[RE-wrenches] Strawbale wall penetration

[Phil Undercuffler]

Having a fair bit of experience with bale, I ditto what Bill mentioned but
I'll add a simple way that I discovered to getting the inside and outside
holes to line up.

Bale walls are seriously thick, so standard extension bits aren't long
enough.  I found taking a 2 or  foot length of 3/8" rebar chucked into a
half inch drill works nicely for boring a pilot hole all the way through the
wall.  Once you have the pilot hole, it's a simple matter of drilling out a
hole large enough for your conduit on both sides of the wall.  Either use a
small bit to drill a series of holes around the perimeter and connect the
dots with a cold chisel, or use a hole saw that you don't mind sacrificing
on the plaster.  You don't actually have to "drill" through the entire wall,
as the straw can be pushed to the side.  I usually spin the rebar in the
hole while chunking it back and forth a few times to clear a path, then
thread the conduit through the hole using the rebar as a guide to be able to
find the hole on the other side.  It really helps to have a second person on
the other side, to help guide it in the final inches.

Rebar as a drill bit also works great with adobe walls.

If you do a lot of this, take a minute to grind down a flat spot on the end
of the bar or it will tear up your drill chuck.  Drill chucks can be spendy.
 Ask me how I know...


Phil Undercuffler



On Fri, Nov 19, 2010 at 11:27 AM, Bill Hoffer <sunengser at gmail.com> wrote:

> Benn
>
> I used PVC in the my bale walls with a Junction Box on both sides of the
> penetration to protect the penetration  (Outside a must!).  I used EMT for
> all my other wiring, but PVC seems better for an interior to exterior
> penetration where the heat conduction of the EMT may cause some damaging
> condensation towards the exterior of the bales.  I used a hammer drill and
> concrete bits to get through my stucco, it is tough stuff.  I used 2 "
> conduit so I had to make several smaller holes and knock it out by hand.   I
> did not have rebar in my bales, but heavyduty 6x6 mesh to get through, as
> would be expected I never was able to hit the middle of the grid, I just had
> to cut and hack saw when I hit something, pays to have a sacrificial bit to
> find the metal.  I then fashioned a home made bit out of the conduit and
> used that to get through the bales by hand.  That went pretty easy and will
> allow you to locate the rebar without damaging an expensive bit .  Hard part
> is lining up to get a good mark on the opposite side.  I used foam to fill
> any gaps, replastered around the pipe and fitting and caulked really well to
> seal against water on the outside.  I also located the JB on the outside of
> the building in a very protected area for additional security.  Water and
> straw bales do not play well together!  If anything I would favor a slight
> slope downward on the outside so if there is a leak it will not follow the
> pipe inward into the bales.
>
> Hope that helps!
>
> Bill
>
> On Fri, Nov 19, 2010 at 11:05 AM, benn kilburn <benn at daystarsolar.ca>wrote:
>
>>  Wrenches,
>> Short of contacting the builder, i'm looking for your experiences,
>> practices and "look-out's" for penetrating a strawbale exterior wall with
>> conduit.
>>
>> For the project in question there is currently a teck cable from a wind
>> gen entering the home by sharing a HRV vent opening that i want to fix (not
>> my original system by the way) and i will also be adding another penetration
>> for a PV array that i am relocating on the property. The original
>> penetration for the PV was done properly but its not in an ideal location
>> for the re-located array wiring.
>>
>> I'm wondering if it is as simple as using a hole saw extension to go thru
>> the ~16" wall and use an LB/box on either side.  I'm sure there is some
>> framework and/or rebar supporting the bales, how do you locate/avoid these
>> when there are no corners to measure from?  (it is a round home)
>> Any knowledge if PVC or EMT will react in anyway with the bales?  I'm
>> thinking that PVC would be best....?
>>
>> ... i am trying to contact the builder to address this, and also to ask a
>> few choice questions regarding the wiring methods (he?) used in the original
>> PV system set-up.
>>
>> Cheers,
>> benn
>>
>> DayStar Renewable Energy Inc.
>> benn at daystarsolar.ca
>> 780-906-7807
>> HAVE A SUNNY DAY
>>
>>
>>
>>
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>
>
> --
> Bill Hoffer PE
> Sunergy Engineering Services PLLC
> 2504 Columbia Ave NW
> East Wenatchee WA 98802-3941
> SunEngSer at gmail.com (509)470-7762
> Cell(509)679-6165
>
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