[Diy_efi] ever poured a large slab?

[Bernd Felsche]

On Friday 20 July 2007 10:50, Steve Ravet wrote:
> By large, I mean 25'x45'?  I poured a 10x20 slab last year for a pump
> house (had only ever done fence posts previously) and was pleasantly
> surprised at how it turned out, but that size can be screeded with a 12'
> board, and a hand troweled finish was fine.  I'm building a steel
> building workshop this summer and am contemplating pouring this slab
> myself.  I'm OK with the forms and the steel, but not sure if I'll be
> able to get a good machined finish.  

> Is this too big a project for a DIYer and some friends?

I'd hesitate; not only because I'm lazy but because the size means
that you'll either have to get a slow-setting mix (i.e. no
"accelerants" (catalysts)) or work very hard for a couple of hours.
I recently had a garage-workshop (~3m by 9m) built and the
professional who did the concrete floor was sweating heavily through
most of it ... at ambient temperatures below 10 degrees C; wearing a
light shirt and short trousers.

It's going to take a lot of cold beer to keep your friends cool.

As an aside, seeing that it's a steel workshop, it would be well
worth your while to insulate walls and roof with insulating blanket.

The bubble-wrap style of reflective insulation is only good with
still air around it, so steer away from that and towards the
glass-wool on heavy, reinforced aluminium foil. Such blankets come
in rolls and are sandwiched between the steel frame and the steel
exterior (wall and roof). The interior will be shiny aluminium that
can be left exposed unless there's the likelihood of mechanical
damage to the foil itself... in which case some form of lining can
be attached to the frame in such locations.

Besides heat, the blankets also reduce noise; not only transmitted
through the walls, but that reflected off the walls from sources
inside the workshop. So nobody will be able to e.g. hear your
obscenities as the screwdriver slips off a hose clamp and pierces
the webbing between thumb and index finger on your left hand.

-- 
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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