Dry mix for post piers!

[Buelligan]

I did a search of the forums and found nothing so far.

Well we have some contractors building decks and pole barns who seem to just pour dry Sakrete into the footing holes and start building! I cannot seem to find anywhere in the code that allows this. Should it not be mixed properly prior to placement in the hole? They claim the "moisture" from the ground will set up the concrete, and even stronger than mixing it. What about when we are in a long dry spell? Are any of you familiar with this and do you allow it? Considering that we only do per-pour inspections I'm not sure we can control it at this point. But I am considering a post pour inspection to decrease this practice. So what are the thoughts of this wonderful community?

 

[Rider Rick]

Check with the manufacturer.

 

[Mac]

I checked with the manufacturer when I saw the entire unopened sack tossed into the hole. Were they ever surprised!

"We do this all the time" (bet nobody's ever heard that)

Nowadays the builders are calling for inspection, mixing & pouring.

 

[mjesse]

I actually had an inspector tell me to do it that way back in my early framing days!

I do know that if you leave a bag of sakrete out in the rain, it will turn to stone.

I'm sure it "works" but I can't say I recommend it.

Agree with RR, install per manufacturer's instructions.

mj

 

[Mark K]

Under the IBC I would reject it in a minute. Have not researced the IRC provisions.

Even if the concrete eventually hydrates you have the problem that untill it has done so and the concrete has come up to strength you cannot carry the loads. Thus you could request that they stop construction untill they can provide evidence that the concrete has come up to strength. How do you know what is the condition at the bottom of the hole.

There is also the concern that the dry material will fill all of the voids. Water provides a lubricant that is not availible when the material is placed dry.

 

[fatboy]

Manufacturers spec and instructions.......period.

 

[pwood]

Nimby!!!!!

 

[ICE]

Is concrete required? When I was young, I worked for Morton Buildings. We built pole barns. We drilled a hole through the post at the bottom and drove a steel dowel that stuck out four inches on each side. The holes were deep and we poured two dry bags and backfilled.

I wouldn't be surprised if they do it that way today.

http://mortonbuildings.com/buildings/farm-ag/

 

[MASSDRIVER]

On the "is concrete required" theme, some of the best, absolutly stout poles and posts I have set were in holes filled with what we call "butte rock", the local name for clean crushed rock about 2". I still build fences that way. Just dig the hole a little deeper than usual, put 6 inches of rock in, set post and pack the gravel in. It drains like awesome, and I defy anyone to pull it out of the ground. The rough edges of the crushed rock lock into the pole or post and it becomes one with the Earf. Never a rot problem either, and you build your fence or structure right away.

Brent.

 

[Rider Rick]

I checked with the manufacturer when I saw the entire unopened sack tossed into the hole. Were they ever surprised!"We do this all the time" (bet nobody's ever heard that)

Nowadays the builders are calling for inspection, mixing & pouring.

I have in Washington State.

 

[Buelligan]

Thanks everybody! So here is what we have so far. I called the manufacturer (Sakrete) and this is what their technical support stated. Absolutely NOT! Their product MUST be thoroughly mixed PRIOR to placement for any vertical loads. He said that their Fast Set and Post mix are the only ones meant to be used dry for POSTS ONLY (ex. fence posts or mail box posts). Any of their product intended to carry a load must be mixed according to the directions, period! So with that said we will now implement a post pour inspection prior to back fill, much to the dismay of said contractor! Again I knew this would be the answer but just wanted to get a feel for how many see this and how they deal with it. Again thanks for all your responses, very helpful as always.

 

[GCtony]

Under the IBC I would reject it in a minute. Have not researced the IRC provisions.Even if the concrete eventually hydrates you have the problem that untill it has done so and the concrete has come up to strength you cannot carry the loads. Thus you could request that they stop construction untill they can provide evidence that the concrete has come up to strength. How do you know what is the condition at the bottom of the hole.

There is also the concern that the dry material will fill all of the voids. Water provides a lubricant that is not availible when the material is placed dry.

Mark, unless you're in a desert, it's not if will hydrate, it WILL get very hard sooner or later. How do you know readymix out of a truck will come up to strenght at the bottom of the hole? Are you saying we do break tests on post holes? Not being a smart **** I just feel that you can't try to control and/or regulate every detail.

Pour about 12" of dry in the holes, shoot elevation, adjust dry mix for elevation, set cut posts, fill with dry, give it a drink of water and a few up and downs with a stick of rebar. Works great, since you end up with 12" of concrete under the pole. You can't get mixed concrete under the post so you end up with a post sitting on the dirt or a block with non-monolithic concrete around it. Sometimes the old methods give you better results than what someone wrote for a code book.

 

[Mark K]

GCtoney

My primary point was that we do not know how long it will take to hydrate the concrete. Until the cement has been hydrated all you have is dry mix in the hole. Was the pole building designed assuming that there was dry mix that had not been hydrated? Unless this was the case you should not apply significant loads to the structur until it was capable of acting as assumed.

It is assumed that the permit drawings said that there was concrete in th hole. Until the drymix has been hydrated you do not have concrete as was assumed and thus you have not complied with the approved construction documents.

While you may be able to get away with things in some cases, there is potential for real problems when the contractos decides to deviate based on what he "knows" works. Often times this supposed knowledge is mistaken. Prior to the North Ridge Earthquake the welders in the LA region ignored the welding specifications because the believed that they knew better. When the earthquake hit we found that these buildings did not perform as intended and one of the major reasons was the failure to follow the specifications resulted in weld material that cracked easily.

Who determines what gives you better results than was written in the code book?

If you want to be a cowboy get a job on a ranch but please do not get involved with building construction.

 

[ICE]

Who determines what gives you better results than was written in the code book?

You're a funny guy Mark K....yes sir, a real funny guy.

 

[Yankee]

Is concrete required? When I was young, I worked for Morton Buildings. We built pole barns. We drilled a hole through the post at the bottom and drove a steel dowel that stuck out four inches on each side. The holes were deep and we poured two dry bags and backfilled.I wouldn't be surprised if they do it that way today.

Farm & Agriculture Buildings | Pole Barns | Morton Buildings

so called "Pole Barn" construction technique is a valid and approval building method.http://www.awc.org/publications/dca/dca5/dca5.pdf

 

[jar546]

What is the load bearing capacity of the soil? Are you saying that they wood posts are sitting on the dirt and the dry mix surrounds the posts?

I have a letter from Sakrete stating that unless you wet mix their product, they cannot guarantee the psi strength of the concrete. I used this as an expert witness against a contractor.

 

[Mark K]

There is no disagreement that pole buildings can be constructed. The question has to do with certain construction proactices that are in conflict with the intent of the code and the approved construction documents.

While the letter from the manufacturer may be useful it is not necessary to reject the work until the questions are resolved.

 

[Yankee]

I believe the poles in pole barns can be designed/work like pilings, in that, they might not need any additional footings that we expect to see under posts. therefore. . . no concrete, or no "compliant" concrete.

 

[jar546]

I believe the poles in pole barns can be designed/work like pilings, in that, they might not need any additional footings that we expect to see under posts. therefore. . . no concrete, or no "compliant" concrete.

Many pole barns that I have inspected have a 2nd floor and up in the north there is a ground snow load so the load bearing capacity of the footers is critical. The wind uplift factor for the pole barns is the next toughest thing to tackle by finding a good design that resists uplift. I did an expert witness case last year against a contractor who did not provide the proper uplift design. The engineer on our side tore him apart along with the code official who approved everything.

 

[ICE]

An effective way to resist uplift on a pole barn is to close the doors.

 

[Rio]

Gee, why'd the roof blow off the pole barn? Well, I forgot to close the doors.....................

 

[ICE]

A day in the life of a piglet.

I was working on a pole barn in Illinois and could see a farrowing barn that we built on another farm. A storm blew in and three tornadoes formed. The wind was tremendous and I watched as people ran to the barn and closed the huge door at the down wind end of the barn. The upwind door was open and this created a 200' long wind sock. The whole thing popped out of the ground and lifted 20' above the ground. It moved along pretty much intact for 100' and then collapsed in a pile of rubble. Start to finish took maybe ten seconds but it seemed like slow motion.

The other barns were spared and none took a direct hit from a tornado.

So pigs do fly and closing the doors in the correct sequence makes a difference.

 

[GCtony]

GCtoneyMy primary point was that we do not know how long it will take to hydrate the concrete. Until the cement has been hydrated all you have is dry mix in the hole. Was the pole building designed assuming that there was dry mix that had not been hydrated? Unless this was the case you should not apply significant loads to the structur until it was capable of acting as assumed.

It is assumed that the permit drawings said that there was concrete in th hole. Until the drymix has been hydrated you do not have concrete as was assumed and thus you have not complied with the approved construction documents.

While you may be able to get away with things in some cases, there is potential for real problems when the contractos decides to deviate based on what he "knows" works. Often times this supposed knowledge is mistaken. Prior to the North Ridge Earthquake the welders in the LA region ignored the welding specifications because the believed that they knew better. When the earthquake hit we found that these buildings did not perform as intended and one of the major reasons was the failure to follow the specifications resulted in weld material that cracked easily.

Who determines what gives you better results than was written in the code book?

If you want to be a cowboy get a job on a ranch but please do not get involved with building construction.

I'm not usally one to take the bait but.... I miss read the original post. I personally would never dry set a pole barn, heck I would never build a pole barn with 4x4's stuck in hole with end grain resting on the ground that's surounded by a sponge (concret) Those things will never rot. (they should have pier footings) I was thinking more decks. A post resting on concrete, surounded by concrete.

Regarding your cowboy comment; 1) there are codes that are written by people that MAY not be qualified, just like in the construction industry, some contractors aren't qualified for everything. Just like inspectors, I've met some that souldn't be inspecting certian things. Maybe our society is too stubborn to admitt that someone may know something more than you. 2) If I built to meet code instead of doing things to meet my clients expecations and exceeding the code, I could make a whole lot more money.

"Who determines what gives you better results than was written in the code book?" This could be a very interesting topic for another thread, hearing peoples opionions from all sides. On second thought maybe not, architects, engineers and contractors aren't always welcome here.

 

[steveray]

R602.10.7 Braced wall panel support. Braced wall panel support shall be provided as follows:

1. Cantilevered floor joists, supporting braced wall lines, shall comply with Section R502.3.3. Solid blocking shall be provided at the nearest bearing wall location. In Seismic Design Categories A, B and C, where the cantilever is not more than 24 inches (610 mm), a full height rim joist instead of solid blocking shall be provided.

2. Elevated post or pier foundations supporting braced wall panels shall be designed in accordance with accepted engineering practice. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Don't know if this applies in your case,....but what does the engineer's stamp say.....