Removing excess concrete on pillar....photo

[nzrick]

Two days ago the concrete for the three pillars next to the wall was filled 500mm too high. The rebar is fine but I need to remove the excess concrete.
 

Please can anyone suggest the best method? Disc cutter? .......jack hammer?
 

I am worried about damaging the structural integrity of the pillar and the foundations when removing the excess concrete. 
I'd like to get the pillar concrete to the correct height before the builders return next week
 

 

(incase anyone is curious why, there should have been a horizontal ground beam 500mm below the existing height of the concrete pillars but despite having been issued with detailed drawings the architect only gave the site foreman the floor plan). 5 days into the build and a major error!!
 

Edited September 3, 2016 by nzrick
spelling

[Anythingleft?]

A disc cutter with as many cuts as possible before breaking the rest off with a hammer and bolster, not many options for this

[sometimewoodworker]

Depending on how old the concrete is.

 

If more than about 5~7 days you can't do what you want, it will be too strong.

 

if only a day or two then a rotary cutter to score the surface an establish a level then an SDS drill in percussion mode. It looks as if you may have enough time to do this.

 

if the concrete is to old or strong then you will need to drill for some big, long rebar stubs and epoxy them in to key the beam in place.

Edited September 4, 2016 by sometimewoodworker

[canuckamuck]

I disagree.

Two days is too soon to be banging around on the pillar. You will create micro cracks everywhere.  It has to be cut away and jack hammered out, but it needs a few more days to cure some more.

 

[Anythingleft?]

28 minutes ago, sometimewoodworker said:

Depending on how old the concrete is.

 

If more than about 5~7 days you can't do what you want, it will be too strong

 

28 minutes ago, sometimewoodworker said:

if the concrete is to old or strong then you will need to drill for some big, long rebar stubs and epoxy them in to key the beam in place.

 

?? confused, if the concrete is too strong then how do you propose to drill it for the re-bar stubs?

 

Concrete is never going to be too strong to be removed especially here it just takes a little more time and effort the more it has cured, don't over complicate things just cut with a diamond disc and remove the pieces with a hammer and chisel

[Crossy]

Their error, they fix it!

 

Does the area flood? That extra 500mm elevation of the house may be an advantage

[sometimewoodworker]

1 hour ago, Anythingleft? said:

 

 

?? confused, if the concrete is too strong then how do you propose to drill it for the re-bar stubs?

 

You can always drill into concrete 

 

1 hour ago, Anythingleft? said:

 

Concrete is never going to be too strong to be removed especially here it just takes a little more time and effort the more it has cured, don't over complicate things just cut with a diamond disc and remove the pieces with a hammer and chisel

 

If the concrete is too strong then the only way to remove it is to cut through the rebar whic the OP dose not want to do

[sometimewoodworker]

1 hour ago, canuckamuck said:

I disagree.

Two days is too soon to be banging around on the pillar. You will create micro cracks everywhere.  It has to be cut away and jack hammered out, but it needs a few more days to cure some more.

 

 

Then there is little chance of it being separated from the rebar

[sometimewoodworker]

1 hour ago, Crossy said:

Their error, they fix it!

Unfortunately, though that is the correct answer, getting the architect to pay for the complete removal and replacement of the 3 footings is not very likely to happen IMHO.

1 hour ago, Crossy said:

 

Does the area flood? That extra 500mm elevation of the house may be an advantage

 

That could be the answer.

[Anythingleft?]

9 minutes ago, sometimewoodworker said:

Then there is little chance of it being separated from the rebar

 

I disagree having done it myself, it just takes a lot of time and effort as already pointed out, it's not impossible it just takes more time

 

But I would like to hear some of the numerous excuses yet to come from the architect just for laughs

[canuckamuck]

You can get the concrete out from between the rebar, it just requires strength and tools. A small jackhammer would poke that concrete out in fairly short order.

[MissAndry]

4 hours ago, Anythingleft? said:

A disc cutter with as many cuts as possible before breaking the rest off with a hammer and bolster, not many options for this

 

Don't forget the safety glasses, those flying concrete chips can really hurt.

[Kwasaki]

Can be difficult to answer without seeing full plans.

 

OP  quoted " Two days ago the concrete for the three pillars next to the wall was filled 500mm too high. The rebar is fine but I need to remove the excess concrete ".

 

Ques......Please explain how you know that..?

1. Are the plans showing an elevated floor section. ...

2.  Are you sure there is no more ground fill going in...
 

If it is a error it's a strange one.... " Please can anyone suggest the best method? "

Ans....If there is a  need to reduce height use only a " Disc cutter " a Disc blade for concrete and a  Disc blade for the rebar but let the builder do it.

 

OP quoted. " I am worried about damaging the structural integrity of the pillar and the foundations when removing the excess concrete. "    Ans... Yeah you should be. 
 

OP quoted..." I'd like to get the pillar concrete to the correct height before the builders return next week ".  ....Ans.. leave it alone, let them do it if it is required.
 

OP quoted. ( incase anyone is curious why, there should have been a horizontal ground beam 500mm below the existing height of the concrete pillars but despite having been issued with detailed drawings the architect only gave the site foreman the floor plan). 5 days into the build and a major error!!...

 

Ans...How do you know that is it on the floor plan maybe they haven't installed it yet if concerned ask the Architect.

[nzrick]

Thanks to all for the input. The area is subject to minor flooding, but the house design already accommodates for this. Ground level of the whole site has been raised well above historic flood levels, and then the house floor level is raised a further 800mm on pillars to both gain access underneath the house and

provide visual inspection against termites and further keep the house protected against future flooding.

 

The problem pillars are supports for the 4.5m overhanging mono-pitch, north facing, metal framed, metal sheet clad roof. These pillars (total of 4) were to be connected with ground beams and tied back with ground beams to the main house pillars. Later, these pillars will have vertical box section steel attached to support the steel framed roof.

 

The architect/builder, a lovely fellow, admits his mistake and has surprisingly agreed to my remedy, at his cost, as follows: The offending pillars will remain at their current height and, to maintain my carefully thought out and detailed drawings and design, the remainder of the pillars for the actual house will be increased in height by 500mm to correct the error. So, good result and the whole house will now be 500mm higher than planned. Phew !! Thanks again to all who have responded.

[Crossy]

Looks like a result.

 

If only our builder had made the same error we would have been 100mm above the 2011 flood, rather than 400mm under it

[nzrick]

20 minutes ago, Crossy said:

Looks like a result.

 

If only our builder had made the same error we would have been 100mm above the 2011 flood, rather than 400mm under it

 

You mean that wonderful stylish traditional design house with the (what my gf calls) "temple roofs" that you built in BKK? As a lurker here I followed your build but had no idea you subsequently had flooding problems. Hope you recovered.  I need to go back and check out your build topic! My gf's father has named my design "post-modern PTT" and keeps asking how much will I be charging for diesel !!

[Crossy]

2 hours ago, nzrick said:

 

You mean that wonderful stylish traditional design house with the (what my gf calls) "temple roofs" that you built in BKK? As a lurker here I followed your build but had no idea you subsequently had flooding problems. Hope you recovered.  I need to go back and check out your build topic! My gf's father has named my design "post-modern PTT" and keeps asking how much will I be charging for diesel !!

 

That's the one, "luckily" the 2011 flood happened during the build so we had no damage per-sé but the extra 500mm would have been welcome

 

EDIT Build thread is here :-

 

 

 Flood images here, the flood actually overtopped the sandbags and final high level pretty well covered the concrete mixer:-

 

Probably time for an update now the forum seems to be working reasonably well again, we've done a few things over the last 12 months or so.

 

[eyecatcher]

The extra cost borne by the architect doesnt end at raising the other columns equally.

I would be out with a list already....3 extra steps; tiled or timber lets say another 1000bt for tiles/labour/nosings.

and of course you could tell him that you now need to upgrade your pump for extra height. thats another 1k...maybe extra soilpipe, waste pipe, rainwater pipe and now your 4m extension ladder isnt long enough.

a bit more rendering on the columns, painting. extra balustrading becasue your deckings were not a risk before......it goes on and on.

 

for me the original problem, they would have been asked to break out all the coloumns back to the pad, tie in the ring beam cages they missed and shutter them again. it would have taken 90 minutes with a small jack/kango.

 

of course the builders cant see further than their noses; I hope you can.