Removing 7' Of Soil To Property Line (Neigbor Slab On Grade) - Habitat Project

personalt

I am a GC helping out on a habitat for humanity project in Jersey City NJ. We are developing a property which has soil with above allowable amount of lead. The remediation plan if we want an unrestricted deed is to remove soil to 7' deep, propery line to property line. Below 7' is good soil but everything above 7' is fill that has a high lead content. If we dont dig down 7' we would have to cap the side and back yards with pavers or some other sort of cover and note this bad soil in the deed. We would really like a clean deed if we can find a way to make it possible.

My concern with excavation is that the neighbors house along one property is slab on grade. Their house goes right to the properry line. Along the other property line is a house with a basement. However, the foundation wall is red brick that looks bowed inward based on a visual inspection.

I have done some underpinning projects previously but on those we only went down a foot or two.

There is some pictures of the houses along the lot line here if you click 'Site Cleanup'
http://www.habitathudsoncounty.org/p...lery/index.php

There is some arial pictures of the lot at the url below. It is J shaped lot in the middle, as you can see there are 3 differnt properties that are right along the property line. Well you can't see the propertiy lines but the two properties on the main street and one one the side street all go up to the property line. We would need to go down 7' basicly all the way around.

http://maps.live.com/default.aspx?v=...9152&encType=1

My gut feeling is that we are trying to build affordable housing and that underpinning in this project is not going to keep it affordable.

We would need to underpin 50 feet along the left side, 91 feet along the right, plus 60 feet along house from the side street. We would be looking at around 200 linear feet of underpinning.

At this point we need to decide if we should even consider trying to remove the full 7' of soil. If we do we do decide to consider it further we will take it back to the architect to recommend and engineer and a excavator to do this work. If not we will move foward with a restricted deed. My gut says that removing this much soil is not practical for us based on the fact that we want to keep the housing affoardable. At this point I am just to see if we would eliminte the idea of digging all this soil out or if we should bring an engineer in.

My questions at this point are to help me decide if we should even consider thinking more about this.

-Do we need to underpin this, or is there a way we could do this with temp. shoring? Our building foundation would be 6' below grade about 4' from the property line. Could we shore along the property line until our new foundation is built and then backfilled with new/clean soil?

-If we would have to underpin is it realistic to underpn someone elses property? I know NJ building code has rules that says if you are doing work along the proerty line you must preserve the neighbors property. But I assume that doesnt give you permission to underpinning someone elses property?

-Our goal is to build affordable housing. We have gotten quotes for soil transporation and disposal (no excavation) at around $60K with one company willing to donate $30K of the cost. The 30K we are paying for soil removal is a decent hit for our budget. I know that when I underpinned a house 1' over 60 linear feet it it was a big job. I can only imagine how big a job underpinning 200 linear feet 7' down is. Can anyone provide any information as to the scope of this job? Could this be considered a 20K, 50K, more project I am not looking for anything detailed, just the most general ballpark.

Any information that anyone would provide would be great. Lending my expertise to habitat is very rewarding. We have a great team but none are are PEs or excavation guys. Our next goal is to either decide to forget going down or to look for people who can help us make it happen. any insite greatly appreciated

Blas

What type of soil? Clay, sand, sandy clay? all these have different oversize stability requirements. If it was a clay site I would say you could get away with a half to one oversize and maybe they would let it slide because the majority of impacted fill was corrected and that small amount would not be a problem. If it is a sand site I would get some prices on soil solidification and see if that fits into your budget better. GOOD LUCK

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