Ideas for raising floor in new pole barn.

[greg13]

I'm STILL in the planning stage (carnona has put brakes on it big time). Planning a 24X32x11 in a flood zone. the state has no problem with me building at grade, but to raise the whole area 24" I would need all kinds of Engineering and Flood change studies. So, my thought is to simply build at grade and raise the floor 24" with fill. The company laying out the building has concerns about the fill pushing against the poles (8' centers). My thoughts are to add a short pole 6' between the main poles 4' in the ground for extra support.

I'm thinking that if I have to pour a wall or blocks to support the fill my costs are going to skyrocket.

Have a meeting with the codes guy Saturday to discuss it, Any Ideas??

Thanks.

 

[u2slow]

I would be looking at extending the fill several feet outside the building. At that point the outward pressure on the columns/footings is moot.

Google 'perma-column'... should let you keep more of the wooden posts out of the ground.

 

[greg13]

At that point I am into the "changing the grade" part of building in a flood zone. Engineering studies and changing the flood zone.

 

[Marctrees]

What about going ahead w the extra posts as in Post#1, and then stack full rough 2x cca foundation grade against INSIDE of posts up to underside of slab elevation, then a single mud skit as usual on outside of posts, and then one board layed on side w the top side of it at underside of slab elevation... kind of like a bookcase girt right up uner the slab.

So outside most 8" perimeter of slab is canlilivered between all the posts, supported by re bar AND the bookshelf during pouring... and viewing the building when completed will show all posts on outside of astacked boards, except for highest mud girt.

This way the fill squeezes the stacked boards against all the posts instead of pushing them out w their nails.

OR,

Do all like said above except stack retaining boards OUTSIDE posts, and fasten w a shitload of GRK RSS 3/8" x 8" ? structural screws w big flat washers under heads.

Note link below photo.

Marc


http://jarvispolebarns.com/retaining_wall/jarvis_retainingwall_system.htm

 

[matt_i]

The soil pushing on the posts is one issue, what does it push on in the ~4 to 8 feet between the posts....usually that's much more flexible.....and wooden or metallic but not rated for constant ground contact....

I think if you set (drystack) concrete blocks inside with care to install a bond beam of rebar (perimeter "belts") and vertical pins then fully grouted all of the cavities you'd be a ton better off. And it would disappear more or less once the floor was poured. You'd have a concrete separating metal and wood from the earth and 3 steel belts holding the soil back.

I would take care to do a lot of interior compaction, like rent a jumping jack for a week and man that personally as the interior dirt got filled up in small lifts. Big machines that can do this efficiently out in the open would not be able to enter your building.

 

[Bretny]

Do they need to see a finished floor for final inspection?

What does the engineering cost compared to a flooded garage and raising things later?

 

[nadogail]

Show us what you build.

 

[Marctrees]

"The soil pushing on the posts is one issue, what does it push on in the ~4 to 8 feet between the posts....usually that's much more flexible.....and wooden or metallic but not rated for constant ground contact...."

Huh ?

Full dimension rough 2x8 is available in all CCA treatment levels including extreme "Saltwater"

http://www.americanpoleandtimber.com/wp-content/uploads/treated_wood_specguide-1.pdf

Posts set 4' deep,properly backfilled, spaced 4 or 5' oc. w (example) 2x8 rough retaining boards will certainly contain 2' height backfill.


Marc

 

[fourbyford]

If I were building this...

I'd pour a footing (below frost line) and a foundation wall high enough to extend a few inches above the raised floor... then stick build from there (or you could post -frame)

Personally, I'd rather spend a few extra dollars up front than have to wonder when the lumber (holding all the fill in place) will fail. If you're still the owner of the building when the lumber fails, the remedy won't be cheap or easy...

PT lumber rated for ground contact isn't inexpensive!

YMMV

...D

 

[Marctrees]

He does not want "Ground contact", he needs "Foundation grade"... two very different things.

The problem exists because most lumber dealers "best" treated is "Ground contact", so customers assume it is the best that is available..They have NO idea that much longer life is available.

This "Ground contact" thinking is why soo much treated wood is rotting apparently prematurely.

"Ground contact " gives MUCH shorter life than heavier concentrations.

I'ts like I am the poster boy for linking that info so many times.......................................

Again - http://www.americanpoleandtimber.com/wp-content/uploads/treated_wood_specguide-1.pdf

And IIRC, we paid approx 25% premium for CCA UC4b over local "Ground contact" prices.

Marc

 

[NUTTSGT]

Do you have other building location options on you property ? If not, I would spend the money now, do the foundation correct and in my opinion, it would be hauling in dirt to raise the building level completely.

How bad is this flood zone ?

 

[greg13]

OK guys, good points. First since I'm 64 If I get 20 years out of it I think I'll be happy.

As for building up the whole area, to meet full FEMA requirements I would have to build up the area over 4'. They state that I have to go 24" above flood stage. That would require a huge amount of money just for the Engineering & flood water diversion study. I figure if the state will let me build AT grade with no problem I'll just bring the floor above flood stage. Pole construction seems the easiest way to do this to me. I will still need to install automatic flood vents in it to meet requirements, but since I will be above flood stage hopefully they will never be needed, just more red tape.

I meet with the code office Saturday and hopefully he can give me some advice as well, and since he has the FINAL say on what he will allow I am kinda' brain storming here looking for some different ideas. Any way I look at it the floor needs to come up 27" to be above flood stage, it's just a question of how it gets there.

Stupid me, why didn't I think of it before!!! A FLOATING slab!!!! Thanks.

 

[matt_i]

Stupid me, why didn't I think of it before!!! A FLOATING slab!!!! Thanks.

I don't think that's your best choice unless its frost protected shallow or a trenched foundation to full depth.

A low lying area is prone to collect water which says prone to freeze heaves if you ask me. And that is not a 100% loss, it is a 200% loss on your investment because how can a person remediate that problem? Tear down existing and build it back correctly on a frost protected foundation. Not a gamble I would personally want to take......

 

[Rusty Fords]

If I were building this...

I'd pour a footing (below frost line) and a foundation wall high enough to extend a few inches above the raised floor... then stick build from there (or you could post -frame)

What he said Footer below grade to required frost line protection foundation wall on top with re-bar through and re-bar comes out the top of Foundation wall bend 90 degrees in word and pour a slab on top with re-bar tying everything together.

I don't think that's your best choice unless its frost protected shallow or a trenched foundation to full depth.

A low lying area is prone to collect water which says prone to freeze heaves if you ask me. And that is not a 100% loss, it is a 200% loss on your investment because how can a person remediate that problem? Tear down existing and build it back correctly on a frost protected foundation. Not a gamble I would personally want to take......

I don't know where he is at but where I'm at in Oregon its only 12" below grade easy dig depending on soil. and of course back fill after concrete is poured.

Do it once and do it right. Good luck

 

[Firebrick43]

You will not contain the fill unless do concrete or grouted cinder block or steel pilings

I have a neighbor whom tried what marktrees suggested in his Kentucky garage built on a slope and about 12” of fill, it pushed it out.

 

[Marctrees]

"I have a neighbor whom tried what marktrees suggested in his Kentucky garage built on a slope and about 12” of fill, it pushed it out."

That very well could be, but I'm pretty sure there's a "rest of the story"

Marc

 

[Firebrick43]

"I have a neighbor whom tried what marktrees suggested in his Kentucky garage built on a slope and about 12” of fill, it pushed it out."

That very well could be, but I'm pretty sure there's a "rest of the story"

Marc

No, not really.

Boards on the outside of the post pulled the screws. They dug along the inside and installed new 2x6 and even some treated 2x4 stakes in between the post. A year later the boards were bowed out severely again. 2x material especially after being soaked and having heavy expansive soil against it is not going to hold up.

Hell I have seen to many cinder block walls pushed in to by soil. That’s why they either need rebar and grout or surface bonding cement and bond beams.

 

[Marctrees]

How big were the screws ?

My choice would be on inside of posts as I said, even if huge structural screws.

What was post c-c ? I'm talking 3.5 - 4.5 ft c-c as in thread above.

So w posts that close, and w my suggested full rough 2x lumber, holding up 2' height, you would not trust that even outside of posts w " fasten w a shitload of GRK RSS 3/8" x 8" ? structural screws w big flat washers under heads." let alone in the preferable inside the posts ?

Marc

 

[Marctrees]

Summation of my last rambling - How far apart were the posts ?

Marc

 

[greg13]

OK, so this idea has been used with mixed results. That is what I was looking for. If I did it I would go inside the 6x posts probably with 2x to retain the fill although I did consider using 2'x2' precast blocks to hold the fill. A guy had a bunch of 8' for $40 ea. Just a pain to transport and place them at 4000 lb each.

It's starting to look like a block & stick built project.

 

[41plym]

I drilled though the posts and ran rebar all the way around, then formed it up and poured a 6" stem wall to backfill against. I never have to worry about base boards rotting down the line. I also drilled the stem wall at 4' centers and put rebar into the slab.

 

[Firebrick43]

How big were the screws ?

My choice would be on inside of posts as I said, even if huge structural screws.

What was post c-c ? I'm talking 3.5 - 4.5 ft c-c as in thread above.

So w posts that close, and w my suggested full rough 2x lumber, holding up 2' height, you would not trust that even outside of posts w " fasten w a shitload of GRK RSS 3/8" x 8" ? structural screws w big flat washers under heads." let alone in the preferable inside the posts ?

Marc

They were 1/4 lags on the original, grk rss on my suggestion when put to the inside as I introduced them to him some time before the rebuild and like me he now uses them exclusively.

Post spacing was 8’. But as mentioned he place 2 about 4’ long treated 2x4 stakes so 2’. Without full length post going to the truss board and having the trusses resist the pushing force they are likely to be pushed as well.

The expansion of soils, weather by freezing or by moisture in expansive soils provides a tremendous force. As it retracts (from thaw or drying out) dust, debris, and soil fills the space and when it expands it pushes the wall further.

Even ICF walls which are the strongest concrete wall possible due to the foam slowing evaporation and allowing hydration to continue plus allowing easy and locking position of the steel reinforcement still requires pilasters at intervals.

The extra cost of post/holes starts making other construction methods logical from a cost perspective. Pole construction is inexpensive and good method of construction only when used in its normal manner. When you try to make it something it’s not it loses it economy fast.

 

[Firebrick43]

It's starting to look like a block & stick built project.

Remember unless block is grouted, bond beamed, and/or surface bonded it lacks the same strength from pushing.

By the time you do that a poured wall or icf wall can be the same cost. ICF for a short wall like this in a rectangular layout can be a diy project.

To really tie things together no matter which method, leave rebar sticking out the top(3’ long) of the wall every 4’. Bend this over to the inside and in the slab put rebar across the slab to the opposite side. This will tie and strengthen the wall from pushing out more than anything.

 

[greg13]

Got the green light for the build today! I am going to talk to a couple of barn builders that rent from us and get their thoughts on the floor.

Thanks Guys!!!

 

[kaymccampbell]

OK, so this idea has been used with mixed results. That is what I was looking for. If I did it I would go inside the 6x posts probably with 2x to retain the fill although I did consider using 2'x2' precast blocks to hold the fill. A guy had a bunch of 8' for $40 ea. Just a pain to transport and place them at 4000 lb each.

It's starting to look like a block & stick built project.

This looks like your best route. Lay down geotextile. Blocks on top. Couple the blocks together. Run drain tile inside and through the blocks in several places. Fill with compactable stone fill.