# Building a square pillar on a round sonotube



## oxygenrace (Jan 15, 2013)

I have been asked to build a 16.5" x 16.5" pillar on a 16" diametre sonotube pier. Is my best approach here to pour a square base around the sono-tube? how do i anchor it to the tube and how deep should it be? other solutions?

thx


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## dom-mas (Nov 26, 2011)

skip the project and ask them to pour something that makes sense


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## JBM (Mar 31, 2011)

What is the pillar made of? Stone?


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## oxygenrace (Jan 15, 2013)

the pillar will be brick. its a neighbour up the street, so i'd like to help.


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## oxygenrace (Jan 15, 2013)

what about cut the pier down by a foot and put a one piece concrete chimney block or a 16x16 pier block on the pier. I could fill the block solid and then lay it on the sono-tube.


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## griz (Nov 26, 2009)

How tall & what's it for?

You wouldn't buy a size 10 shoe when you wear an 11 would you?.:whistling


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## JBM (Mar 31, 2011)

How about you make a form to sit on the tube and pour it at the same time? A couple pieces of re rod on the top would finish it up.


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## Chris Johnson (Apr 19, 2007)

Why use a sonotube? 

Dig down, proper footing, build a square box as your 'sonotube' make it 15.5x15.5" square, put your brick pillar on top.

Depth? What's your frost depth? If none, at least to solid virgin soil


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## oxygenrace (Jan 15, 2013)

the pillar will surround a 6x6 that will support a porch roof. My masonry will not be load bearing. the sonotube goes below the frost line. my pillar will be about 4' tall. I would have built a footing a and a square pier but the tube was already poured.


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## Chris Johnson (Apr 19, 2007)

1/2" steel plate mounted on top of the sonotube, get it galvanized and keep it 4" above grade, code is 6" but the gap will look ridiculous.


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## FrankSmith (Feb 21, 2013)

oxygenrace said:


> what about cut the pier down by a foot and put a one piece concrete chimney block or a 16x16 pier block on the pier. I could fill the block solid and then lay it on the sono-tube.


The reason the pier is deep is not for support but to get below the frost line. If the load being supported was inside a one foot deep footing would do the trick. If you do what you have mentioned the frost will get under the square block and heave everything. Pour the proper footing.


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## oxygenrace (Jan 15, 2013)

FrankSmith said:


> The reason the pier is deep is not for support but to get below the frost line. If the load being supported was inside a one foot deep footing would do the trick. If you do what you have mentioned the frost will get under the square block and heave everything. Pour the proper footing.


I could taper the transition between the round sono and the square block and put clear gravel around the top of the pier to allow drainage and movement around the pier in the event of frost heave? It s not an ideal situation by any means. I need to transition to square below ground because the base of the other pillars I am matching are parged square at the base.


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## cdkyle (Jul 12, 2009)

Build a 16" round brick column ?


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## Diamond D. (Nov 12, 2009)

cdkyle said:


> Build a 16" round brick column ?


Or

Corbel, round to square.

D.


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## brunothedog (Sep 8, 2013)

I dont understand what the problem is?
just brick it as asked.
round to square, square to round, whats the difference?


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## dom-mas (Nov 26, 2011)

Cut it flush with grade, dowel and epoxy a couple pieces of rebar minimum of a real 8" in and bend them inside a 8x 15.5 x 15.5 form and pour it, maybe rough up the top of the sonotube to get a good bond and throw some weldcrete on for S&G's. clear stone below the form for sure


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## oxygenrace (Jan 15, 2013)

Thanks for the replies. I am going to use a cottage block laid on the sonotube. It is a steel reinforced 20"x20"x4" concrete pad sold at the local brickyard for $15. What's even better is I was given two hats, two shirts and a handful of pencils for just talking to the right sales guy. Oh and i had my 5 yr old daughter with me too. I figure I will grind a chamfer on the underside after cutting it down to 16x16. Clear stone around the base










Sent from my iPhone using Tapatalk


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## dom-mas (Nov 26, 2011)

you need a mechanical bond between the square an the round. that close to grade and water WILL get underneath and heave it


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## oxygenrace (Jan 15, 2013)

dom-mas said:


> you need a mechanical bond between the square an the round. that close to grade and water WILL get underneath and heave it


alright, thanks for the advice. I'll pin it with some epoxy and threaded rod.


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## oxygenrace (Jan 15, 2013)

oxygenrace said:


> alright, thanks for the advice. I'll pin it with some epoxy and threaded rod.


hey dom-mas, where's a good place in ottawa area to buy 14" masonry blades (diamond for limestone)?


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## dom-mas (Nov 26, 2011)

in Kinburn there is a tractor supply that sells 14" diamond blades for $70 or something. not the best blades but for 1/3 the price it's pretty good. Otherwise, HD sells them or I often go to Rental Village. they are a Stihl dealership and I always seem to need an air filter and blade about the same tme


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## fjn (Aug 17, 2011)

Never drew it out to see the overhang involved with your situation however,this brief Tech. note may help.

http://www.maconline.org/tech/consumers/clinic/overhangs/overhangs.html


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## dom-mas (Nov 26, 2011)

a 16" circle has an area of approx 201 sq inches. A 16"x16" square has an area of 256. Unfortunately ALL of that 1/4 missing area is on the outside in the corners (obviously) building square in a similar sized circle just doesn't work


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## fjn (Aug 17, 2011)

dom-mas said:


> a 16" circle has an area of approx 201 sq inches. A 16"x16" square has an area of 256. Unfortunately ALL of that 1/4 missing area is on the outside in the corners (obviously) building square in a similar sized circle just doesn't work





I knew it would not fit.:laughing: Question is will the overhang be within the prescribed tolerances of that tech note ?


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## dom-mas (Nov 26, 2011)

No.  The corner bricks will have more than 1/4 of their area just hanging out, but it won't be all in one plane like corbeling, it will be the entire corner


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## owattabuilder (Sep 2, 2013)

Anything hanging over the tube will be susceptible to frost heave. Nothing will tie it down and prevent it. You may be able to use some foam below the corners tomprovide a crush zone that will keep the frost from heaving it. There is no good solution other than replacong the tube with a square footing as big as the pier you want to build.


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## JBM (Mar 31, 2011)

Cut the top 8" of the tube off and lay a chimney block on it......

leave the dirt away from the bottom of the block. 

you guys crack me up sometimes.


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## dom-mas (Nov 26, 2011)

JBM said:


> Cut the top 8" of the tube off and lay a chimney block on it......
> 
> leave the dirt away from the bottom of the block.
> 
> you guys crack me up sometimes.


That will heave and crack within 5 years guaranteed. maybe 10 if it's off grade by 8: or more


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## brhokel606 (Mar 7, 2014)

dom-mas said:


> you need a mechanical bond between the square an the round. that close to grade and water WILL get underneath and heave it


Dom-mas is exactly right! You can epoxy and pin all you want but from what I understand, the footing should be bigger than the object it is sitting on it. No matter how much you smooth the transition, I will want to pop off the footing. 

Just do what Chris Johnson suggested, form a square footing yourself.

My 2 cents


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## JBM (Mar 31, 2011)

Meh I dont think so. Put some bark mulch under it.


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## Fouthgeneration (Jan 7, 2014)

Dig around the sonotube down to frost depth, remove cardboard,wash column, form a 16" square at grade,wrap with chicken wire, pour with concrete, no worries, no demo......


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