[Greenbuilding] Advice about French Drain

[RT]

On Tue, 07 Jul 2015 18:54:28 -0400, Martha Beddoe <mebeddoe at twcny.rr.com>  
wrote:

>
> Is it reasonable to expect that one can dig up part of a French drain,  
> install the necessary piping, then return the drain to its previous  
> condition and have it >continue to function?

Martha;

Short answer : "Sure. Easy as pie."

Longer answer:  "French drain" can mean different things to different  
people.

As a "for instance" ...

I knew a French fellow who told me that where he hailed from (Maritime  
Canada) when building a foundation that sits directly on bedrock (as is  
the case in my neighbourhood and my home as well)  a "French drain" was  
made by fracturing the bedrock around the perimeter of the foundation so  
that water could be drained away. It's not an approach that I would have  
come up with nor do I think that it's something I'd do.

If your idea of a French drain is more along the lines of an excavated  
trench down to the footings of the foundation, walls of the excavation  
lined with geotextile fabric to prevent migration of fines into the  
washed, coarse stone that fills the excavation,  with a perforated  
drainage tile placed next to the footing, embedded in the stone ballast,  
then that's what is typically used for most foundations around here.

If, in digging your drain up to install the piping for heating system, the  
perforated tile (drainage piping) gets destroyed then inserting a new  
replacement piece and connecting it to the remaining tile isn't a big  
chore and the system should work just like the uncut tile prior.

Nor is replacing any washed stone ballast that may have had to be dug out  
or replacing filter fabric that got torn up/out.

All of the above doesn't require any fine detail work and would be pretty  
difficult to screw up.

While you have the foundation exposed, it would be a good opportunity to  
install a dimpled plastic membrane over the
foundation waterproofing to minimise hydrostatic pressure at the drainage  
plane.

                  https://www.armtec.com/product/platon-foundation-wrap/




-- 
=== * ===
Rob Tom DT7-64
Kanata, Ontario, Canada
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