Hey,
I wanted to see if anyone had any tips on how to create a wall with concrete slabs WITHOUT the weight that a regular concrete slab would have.
The idea is to have a feature wall where you put up concrete slabs that are about 80 cm wide and maybe 1.20 high. You've probably seen something similar, as it seems to be everywhere these days.
However, I tried this with the thinnest reinforcement I could find and still got a thickness of about 4 cm, and then the slab weighed almost 60 kg. In other words, it's a real hassle to get these up on the wall; the wall needs to be reinforced, there might be problems with the floor considering the weight, etc. In any case, you can probably conclude that a regular concrete slab won't work.
BUT THE QUESTION IS IF THERE'S SOMETHING ELSE THAT LOOKS THE SAME BUT IS LIGHTER?
My thought was that you might try fiber concrete. I read about a technique where you use a core of Styrofoam and then chicken wire around it and then about 2 cm of fiber concrete cast on top of that. If this works, you can really reduce the weight, which could work to glue onto an unreinforced wall.
But the question is, what do you think? Could this work? AND MOST IMPORTANTLY, if it would work, how will it perform after you've put them up? They'll still be subjected to large forces, and the question is if they'll crack just from being glued to the wall? Any thoughts? Tips? I was thinking of also applying a thin layer of matte epoxy, where most of it would probably soak into the concrete, thus creating a stronger surface without destroying the raw surface you want the concrete to have.
Lastly, there's the question of appearance. I've never used fiber concrete before, how different does it look? Does it look like ordinary concrete?
Or does anyone have any other suggestions for reducing the weight?
The problem is, I want holes in each corner that are on pre-cast concrete elements, as I plan to put large bolts in these to further give the impression that they are genuine and raw.
A lot of text, but the point is to create a concrete slab with lower weight that can be glued to the wall.
Grateful for all responses.
Best regards
I wanted to see if anyone had any tips on how to create a wall with concrete slabs WITHOUT the weight that a regular concrete slab would have.
The idea is to have a feature wall where you put up concrete slabs that are about 80 cm wide and maybe 1.20 high. You've probably seen something similar, as it seems to be everywhere these days.
However, I tried this with the thinnest reinforcement I could find and still got a thickness of about 4 cm, and then the slab weighed almost 60 kg. In other words, it's a real hassle to get these up on the wall; the wall needs to be reinforced, there might be problems with the floor considering the weight, etc. In any case, you can probably conclude that a regular concrete slab won't work.
BUT THE QUESTION IS IF THERE'S SOMETHING ELSE THAT LOOKS THE SAME BUT IS LIGHTER?
My thought was that you might try fiber concrete. I read about a technique where you use a core of Styrofoam and then chicken wire around it and then about 2 cm of fiber concrete cast on top of that. If this works, you can really reduce the weight, which could work to glue onto an unreinforced wall.
But the question is, what do you think? Could this work? AND MOST IMPORTANTLY, if it would work, how will it perform after you've put them up? They'll still be subjected to large forces, and the question is if they'll crack just from being glued to the wall? Any thoughts? Tips? I was thinking of also applying a thin layer of matte epoxy, where most of it would probably soak into the concrete, thus creating a stronger surface without destroying the raw surface you want the concrete to have.
Lastly, there's the question of appearance. I've never used fiber concrete before, how different does it look? Does it look like ordinary concrete?
Or does anyone have any other suggestions for reducing the weight?
The problem is, I want holes in each corner that are on pre-cast concrete elements, as I plan to put large bolts in these to further give the impression that they are genuine and raw.
A lot of text, but the point is to create a concrete slab with lower weight that can be glued to the wall.
Grateful for all responses.
Best regards
Okay, here are some different suggestions:
1. Cast the slabs with EPS concrete instead to reduce the weight: http://www.epscement.com/
2. Cast slabs with fiber-reinforced self-leveling compound and self-leveling reinforcement mesh to make them thinner
3. Plaster/putty a foam board with house fix/repair mortar/plaster mortar depending on the surface you want and reinforce with fiberglass mesh. Finja Iso-Fin can be used as inspiration: http://www.finja.se/App_Resource/Page/file/betong/5017-1.pdf
4. Get fiberglass-reinforced concrete and you can cast down to centimeter thickness without reinforcement; search for GFRC Concrete on Google, it is widely used in the USA for the type of decorative slab you are looking for. Finja has a fiberglass-reinforced A-mortar for the Iso-Fin system which might work for this: http://www.finja.se/App_Resource/Product/PDF/PB/5585032-1.pdf
5. Make the sandwich construction you were thinking about but with foam/plaster mesh/repair concrete with fiber: http://www.finja.se/App_Resource/Product/PDF/PB/5511405-1.pdf
1. Cast the slabs with EPS concrete instead to reduce the weight: http://www.epscement.com/
2. Cast slabs with fiber-reinforced self-leveling compound and self-leveling reinforcement mesh to make them thinner
3. Plaster/putty a foam board with house fix/repair mortar/plaster mortar depending on the surface you want and reinforce with fiberglass mesh. Finja Iso-Fin can be used as inspiration: http://www.finja.se/App_Resource/Page/file/betong/5017-1.pdf
4. Get fiberglass-reinforced concrete and you can cast down to centimeter thickness without reinforcement; search for GFRC Concrete on Google, it is widely used in the USA for the type of decorative slab you are looking for. Finja has a fiberglass-reinforced A-mortar for the Iso-Fin system which might work for this: http://www.finja.se/App_Resource/Product/PDF/PB/5585032-1.pdf
5. Make the sandwich construction you were thinking about but with foam/plaster mesh/repair concrete with fiber: http://www.finja.se/App_Resource/Product/PDF/PB/5511405-1.pdf
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Many great suggestions!
Spontaneously, using the glass fiber reinforced concrete and casting just 1 cm thick sounds simplest, avoiding reinforcement.
But two questions arise,
1.) How will the surface look? Are the glass fibers visible on the surface? Or does it look like regular concrete after casting?
2.) How strong is glass fiber reinforced concrete? That is, if no reinforcement is used, can it still be guaranteed not to crack when mounted on the wall?
What do you think?
Helioz: Based on weight, appearance, and avoiding cracks. Which would you recommend?
Spontaneously, using the glass fiber reinforced concrete and casting just 1 cm thick sounds simplest, avoiding reinforcement.
But two questions arise,
1.) How will the surface look? Are the glass fibers visible on the surface? Or does it look like regular concrete after casting?
2.) How strong is glass fiber reinforced concrete? That is, if no reinforcement is used, can it still be guaranteed not to crack when mounted on the wall?
What do you think?
Helioz: Based on weight, appearance, and avoiding cracks. Which would you recommend?
1. No, with the repair concrete with fiber that I have cast, they haven't been visible, maybe if you diamond grind them. The surface looks like regular concrete. I haven't cast with glass fiber mortar.
2. I would still reinforce since the casting is so thin, I would use leveling compound reinforcement mesh, like these:
http://www.bygghemma.se/inomhus/golv-och-kakel/fast-och-fog/tillbehor/armeringsnat-for-golvvarme-%C3%B8-5-70-mm/p-176186-176186
Repair concrete with fiber has higher strength (50 MPa) than both regular fine and coarse concrete (40 MPa), so from that factor, it is better. See the product sheet I linked above. The glass fiber mortar is an A-mortar with 6 MPa.
Since the repair concrete is not particularly expensive (around 100 for 25 kg), I think you should buy a bag and do a test, both with and without reinforcement, to see what is acceptable for you. If you find it, also buy a bag of the glass fiber mortar and test it, you might not need more strength than that and then you can go even thinner.
Since you are casting as thin as you are and maybe not reinforcing, my suggestion is to build the casting forms in formwork plywood that you oil with cooking oil or real form oil, so there is less risk of cracking when you demold. The oil will not affect the concrete surface.
By the way, will the tiles be indoors or outdoors?
2. I would still reinforce since the casting is so thin, I would use leveling compound reinforcement mesh, like these:
http://www.bygghemma.se/inomhus/golv-och-kakel/fast-och-fog/tillbehor/armeringsnat-for-golvvarme-%C3%B8-5-70-mm/p-176186-176186
Repair concrete with fiber has higher strength (50 MPa) than both regular fine and coarse concrete (40 MPa), so from that factor, it is better. See the product sheet I linked above. The glass fiber mortar is an A-mortar with 6 MPa.
Since the repair concrete is not particularly expensive (around 100 for 25 kg), I think you should buy a bag and do a test, both with and without reinforcement, to see what is acceptable for you. If you find it, also buy a bag of the glass fiber mortar and test it, you might not need more strength than that and then you can go even thinner.
Since you are casting as thin as you are and maybe not reinforcing, my suggestion is to build the casting forms in formwork plywood that you oil with cooking oil or real form oil, so there is less risk of cracking when you demold. The oil will not affect the concrete surface.
By the way, will the tiles be indoors or outdoors?
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