wrote:
I am a member of the local natural foods co-op in the small town of
Bemidji Minnesota. They have a very small deli and the health
department is requiring them to install a vent hood. The manager
noticed that I am handy and has asked me to install the thing. He has
not bought it yet but is hoping to find a used one. I asked him if he
was planning to go through the roof but he said he wants to go through
the wall. I told him that I had never installed one but he said that
he wants me to do it anyway.

It is a commercial style building probably of 1920's vintage. I am
almost certain the interior walls and ceiling are plaster over lathe.
The exterior walls are brick and the roof is flat. There is a very
small space between the co-op and the neigboring building, just enough
for a ladder I'm guessing. They only use a small kitchen style stove
in this very small deli. I am a fine handyman and I figure I have all
the tools and skills neccesary to complete the job. I am, however,
concerned with some of the details. I want to do a very professional
job for the co-op especially since there are some damn fine women who
work there that I would like to impress.

Post a picture. If they're that damn fine, you might get someone on
here to do it for you!

What criteria should be used to select the hood? That is, how large
should the hood itself be and how large should the fan be? Do you
think it makes sense to go through the wall in this situation? I have
seen other hoods that vent throught a wall but not in such a small
space. What technique should be used to make a neat hole in a such a
wall or ceiling? Plaster and brick can be somewhat unforgiving
materials. How should the hood be attached to the wall or ceiling?
I'm thinking it should be screwed directly to the studs. Would wall
anchors be adequate? These people are super concerned with energy
efficiency. How can I mitigate any heat loss created by punching a
hole in the exterior of the building? What about the electric? I'm
guessing that the hood will need to be on it's own devoted circuit. I
think the panel is in the basement. Shold I just try to fish some
Romex through the wall into the basement? Thanks any advance for any
ideas or advice.

It's really not that big of a deal as far as punching the holes. Use a
chisel or screwdriver with a hammer and cut the perimeter of the duct
opening in the plaster. Then use a keyhole saw to cut the lath. Use a
hammer drill or rotary hammer to drill the brick, then cut the
sheathing with a keyhole saw or reciprocating saw.

The real deal with the installation is getting the details right. You
will need to look up your state's mechanical code and read up on the
exhaust hood requirements.
http://www.doli.state.mn.us/bc_minne...ding_code.html
You'll need to get a permit and there will be probably be at least one
inspection to verify the air flow.

Tell the manager that he should check with a used equipment or
restaurant supply house. It's obviously important to know what you
need before he goes out and buys something.

Venting into that side alley may or may not be a problem, depending on
whether there are windows on your building or the neighboring one and
whether your code/inspector will allow it.

Good luck with it.

R