"Pad Ready" Definition
"Pad Ready" Definition
(OP)
Hi,
Can someone tell me if topsoil can be used as fill to make a site "pad ready". For example, if the "pad ready" elevation is supposed to be 100, can the subgrade be 99.5, and the top 6" be loose topsoil?
Thanks, Kendra
Can someone tell me if topsoil can be used as fill to make a site "pad ready". For example, if the "pad ready" elevation is supposed to be 100, can the subgrade be 99.5, and the top 6" be loose topsoil?
Thanks, Kendra





RE: "Pad Ready" Definition
if the pad will sit there for a long period of time and is grassed and exposed to weather, then the upper 6" will likely need remediation anyway...however, i would not place organic topsoil in a building pad since it should probably not be there.
RE: "Pad Ready" Definition
If your pad ready elevation is 100, you should not use topsoil to "fill" the last 0.5' Rather, you should bring subgrade to elevation 100, and then place topsoil on top of this. This topsoil will have to be removed prior to constructing the building.
RE: "Pad Ready" Definition
In some cases where water migration due to capilarity is expected or soil heaving is predicted, coarse graded gravel or sand are left in loose state. I'm not totally agree with this solutions but I have seen some projects where these solutions are specified.
Ask to the geotechnical guy the reason of this specification on your project
RE: "Pad Ready" Definition
as far as topsoil (remaining after stripping the surface organics) placed as fill in roads or some slope areas, i see no problem with it as long as it is blended with cleaner soil, well compacted, observed as stable during placement and is capped with ~5' of well compacted, clean soil. the owner must acknowledge that there is a slightly higher risk of adverse effects by utilizing the material in this manner. and they must also acknowledge that buildings will never be located in these areas. and i'm sure that some on this board would object simply because of their location and localized geology. my statement applies to my part of the world where it is not a big problem as long as it is done properly and site conditions considered. and of course, there are limitations based on slope size, inclination, owner not willing to accept the risk, possibility of buildings moving or expanding, etc.
RE: "Pad Ready" Definition
RE: "Pad Ready" Definition
I hasten to add that topsoil has the tendency to soften more rapidly than the same non-organic soil when wetted, so in wet weather it is more of a problem in that respect. Yes, problems do occur when soft soil, including topsoil, is buried under pavements or other features. But the color and low organic content should not be the reason you strip it.
On the other hand, if we are cost conscious with our recommendations and not "c-y-a" type guys, this subject is brought to the attention of the owner with the cost differences involved, so he can decide for himself.
I first came to realize the lack of knowledge about the plus or minus factors involved when I saw contractors "get away with it" and it worked. The relative compact condition of the stuff makes all the difference (as with any soil)
More often than not, my experience has been that it is left in place (or even used as compacted fill) if the stuff is tight, with success.
RE: "Pad Ready" Definition
As a geologist, I do make the distinction between an actual topsoil and fill placed over the site that, with time, develops a weak soil profile at the surface.