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Hi All.
New homeowner here with little experience. I have a contractor framing out a deck for me. Its a basic 16 x 18 shape and the elevation at the house is only about 12''.
The footers are laid out in a 3 x 3 grid, 8'' in diameter. The space between each footer is about 7'. Due to low elevation, he is not using posts. Instead, he brought the concrete out level and is running 4 x 4 PT beams over top of each footing. The beams are tied in with a bracket. He is using 2 x 8'' floor joists with hangers on the ledger board.
From a support perspective, are 4 x 4s enough to support this size deck? Given the elevation he could not use 6 x 6s, but should he have used 4 x 6s?
Thanks.
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4x4's are not meant to be used as beams, they will sag. Even 2-2x4's with p.t. plywood sandwiched and glued between is better, but if you can fit 2x6's with plywood it would be much better. Jason
JR Freed
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Thanks. I was thinking of either having add two additional rows of footers to make the distance between each around 3' or user 4 X 6s instead....or both.
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Well, I have since fired the contractor. The township put a stop work order on the deck job. The contractor was stating that it did not need a permit since it was technicall free floating and not structurally supported by the house. The contractor was doing other work on my house as well and after 6 weeks of excuses, I decided it was time to move on.
The township inspector said that the span between footers is too long for 4 X 4s. Code for the township is min 2-2X8s for 7' spans. So it looks like I need to put additional footers in or replace the materials since I am so close to the ground.
The contractor used 2X8 floor joists and 4X4 beams which only gives me about 1 1/2" clearance from the deck board to the door jam. So if the township works with me and says I can use 2-2X6s instead of 2X8s then I could drop the floor joists down to to 2X6s and still have room. If they hold firm to their requirements then I will have put new footers to decrease the span to 3 - 3 1/2'.
Needless to say, I am anxiously waiting to hear back from the township. So far, they seem very willing to work with me.
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The engineer from the township said I will need to make some adjustments to reduce the span between footers. I could put additional footers in, but I would need to rip the framing down to do it. Another option is to slide concrete blocks under the beams and make the difference up with a post. I only have about 3 inches clearance from grade to beam. They do not have a minimum depth or even min length/width.
Home Depot has 4 X 8 X 16 heavy weight concrete block. I was probably going to go that route, but I am open to any suggestions.
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I know this may not be the option you want to hear but if it were mine, I would take the deck down entirely and start over.
You have a couple of options on design. A 2x10 will span 16' @12" o.c. so you can use 2x10's for floor joists and double the outer rim joists. Notch and attach 6x6 support posts to the outer rim joist and it becomes the support beam or sit the doubled outer rim joist directly on a concrete support footing.
second option is to again use doubled 2x10 rim joists for your support beams but frame in an additional doubled 2x10 across the center of the deck and support with footings. This will become a center support beam. You can then use 2x8 floor joists 16" o.c. to span from house ledger to center support and from center support to outside rim joist.
if you have 12" clearance from grade to threshold, the 2x10 is actually 9 1/4" and a deck board is 1" which gives you 10 1/4" leaving 1 3/4" to threshold which is plenty.
another thing. this deck in my county would be considered a free floating patio if it were built on grade level. Code states any platform 10 1/4" or less to grade isn't load bearing and doesnt require a permit.
Les
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| Thanks for the advice. Turns out, the contractor went only 24" in depth on the footers. The township requires min depth to be 36". Looks like I will be rebuilding.
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