concrete wall finish spec

huangyhg

concrete wall finish spec
hi everyone,
i am working on a school that for cost reasons the concrete basement walls will be left exposed.  what are the options for finish grades?  how is that correctly specified?  i am assuming we will have a mid-level finish: wall being planar,no bulges, blemishes, honey combs, some regular formwork joint and tie pattern and such
thank you
eric mcdonald, pe
mcdonald structural engineering, pllc
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eric,
first, make sure the walls are waterproofed from the outside and do not compromise on the waterproofing.  you'll only have one shot at it.
next, make sure the walls are formed and placed within a reasonable finished surface tolerance, like 1/4" in 5 feet or similar.  you've already touched on the blemishes, honeycomb, etc.
you might also limit the w/c ratio of the concrete to help prevent a lot of water channels in the finished concrete surface against the forms.  let them get workability from plasticizers, not water.  use air entrained concrete.
you could also specify a form liner to get you a particular surface texture if you like.
check aci 303.1 "cast in place architectural concrete".  though your concrete is structural, you might get some ideas on finishes from this recommended practice.
tie pockets can be dry packed or left exposed for architectural interest.
thank you everyone!  this has been helpful.
eric
eric mcdonald, pe
mcdonald structural engineering, pllc
include in your specifications the procedure on how to rub and finish the walls.  it is often a grey area...
on the matter of tie pockets, these can be arranged in a regular pattern, too.  they also have plastic caps to close them and also can use a caulk material and they don't have to be flush with the wall surface.
dik