What flooring for direct slab without screed 1

[stripez]

To decrease dead weight. We don't want to put any concrete or dry pack topping or screed. The floor is level anyway.

This is how the bare slab surface looks like (about 3Mbytes picture so pls wait a while to load up).

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What can you put so the people waking won't feel the rough surface or it is visible? How about vinyl? What have you tried where you can just rubber glue or very thin adhesive?

 

[dik]

They have high build polyurethane coatings that will give you a mirror surface...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Tomfh]

You could grind it, or alternatively put down a floor coating.

 

[stripez]

We wont put any screed or topping over bare slab. And we cant grind existing slab of course because it is the structural slab.

What else besides polyurethane coating (you will spray this over the bare slab??

 

[MIStructE_IRE]

What’s it used for? Is it a warehouse with ultra precise level/flatness requirements or something less onerous than that? What’s the durability requirement of the floor finish? Are you turning forklifts on it or is it pedestrian access only etc?

 

[Retrograde]

Grinding a slab would normally remove less than 2mm of thickness, and it is done all the time on structural slabs.

 

[stripez]

It's an office floor. Owner doesn't want to add any screed. We would just put vinyl (like in following picture i saw at net) or similar material directly on slab. But how does vinyl look like when it's done directly on structural slab that isn't grinded? We won't grind the slab.

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[dik]

The irregular surface underneath will likely 'telegraph' through... that's why you have to start with a flat surface... either by coating or by grinding.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[stripez]

The irregular surface underneath will likely 'telegraph' through... that's why you have to start with a flat surface... either by coating or by grinding.

What is the thickness of screed do you usually use? If you use mortar paste over tiles. Because if it's too thin, it can crack and tiles would rise up especially during floor movement in seismic. Too thick and too much seismic load. The less the better.

 

[dik]

What's the amplitude of the roughness... give you an idea of the thickness... to be added, or removed. There are only a couple of solutions to this problem, and you have to look into implimenting one of them. If you cannot add a screed... then gypsum flooring likely won't work... You need a minimum thickness of about 1/2" to 1"...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[stripez]

They have high build polyurethane coatings that will give you a mirror surface...

I've been googling about polyurethane coatings for an hour. But I can't find them. Instead I read this about epoxy coating. Does it have the same negative effects like epoxy? Why not? So what other materials I can use on rough concrete slab surface? The slab is only 4" thick and we don't want to afford grinding it to avoid any mistakes like taking in 5mm or 10mm. Grinder locally doesn't know how to estimate.

https://learncoatings.com/applying-epoxy-paint-on-soft-uneven-concrete/

"Hardly a week seems to go by, and someone will ask me: I have this dusty and rough concrete surface , can I fix it if apply over with an epoxy coating?

My response is “Apply at your own risk”. The only valid reason why someone should apply epoxy on rough concrete is to eliminate dust and protect the surface from absorbing water or other chemicals.

If you do choose to go ahead, be prepared for the following issues:

1. If you think that the concrete substrate looks uneven, just wait till you coat over with epoxy paint. Epoxy is glossy and this will lead to all dents, cracks, holes and trowel marks of the concrete being revealed and magnified. The floor will quickly pick up dirt (since it will not be smooth) and very soon your coated surface will look dirty.

2. A common misconception is that by applying a high build epoxy coating (like a self leveling) on uneven concrete the floor will magically become smooth and level. THIS WILL NOT HAPPEN! (note the CAPS and Bold). You run the risk of consuming a lot of product with absolutely nothing to show for. You cannot use a runny product that achieves thicknesses of 3-4 millimeters to cover differences in the slab that could easily exceed 1-2 cm.
Furthermore what seems like “it just needs an extra bucket to fill that uneven area, can easily become 10 buckets. (and it still won’t be even!!)"

 

[BridgeSmith]

If you can grind it off just until it's smooth (i.e. you've only taken the high spots off), you haven't decreased the structural capacity, but you have decreased the dead load (slightly).

If reducing the thickness by a 1/4" or increasing the weight by 5 psf, by the addition of flooring, makes it so it's considered structurally inadequate, it already was.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[stripez]

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A roofdeck designed for a full floor was topped with 2" concrete topping (screed) over waterproof membrane (see photo above) over original bare slab underneath it. The roofdeck is covered already with metal roof and need to remove the 2" concrete topping. Since there was a rubberized membrane between bare slab and 2" coating with wire mesh. Will just lift off the wire mesh and the toppings will come off. I will make a car hydraulic jack welding to a tiny forklift. Anyone has seen a commercially available one so I don't have to go to the welding shop?

Anyway. After the 2" topping is removed. Will just use the bare slab. Even though live load is 100 psf (4.8 kpa). The 2" topping is equivalent to 25 psf (1.2 kpa). Owner doesn't want to put any topping due to cost and lack of budget. So will just use vinyl over bare slab. So if the bare slab is grinded 2mm. Can already put vinyl?

Has anyone of you ever encountered 25 psf (1.2 kpa) flooring? So heavy, isn't it?

 

[EdStainless]

Epoxy floor coatings are common, they are used in factories, food plants, schools, hospitals, and my garage.
There is some surface preparation required, and it is very necessary to get it right. Hire a contractor that does this for a living.
I have seen epoxy floors put in just for the cleanliness, but usually it is also to have a more user friendly (less harsh) surface.
If you mark the floor in a 1m grid pattern and put the exact same amount in each square you will end up with a floor that lays just like the concrete. I have seen applications where they did precision surveying of the floor and varied the amount of epoxy in each square to end up with a floor with less than 1mm variation over 30m.
If you use vinyl the concrete will need to be very smooth, every bump and dip will be visible through it.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Retrograde]

Another option is to level out the slab with something like Sikafloor® Level TOP (see attached). This can be applied as thin as 1mm.

Otherwise, if you don't want to apply a leveling compound and you don't want to grind the floor, just live with the uneven surface.

 

[stripez]

If bare slabs made as flooring, what is the fire rating?

And what flooring that is one, two, three and four hour fire rating?

What do you use?

 

[jayrod12]

The fire rating of concrete floors are a combination of overall thickness, and clear cover.

But you have only a 4" thick slab, and likely minimal clear cover to the bottom reinforcing, so it's likely that your current fire rating of the slab as constructed is less than one hour.

 

[Lomarandil]

To answer the side note, for tile floors (common in my part of the world), 1.1-1.2kPa is the standard flooring load allowance.

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just call me Lo.