On Mon, 21 May 2012 10:45:31 +0000, braanbatondi
wrote:

hi, i have prepared my shed base in my garden and now i am about to lay
a sand/dry cement (researching on this site i have read people using a
10 parts sand to 1 part dry cement mix).
i would like to know the following if anyone can help me please:

what type of sand/cement should i use?

The type appropriate to pouring slabs. You don't use play sand or
beach sand. Surely your concrete supplier will be able to deal with
this for you.

I own a concrete mixer, which is handy when doing posts and small
projects (not just for mixing it, but also to keep it from setting
while you're digging the next post hole, etc), but the amount of
concrete you need, you may as well drive off and purchase a load of
cement in one of those towable mixers. Let a pro deal with making the
mixture.

Cement is easy - if you're buying it as a separate component rather
than as a pre-mix concrete, you'd be getting "portland cement". Most
likely "Type II" (which in this case relates to reactivity with sulfur
in the soil).

how much do i need for a hole which is 10 ft by 10 ft and approx
4.5inches deep?

You mean, this is the size of the _slab_ you're making. Do the math:

convert your inch reference to feet: 4.5/12 = 0.375

10x10x0.375 = 37.5 cubic feet of fill

A 60# sack of concrete mix is 0.45 cubic feet of cured concrete, and
an 80# yeilds 0.60 cubic feet. So, assuming absolutely no losses to
sloppiness and prep, you'd need either (84) 60# or (63) 80# bags of
concrete (you should budget 5% more than that though - it'd suck to
run a bit short in the middle of a slab pour). Without the 5%
padding, that's a smidge over 5,000 lbs of bagged concrete mix - keep
that in mind while you're thinking about how many loads you'll need to
do in your SUV, pickup, or compact car, as well as how many bags
you'll need to lift onto the cart at the homecentre, then load into
the vehicle, and unload and mix at home, then dump into the slab
space.

Obviously, larger aggregate (rock) has more voids in it than sand, but
basically, you're looking at a (cubic) yard and a half of concrete
mix. Aggregate lends strength to the concrete, and fines (sand) allow
the surface to be trowelled smooth.

For a garden shed, why are you making the floor so thick? It's too
small to park a car in. You could shave 30% off your materials by
going 3.5" thick. Use reinforcing mesh (kind of like laying a wire
fence down on the ground).

Are you setting up for a drain (say, trench out and away and set up a
circular drain with cover in the middle of the floor, with the slab
gently tapering down towards the drain, or even just a trough drain
(like you might see in front of some garages), and are you setting up
to have a raised perimeter (where you might frame some 2x6' so that
the pour around the perimeter is higher than the floor), which would
keep your sill above grade. Going to set anchors around the perimeter
to affix the sills for the walls (use pressure treated lumber for
that)?

do i need to protect the walls of the hole with wood? (i havent and it
seems fine but im curious all the same=)).

Framing the slab helps to keep it well formed - generally more of an
aesthetic concern (say on sidewalks), but slag around the perimeter of
a foundation is a bother when you're doing rennovation work later
(such as trying to drop a conduit for power straight down the side of
a structure instead of several inches out because the slag is in your
way).