I like the light touch this guy brings to the subject, from the Polytech forum:
Way too small for eventual uses, but it's a good start if that's all
you have. But there are a lot of considerations. I have to go to
work so I'll touch on the points and they can be hashed out later, but
here's the basics:
If you do any welding, you need a fresh air makeup source
(preferably heated or with a heat exchanger if you live anywhere north
of Florida - and even there it gets chilly. Or air conditioned in the
And you MUST provide a vent hood over your welding table that
exhausts to the outside. Even if you have a variable speed fan so you
turn it down while doing relatively clean TIG welding, you still
produce fumes of nasty stuff that have to be removed. Oxy-Acetylene
MIG Fluxcore or Stick all make varying levels of bad stuff in the
smoke that has to be removed, and the metal fumes in the weld smoke
can cause severe health problems - zinc fume fever is just one.
Any ventilation blowers should have another control switch outside,
so they can be used by the FD for smoke ventilation in case of a fire.
The fan needs to be remotely mounted and the power and control wires
all run outside the extreme fire hazard area, so it keeps working.
Yes - but you'll need to do so much prep work to build a welding or
machining workshop under the house and do it safely that it would be a
WHOLE lot easier to sell that house and buy one further out of town
that does not have the restrictions on a shop outbuilding in the back
yard, or to build a new house from scratch (or a total
almost-ground-up remodel) that was planned for that use in the first
place. I'm thinking a concrete slab floor between the basement and 1st
floor as the ultimate firestop.
To get around the codes somewhat, you can just build an addition to
your existing garage to make it a 4-car, or add a second two-car
garage on the other side. After it's all built and the permits are
passed as a garage, then you can turn it into a workshop. (Creative
Interpretation.) ;-) Or go up - make it a 2-story detached garage
and you have the whole upstairs.
With a separate shop building 100 feet from the house you don't have
to be nearly as paranoid about life safety, because you don't have
people sleeping upstairs. If it burns down or blows up it can be a
serious annoyance, not a tragedy when a few people die.
Fire Safety: You need outside windows from all main basement rooms
for ventilation so the fire can go out instead of only up - or worse,
the heat builds until the floor above flashes over.
You need automatic fire sprinklers inside all basement rooms, a
water-curtain sprinkler head over the windows so the flames pouring
out the basement windows don't catch the house on fire. And an
outside sprinkler booster hookup for the pumper. This way if they
decide it's too dangerous to go inside, they can let the sprinklers
keep working on it.
Lots of extinguishers, including a bucket of Class D powder on hand
in case you ever machine magnesium or other highly reactive metals.
And a few strategically placed 1-1/2" hose racks with a fog nozzle by
the doors might prove useful if you can jump on a fire while it's
NOTE: You always put the fire stuff near the Exit door - that way
you have the exit behind you when you decide to fight or flee. Or you
try to fight then change your mind as it gets worse.
And you need an outside walk-up or storm door access to the basement
(two ways to get in would be even better) so the FD can get inside
safely to fight the fire without going through the house. And at
least one large access door helps when you want to get equipment and
supplies in and out, too.
You need a 2-hour rated ceiling and walls in all the basement rooms
(double 1/2" drywall or better), and a 2-hour commercial fire door to
the upstairs so the fire doesn't spread. You need proper fire dampers
in all vent and duct penetrations, and firestop collars on all
conduits and pipes.
You need heat (rate of rise) type fire detectors in the shop rooms,
and smoke detectors in the hallway headed upstairs - that way the
smokes shouldn't give false alarms as often, they are a door away from
the welding or paint spraying. The alarms need to be linked to a
burglar alarm with a dialer, so even if you work in the shop and leave
for the evening and something is smoldering, the FD gets called while
it's still small.
You need to keep all larger quantities of flammable gases and
liquids outside the house in a steel storage shed, including your
welding gas bottles - The odds are very low, but Google the terms
'acetylene deflagration' sometime and you'll get an eye full - the
bottle just decides to go BOOM!... There shouldn't be any more
flammable stuff stored inside than you plan to use that day.
And on a general basis, you will always have potential moisture
control problems in a basement - you may need a dehumidifier that can
run 24/7, and you may (depending on the water table and the
waterproofing of the basement walls and floor) be fighting a
never-ending battle against water intrusion and dampness.
You'll need to do a lot of soundproofing in the basement ceiling.
And any ductwork or pipes can still carry the noise upstairs.
Fine aluminum and steel shavings and dusts can catch fire all by
themselves, especially if you mix in a little sawdust. Add in some
This is why you normally do that work in a garage at home - because
by all modern building codes an attached garage is isolated from the
rest of the house by fire rated walls and a fire rated solid door,
there are ventilation ports at the floor and ceiling levels to prevent
fume buildups, there is a big door for easy access...
I gotta go, more tonight. I'll put out the verbal flames then -
probably just as many from the people who think I'm being overly
paranoid as from the people thinking I haven't gone far enough in my
safety considerations, but that's to be expected. It's that "There
are Old pilots, and Bold pilots, but few Old Bold pilots..." thing.
--<< Bruce >>--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700