I NEED HELP WITH A CONSTRUCTION QUESTION ABOUT POSTS FOR MY DECK

Typical heated slab is for snow melt driveway would be dug out to allow for material thickness. Then a layer of stone for drainage, vapor barrier plastic sheeting, then foam board insulation, then 4" slab over foam to finish height. In your case the foam board would insulate the ground, significantly reducing the frost depth of the area under the insulated area. You can extend the insulation past the slab and burry with dirt out say 36" beyond the outer posts. When finished it a concrete slab with lawn coming up to the edge of the concrete.
Here is an illustration of the rough principal applied to your situation. Disregard everything other than the slab construction in this illustration:
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Thanks Red, very interesting. I appreciate your thoughts and wisdom on this. Sincerely Thank You. 👊🏻👊🏻👊🏻🙏🙏🙏😉
 
From the looks of you pictures, it appears that your beams attach to your posts with just nails? If this is the case, I highly recommend that you view this video (starts around the 3:00 minute mark) to help shore up the beam to post connection and make it stronger:

I'm not an engineer or deck expert; I'm just offering my opinion to help your deck be as safe as possible. With the size of your deck and potential load, trusting a few nails to hold all that weight could be dangerous.
 
From the looks of you pictures, it appears that your beams attach to your posts with just nails? If this is the case, I highly recommend that you view this video (starts around the 3:00 minute mark) to help shore up the beam to post connection and make it stronger:

I'm not an engineer or deck expert; I'm just offering my opinion to help your deck be as safe as possible. With the size of your deck and potential load, trusting a few nails to hold all that weight could be dangerous.
We drilled lag bolts into each post that was sandwiched between 4x8x16" plank to make up the header. I also have 8 x 5/8" bolts to drill through it also. Now I'm removing the wooden posts and installing Steel Lifting Shores / Lifting Jack Posts that are going to be sitting on cement piers that will be 36" under ground with rebar. Its costing me an arm and a leg to do this. 12 piers at 300$ a pier so thats 3,600$. The jack posts and clips are another 4500$. Then to level the ground and cut the stoop another 3,500$. Then to make 8x8' sections of concrete to cover 38'x16' is 9,500$. So damn expensive. about 18K$.
I almost said screw it and I was going to wait. But my father died in March and I now see life being so fragile and short, I decided to make it happen and enjoy my life and my home to it's fullest. You don't know what can happen tomorrow or a year from now.
I'm just a straight up dude, that gives all the details. IDK. Praise Be To GOD That I Am Able To Get This Done On The Spur Of The Moment. 👊 👊 👊 🙏🙏🙏✌️✌️✌️
Donny Details;)
 
Well today they removed 2/3 of the dirt to level it out to have west a as 76” height once the concrete is poured to bottom of floor joist.
This phase is only for the concrete pour. It’s still needing to be dug out for another 17’ gor pavers with a concrete slab under the pavers to prevent ants and to be hard core.
It’s a very expensive project BUT it’s going to be awesome. I had money put aside for a RV but that is now put on hold dropping major money on this deck and now the patio under the deck. 👊🏻👊🏻👊🏻🙏🙏🙏😉
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I need a bit of help with the damn posts again. Everything is getting ripped out and 40” deep pilings 12” wide are going in the ground. I bought leveling posts that hold 8,000lbs.
I was going with 1 in the center. 2 on the ends and 1 in between the end and the middle. But that’s a span of 7’.
I originally had 6 posts per that header. Will this be ok. Should I order another post per header and have 2 more footings or pilings made.
Thanks. It’s been spinning out of control with expenses. It’s costing me a fortune. Not being able to get the RV this winter.
We are also now siding the back of the house and sides and a new sliding glass door.
Donny Details 👊🏻👊🏻👊🏻🙏🙏🙏😉

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I need a bit of help with the damn posts again. Everything is getting ripped out and 40” deep pilings 12” wide are going in the ground. I bought leveling posts that hold 8,000lbs.
I was going with 1 in the center. 2 on the ends and 1 in between the end and the middle. But that’s a span of 7’.
I originally had 6 posts per that header. Will this be ok. Should I order another post per header and have 2 more footings or pilings made.
Thanks. It’s been spinning out of control with expenses. It’s costing me a fortune. Not being able to get the RV this winter.
We are also now siding the back of the house and sides and a new sliding glass door.
Donny Details 👊🏻👊🏻👊🏻🙏🙏🙏😉

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I just ordered 2 more setups. So 6 per header.
 
I need a bit of help with the damn posts again. Everything is getting ripped out and 40” deep pilings 12” wide are going in the ground. I bought leveling posts that hold 8,000lbs.
I was going with 1 in the center. 2 on the ends and 1 in between the end and the middle. But that’s a span of 7’.
I originally had 6 posts per that header. Will this be ok. Should I order another post per header and have 2 more footings or pilings made.
Thanks. It’s been spinning out of control with expenses. It’s costing me a fortune. Not being able to get the RV this winter.
We are also now siding the back of the house and sides and a new sliding glass door.
Donny Details 👊🏻👊🏻👊🏻🙏🙏🙏😉

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It's hard to be sure we understand your plan based on photos and pics. If it were me, I'd put one post on each end and one in the middle if, based on what you've said, that would result in spans of about 14'. The header can be upgraded much more cheaply and easily than adding posts. Just sandwich more 2 X 12's to it.
 
It's hard to be sure we understand your plan based on photos and pics. If it were me, I'd put one post on each end and one in the middle if, based on what you've said, that would result in spans of about 14'. The header can be upgraded much more cheaply and easily than adding posts. Just sandwich more 2 X 12's to it.
I’m putting 6 posts per header. 12 total. I wanted to eliminate 1 post and go 5. The header is 2x8x16. Then another 2x8x16 to make the one header 32’ long. 6 posts about 6’ apart from each other. So I’m going to put steel leveling posts next to the 6 wood posts then eliminate the wood.

if I went just 3 that would be a span of maybe 14-16’ apart.
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I’m putting 6 posts per header. 12 total. I wanted to eliminate 1 post and go 5. The header is 2x8x16. Then another 2x8x16 to make the one header 32’ long. 6 posts about 6’ apart from each other. So I’m going to put steel leveling posts next to the 6 wood posts then eliminate the wood.

if I went just 3 that would be a span of maybe 14-16’ apart. View attachment 33885View attachment 33886View attachment 33887
Upgrading the header is much cheaper than those steel posts.
 
He needs to go down to a depth deeper than the existing posts are due to the excavation for a new patio so he's doing steel posts and deeper concrete footings. An upgraded header won't solve that issue.
If the header was upgraded he could use fewer posts. There's no reason they can't be cheap wooden posts.
 
It may not sound great, but why don't you add a few more temporary posts and stagger then between your permenant ones (on concrete post blocks). Get a couple of bottle jacks and then you can knock out the ones that are set at incorrect depth and reinstall them after digging out the old footing.

Have you had the local muni check em out too?

If you're doing concrete slab below your deck, my recommendation is to remove the posts at incorrect depth and pour a concrete pier in its place that comes up above your finished grade and set a post on top of it via Simpson ties. Then your buddy can dig around them, install isolation membrane like sillguard, and then pour your new slab around your piers and they will remain independent structures. I'd advise against direct burial of posts and pouring concrete around them like that. They will be impossible to replace and will rot out in no time.

Edit* another alternative is to look at Diamond Piers, they are installed above grade similar to concrete blocks but you'll have to contact them regarding the slab pour - not sure they'll guarantee their product in that application.
I'm aligned with your thoughts. My deck is totally independent from the house since that is now code with a brick exterior. I had a pad poured underneath that is totally independent from the deck, isolated from the posts. We dug out about 6" so that I would end up with 7' height underneath, but that was known from the beginning. I would not want to excavate after the fact without replacing the posts.
 
If the header was upgraded he could use fewer posts. There's no reason they can't be cheap wooden posts.
You still need a certain number of posts to support the structure and accommodate the dead/live loads. Regardless of header size, each deck requires a certain number of posts based on size, cantilever vs. attached, and weight of materials to accommodate a typical 50psf rating. Your rationale works with framing for replacement of load bearing walls and doorways but not outside. The only way he can get away with using less posts, is by expanding his footing sizes and posts to 6x6.

Remember, these posts are there to spread the load of the deck across expansive soils not inside of a house on a foundation.

Here's an article that explains what I summarized in greater detail:

 
I'm assuming the posts would be on concrete - he's pouring footings and a pad - attached (and gapped off the concrete to eliminate moisture wicking) with appropriately engineered ties. If it were my patio, I'd want fewer posts. Yes, the posts should be sized for the loads. Ostensibly, and if it's attached appropriately, the rim joist attached to the house will carry some of the load to the house footing. I'm just pointing out that by adding material to the header, he can span farther between posts. It would also be much cheaper if he sticks with the steel jacks, as he'll require fewer of them, and they're more expensive than wood. As is, it's a forest of posts. I'd want fewer posts to make the patio more useable.
 
I'm assuming the posts would be on concrete - he's pouring footings and a pad - attached (and gapped off the concrete to eliminate moisture wicking) with appropriately engineered ties. If it were my patio, I'd want fewer posts. Yes, the posts should be sized for the loads. Ostensibly, and if it's attached appropriately, the rim joist attached to the house will carry some of the load to the house footing. I'm just pointing out that by adding material to the header, he can span farther between posts. It would also be much cheaper if he sticks with the steel jacks, as he'll require fewer of them, and they're more expensive than wood. As is, it's a forest of posts. I'd want fewer posts to make the patio more useable.
The only way he can span further between posts regardless of header size (height or thickness) is if he has the appropriate size posts and much larger footers (e.g. 18"-24") than the 8-10" sonotubes I see in the pictures. Again, your original comment that stated upgrading the header size to use less posts is incorrect. Post spacing and count is based on deck size, soil composition, and anticipated load - the sizing of the structural beams they support do not dictate the post count.

If he wants less posts spaced out further, then yes the deck needs to be constucted using larger beams but in addition, he will need much larger footers and posts.
 
The only way he can span further between posts regardless of header size (height or thickness) is if he has the appropriate size posts and much larger footers (e.g. 18"-24") than the 8-10" sonotubes I see in the pictures. Again, your original comment that stated upgrading the header size to use less posts is incorrect. Post spacing and count is based on deck size, soil composition, and anticipated load - the sizing of the structural beams they support do not dictate the post count.
Nonsense. Are you saying, given the right soil conditions, that header would support the entire deck on one post?

Why are headers ever different sizes? It's because you can span farther with a bigger header. Bigger header equals longer header equals fewer posts.
 
Nonsense. Are you saying, given the right soil conditions, that header would support the entire deck on one post?

Why are headers ever different sizes? It's because you can span farther with a bigger header. Bigger header equals longer header equals fewer posts.
That's not what I said, it's what you said in your original comment about reducing post count by reinforcing the header. I said the only way you can reduce post count is by also increasing the size of the footers and posts and not by simply increasing the header size as you suggested.

Here you go bub, use a calculator. You'll see that by increasing the deck size and post spacing, both beam and footing sizes will change - not one or the other.

https://www.decks.com/calculators/beams-and-footings-calculator
 

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