Redoing garage concrete floor - Page 3

> saka had written this in response to
>

> :
> jloomis wrote:
>> Hi,
>> Is the existing subgrade acceptable?
> Not yet. We are at this stage now, dig up the soil, lay the vapour sheet,
> tamper the sand and gravel.
>> Are you preparing that so that the "same" does not occur?
> That is the plan, how deep should the sand/gravel be? 1 inch ?
>> In any case, pouring concrete in a confined area presents problems.....
>> The same story as painting yourself into a corner.
>> There must be some doors....and or windows? (access)
> Yes there is a large roller door/side door that can be accessed from the
> front.
>> You can use overhead screed boards on the left and right sides so that
>> there
>> will be no stakes in the concrete pour.
> How exactly do these overhead screed boards work? since there is no
> formwork on the right and left hand sides.
>> Down the center a person can use a metal buried screed form, that
>> represents
>> top of concrete and rod off of that. It remains in the concrete and
>> acts as
>> a "cold" joint, or expansion / contraction line.....
> I found a site metalscreed.com so I now have an idea of what these are.
> Are these expensive? and could they be used on the left and right sides as
> well instead of using the overhead screeed?
>> I would make sure to use a "grid" of re-bar in the slab to
>> keep the concrete
>> together. I have had more luck with re-bar and cracking than any
>> concrete
>> wire or 6-6 10-10 mesh used.....
>> Also keeping the rebar at the right height is important so that it does
>> not
>> get imbedded in the sub-grade.
>> Are you using a vapor barrier?
>> If so, I always make sure it is deep enough to cover with a layer of
>> sand to
>> facilitate concrete pouring.....I never pour on plastic alone....
>> It can create problems with water and finishing.......
>> With concrete tools, I always jitter bug the top layer of
>> concrete......always.
>> It helps bring up the fines for the top finish, and set some of the
>> larger
>> rocks below top.
>> Using a float on a long pole is helpful in a confined area....
>> I have several mag floats for preliminary surface prep. and then steel
>> trowels on poles for finsih work.
>> In the past 4 years I have purchased a power float.....that goes on
>> poles
>> also.
>> It is a lifesaver......works wonderful.....can bull float the concrete
>> as
>> well as finish it all from outside the slab..........
>> It weighs 24# and has a small gas engine......works great.
>> Knee skids are also beneficial for finishing concrete in confined
>> areas....
>> I use metal, knee skids, and like "snow" skis.....you can
>> move out over
>> concrete without leaving board marks......of course there is a time
>> when
>> they are most successful as when the concrete is hard enough to use
>> them.
>> some of my inside pours I have pre-set boards high enough on the walls
>> that
>> a plank can span the area being poured......
>> You can "walk" a plank out and finsih an area without even
>> getting in the
>> concrete......an aluminum "rental plank works well......or a
>> 2x12.....or
>> scaffold plank.
>> I do this a lot for colored or stenciled concrete where the surface
>> cannot
>> be walked on......
>> have fun.
>> I am sure I have missed something......
>> jloomisconstruction and concrete
> Thanks for your post, it is very much appreciated don't feel so lost now
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