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Re: Footing protection

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On 20 Dec 2006 at 7:34, Donald wrote:

> I?m constructing a building Northern Cal now and am interested in some
> strategies for protection of footing holes. From now until April, I?m
> likely to get rain every day or two. I?m thinking of overexing the
> footings about 4 inches deeper, draping visqueen down into the hole
> and out around it a few feet and then filling the bottom with 4? of
> gravel. In this way, rain water can be pumped cleanly and the walls of
> the footing excavation are protected from sloughing into the hole and
> caving, rebar is protected from mud, the rodbusters have a clean
> gravel surface to work on and all, hopefully will be well. Footings
> are poured over the gravel and the visqueen remains in place after the
> pour.
> Anyone see any structural issues with this idea? Anyone have a better
> strategy?
>     Don

Don't dig them until you are getting ready to place the concrete.

Leaving a hole open over the winter is asking for all manner of problems.
You'll still have to excavate the holes in the spring and will likely have to
over-excavate both depth and sides to get to undisturbed soil. 

If you are in an area that freezes, then you will get frost expansion of the 
soil over the winter and you will either need to excavate that expanded 
soil or compact that soil.  In either a non-freezing environment or in a 
freezing environment, you are going to get rain erosion into the hole, 
which will tend to fill the hole with debris and make the sidewalls grooved, 
requiring excavation.

If the holes are already dug, you can fill them and re-dig them in the spring,
or cover them with rigid foam insulation and plastic to try and prevent 
freezing and water ponding.  If the holes are in a low spot, you will have
more difficulty keeping them from filling with water and eroded debris.

Good luck,
Lloyd Pack

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