ᐅ Seeking Experiences with Exposed Concrete Staircases

Created on: 23 Feb 2020 07:13
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Pfadfinder87
Hello everyone,

I need your advice regarding our planned exposed concrete staircase.

We are having the formwork and pouring done on site. The plan is to afterwards treat the staircase with “béton ciré” to coat or finish it. Our staircase builder pointed out that there are two ways to do the formwork and that usually wood is avoided for exposed concrete because of the texture it leaves behind. In other words, the choice of formwork material depends on how the staircase will be treated afterward.

Special formwork means extra work and, accordingly, extra costs. I don’t want to cut corners in the wrong place but also want to avoid wasting money. So my question is:

Do you have experience with béton ciré and its coverage? How thick is the material applied and skim-coated? Can wood grain marks from the formwork be covered by it?

Alternatively, how do results look when the staircase is cast with special exposed concrete formwork? Does that create a comfortable, homey quality? The problem here is that the staircase will still be heavily used during the entire remaining construction phase.

I would really appreciate any experiences you can share. I will also reach out to the manufacturer of the béton ciré.

Thanks in advance!
Pfadfinder87
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Evelyn!
28 Oct 2020 13:01
I thought that if you want an exposed concrete staircase, a precast staircase is usually recommended rather than a cast-in-place staircase. That’s also what the construction company told me. I have no idea how it is actually made.
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Jann St
28 Oct 2020 21:34
Yes, the surface of prefabricated components is improving. However, there is a joint at the top that you will need to manage.

There are two different ways to manufacture a staircase in the factory. For exposed concrete, it should be “form-lined,” meaning the future underside is on top during production. This needs to be considered when placing the order.

Best regards
G
guckuck2
29 Oct 2020 06:38
Jann St schrieb:

Yes, the surface quality of precast elements is improving. However, you’ll have a joint at the top that you need to deal with.

There are two different methods to manufacture a staircase in the factory. For exposed concrete, it should be cast with a “negative form,” meaning the underside of the finished staircase is on top during production. This needs to be specified when ordering.

Best regards


That should be standard practice since you naturally want to see the formwork-smooth side.
From the "bottom," the staircase will, of course, look rather unattractive.

Which joint are you referring to?
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Pfadfinder87
29 Oct 2020 06:47
It is probably the joint at the connection to the floor finishes of the respective levels. But strictly speaking, you also have that with cast-in-place concrete, at least at the transition and material change.

We haven’t progressed further with our staircase yet, had to postpone it to avoid blocking the stairs. However, we will handle the finishing ourselves.
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Jann St
29 Oct 2020 07:49
Yes, exactly. If I construct them using cast-in-place concrete, I actually have only one joint, similar to the one at the change of room in the heated screed. A prefabricated element is usually acoustically decoupled, for example using Schöck elements. This joint is 1. wider and 2. fully absorbs the tolerances. If I don’t have a covering on the stairs, it is more difficult to visually bridge this joint.
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Evelyn!
29 Oct 2020 11:11
Ah, so I will ask again whether the staircase is cast with a negative formwork, but I would assume so if I want a concrete staircase with exposed concrete finish. The joint is then between the staircase and the floor covering on the level above, or in my case also at the landing, right? I should bring that up again as well. @Pfadfinder 87, it would be great if you could share your experiences when using Béton Ciré and doing it yourself, how well it works out.