to over-engineering.