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Hi Guys, I have a number of freezer floors about 800 sq.ft each. The slab is 6” thick concrete on insulation and vapour barrier. There are some cracks and there is minor damage to the surface of the floor. There is no evidence of heaving or any issue with ice damage under the floor. What would be the pros and cons for adding a sand layer on the existing slab, polyethylene sheeting on the sand and pouring another 6” slab? Ceiling height is not an issue.
Have you consider contacting a Floor Coating Company? They can remove surface damage and coat the floor. I have had this done many times in Cool Rooms. Make sure you have a reputable, experienced Contractor.
I'm by no means a freezing room floor expert.
By freezer floor, do you mean freezing as in -22F or in that area?
Talking to a friend that does concrete and he said that as long as your existing floor is clean and dry, you can pour a new layer of concrete straight on top as long as it's at least 5 cm thick (2" or so).
But if you have any existing cracks, they will probably carry over to the new slab.
He wasn't sure about your solution to construct a new floor on top of the existing floor, as he'd never done anything like that.
His initial observations were, and I'm paraphrasing here :)
In Norway a freezing room floor would be built like this:
-gravel
-Reinforced Concrete 10-20Cm (4-8") (sometimes even with heating) main slab, this has to protrude 60 cm or so outside the freezing room, at least enough so that the wall is resting on this plate. This is also the concrete foundation that the walls rest on.
-moisture barrier
-Insulation, minimum 20cm (8 inches) of extruded (polyethylene?) designed for long term load
-Reinforced concrete 10-20Cm (4-8")
He said, as long as there are no issues with frost heave or apparent damage to the vapor barrier, and it's only cracks and surface damage that it would be more cost efficient to a hard/soft resin concrete repair to fill in the cracks and damage rather than to pour a new slab and then have the new slab and old slab move/work against each other because the original slab now has added insulation from the cold and will start to expand and contract in a different way and that might break the vapor barrier.
I've had him on the phone while typing this :)
I have to say that you said "ceiling height is not an issue", my first concern was floor height :D
Guessing the floor from inside to outside is level now, and then you add sand, insulation and another 6" of concrete, you would elevate the floor by maybe 10-15" so my first concern were forklifts or pallet jacks having to negate that :)
He just sent me a link http://www.kwikbond.com/blog/concret...torage-floors/
He said "something like this, but find a company that does this for a living and have them come in and assess the damage to the floor and give a proper quote"
Thanks for the info. What I meant when I said ceiling height was not an issue was that all the surrounding floors would be raised by the same amount and the existing ceiling was high enough to accommodate the increase in height.
Thanks for the link and I will explore the option of the floor repairs.
Tycho:
Excellent Advice!
Especially "He said "something like this, but find a company that does this for a living and have them come in and assess the damage to the floor and give a proper quote"
you're better pouring straight on top of the old floor without the sand or any other material in the middle
use strong concrete (we'd call it a C40 mix locally) have it with fibres (extra cost is negligible) and add plenty of rebar mesh to it
I've done that a lot in factory floors, never had a problem with any of them, anything from 2 to 4inch thick, some sloping from 4+ inch down to 2inch, over drain covers, drains, underground tanks, forklifts bumping over them all day etc. etc.
important question tho, are there just long thing cracks running along the floor? any pattern to them? - you need to look for the difference between cracks due to expanding/contracting and a problem with the floor underneath moving
get a concrete company in and they should sort it no problem
sometimes you have to cut a line in the floor, wait for the floor to set and then fill the line back in... to allow that tiny bit of expansion/contraction
also might be able to with an epoxy floor covering... will be much cheaper/easier/quicker