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Site Imbalance

(This post was last modified: 07-30-2018, 04:29 PM by Ted Woods.)

(07-30-2018, 12:01 PM)mikeperik Wrote: I'm an owner/builder who bought Kubla Cubed to help with determining the site imbalance of my home build.  I was hoping I could use it to minimize the back and forth with the site plan engineer and my excavator.  The issue I'm having is that the Net volume I'm getting with Kubla Cubed is significantly different then what my excavator is coming up with in his calculation.  I tend to believe him since he has been doing it for 25+ years and he was spot on for another project he did for me.

I've attached the kubla file for this project.  I'm trying to eliminate the porches and garage from the fill imbalance since I will need to fill with gravel to avoid compaction of any soil in those areas.  So I'm really only looking at the cut of the basement and the grading as my points for determining the imbalance.

He is coming up with around 1000 cu yds of fill.  I'm coming up with about 200 cu yds of extra fill.    Interestingly enough if I move the features in the proposed grading down to the bottom, then I show a 1,000 cu yd fill imbalance.

Any ideas as to what I'm doing wrong?


I'm having some difficulty attaching the Kubla Project file.

Like for KSP file: https://drive.google.com/open?id=1_cgBjX...SnzXInNj9W

Hi Mike 

Welcome to the forums.  I think Tim is correct.  Looking at your project I can't see where a 800 cubic yards of discrepancy could appear unless your excavator is calculating to grade not including the basement and you are calculating to the basement level.  Moving the Feature Surface down in the calculation order in the same phase means it effectively overwrites the platforms so it will be doing what Tim suggested.  You can watch this video for more info on this.

However before being sure that this is the case there are some improvements that could be made to your project so I would recommend doing that first so we can get the full picture. The project is good with a good distribution of contours and points to define terrain.  However there are a couple of issues :

A) The side of the roads should have been defined with break lines to get a crisper edge. (I can show you how to do this).  Also there seems to be no consideration for surface material thickness (subgrade adjustment).  For instance the proposed driveway is gravel, what is the thickness of this gravel ?  On the plan the FF (finished floor) is marked.  This will be the the elevation of the top of the gravel, however an earthworks contractor will not be excavating to that level, they will need to excavate so when the gravel etc... is added it reaches the FFL.

The same is true of the garage and basement but I notice the levels of the platforms do not match the FF on these items.  Is this because you have already adjusted these ?  If so it is easier to put the construction thickness as an offset just to make it clear.  I recommend this video :

The porches and garage we will need to do in a special way.  Is it that you want these only to report cut, not fill.  We can do this, let me know if this is what you want.

Just to confirm, your results are Cut : 983.61yd³ Fill : 791.96yd³ Net : -191.65yd³ (cut)

Is your excavator getting 1000yd³ and a similar cut so near balance ? In which case there's only 208yd³ difference between your results, or is he getting 1000yd³ fill requirement Net : -1000yd³ (cut) I couldn't quite work it out from your original post.

Let me know and I will give you a call and I'm sure we can get to the bottom of it.  Also it is worth considering he may have been taking account of compaction\swell factor, but we will make sure the project is perfect first and then go from there.

Messages In This Thread
Site Imbalance - by mikeperik - 07-30-2018, 12:01 PM
RE: Site Imbalance - by TimO - 07-30-2018, 01:48 PM
RE: Site Imbalance - by Ted Woods - 07-30-2018, 04:23 PM
RE: Site Imbalance - by mikeperik - 07-30-2018, 05:51 PM
RE: Site Imbalance - by Leo - 07-31-2018, 10:49 AM
RE: Site Imbalance - by Ted Woods - 08-01-2018, 11:57 AM

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