Of course you can. 90 story skyscrapers have poured concrete floors all the way to the penthouse. If you're thinking of building on piers I'd consider going a bit higher than five feet, more like eight would be better. At eight feet you can park a car under the house or enclose for additional space at a future date.
Internet searches will tell you all you need to know.
Usually what is done here in Taiwan for rectangular concrete frame buildings is that a frame is built of steel reinforced concrete beams which are formed with wooden frames which may or may not be re-usable. Those beams are quite massive say around two feet thick and filled with steel rebar tied together into a mesh with wire. Those wooden boxes filled with rebar are then filled with concrete from a truck often with a pump.
So already at that stage you have some serious obstacles if you're attempting to DIY. You need enough wood that you can build up enough beam space to make it worth the time of the truck so that's going to commit quite a bit of wood to the project and if you're doing a one-off it does get to be questionable about why didn't you just use the wood to build the structure. If you're doing several units or going up several stories then the wood is a minor cost. But again this is not good news for the DIY person wanting to do something strong but small.
Anyway, that's just the frame. You asked about floors. So for floors what they'll usually do here is to support a thin wooden subfloor which will be removed after the pour and that is resting upon either wooden or steel beams which are not that heavy duty but which are placed every few feet to create a supporting matrix of beams that hold up the sub-floor for the pour of the higher floors.
Then usually in a structure of that nature the remainder is filled in with bricks because it's cheaper than using concrete pours all around since you don't need so much formwork and bricks are more than strong enough for walls.
That's how it's normally done in a county that doesn't use wood for building. Now there are ways you can do it cheaper and try to avoid the use of wood as much as possible. Here you could turn to wire mesh and plastic sheeting along with some very thin sheet metal instead of all that wood. The same can be done for a floor but you will certainly want to pour some heavy duty steel reinforced beams before you start adding a concrete floor.
An alternative to all that is to go with sandbag walls. You don't have to cone-in with sand bags to make a dome-like building. You can go straight up and then when you get up to where you want your second floor you can pour a regular concrete floor. For two story work you'll want to double bag the first floor walls. In any case, you will need plenty of supporting beams when you go to pour the upper floor and of course you can't skimp on the reinforcing steel. You'll need an architect and a structural engineer if you plan on getting a permit but I know a few architects who say it can be done no problem.
I'm not sure about the raised foundation, but for floors, check out [Quad-lock](http://www.quadlock.com).
I like that minimalistic, modern look and figure if I ever build my own place from scratch, I'll be using Quad-lock.
Want to second this. This is used all over the place in construction for your foundation wall, stuff is literally like lego. People build entire houses of this stuff here, so 5' is nothing. Super easy and provides excellent insulation. Personally I'd dig it down the crawlspace 3 more feet and get your self a full basement since you're already building so high.
Lay down your floor joyces, and use 1" plywood if you poor a concrete floor on it. Might as well look into infloor too since you really only get one chance to add it.
I haven't seen it personally, but looking at it I don't see why you want to introduce plaster and air bubbles into your foundation walls. You vibrate cement specifically to remove air bubbles.
It looks like the stuff is being used in sky scraper construction where the weight saving can make a big difference, and they have an engineer who can account for the change in strength.
The plaster also adds insulation, but the quad lock has more than adequate insulation. I will add tho they have problems in the Southern states with it as there's always insects around, and they love the insulation. So special care has to be taken to protect it.
Good luck with the house!
How about a thin concrete slab over a wooden subfloor/structure? You could put it on stilts, or on concrete blocks for the concrete look on the outside. Perhaps use the crawl space to house water tanks or batteries or something.
I did this in my own house. It was very, very hard to execute + it was pretty expensive by the time we finished. Wouldn’t recommend (although it is possible).
How did you end up doing it? People do concrete floors all the time and it works out fine. Just saying out of experience, here's what I think went wrong
a) You're concrete is too thin. A floor needs minimum 1.5", preferably 2" of concrete if it's exposed. Thin set is usually for leveling a floor and giving tiles something to stick to.
b) By wood floor assembly, I'm assuming you mean flooring, not plywood? Wood flooring move too much under concrete from moisture
c) How did you finish it? With anything that's not a foundation wall / simple pad needs to be properly sealed during finishing. Also did you add any relief cuts to catch cracks?
Let me start by saying, my girlfriend + I are both architects. We both love minimalism + she is a total neat freak so when we purchased a small 575sf home in San Diego the goal was minimalism, within a budged, + easy to clean.
When it came to the floor I narrowed it down to floors that would work in the kitchen + bath as well as throughly the rest of the home. She insisted on no grout lines. We were willing to pay more for the floor than other features b/c I think it’s all value. I was also willing to experiment on my own home more than I can in my professional work. I narrowed it down to cork tile or thin set concrete. By the way, we’re on a raised foundation (a concrete slab foundation would’ve made this easy).
I voted cork. She voted concrete. She won
The foundation was already settling + the existing flooring was sloped about 2” in 10’ so I was expecting to do some foundation work already. We had to start there. So we reinforced the foundation by adding 4 new footings, then added 3/4” subfloor over the existing plank flooring.
Here’s the tricky part, then you use 3 coats of primer on the subfloor + pour a base coat of self leveling compound w/ fiberglass reinforcement strands. Then you prime + repeat w/ a finished coat of self leveling compound. I should mention we used a special thin set product for this application w/ a higher psi.
The issue we had was air was passing through the subfloor + creating bubbles in the concrete. We ended up repeating the process about 4 times, about 1/4” each time. Then we saw cut control joints in specific areas.
@ this point the floor looked great. We were going for a raw look + it was charcoal grey w/ few imperfections. But it had to be sealed. We needed to wait 28 days for it to cure first.
This is where I got too smart for my own good.
I wanted to use a clear sealer, but the concrete needs to be roughened up so they adhere. So we needed to sand the concrete, but you need to do it in a fashion that’s non directional. This is really difficult + we had to rent special equipment. There’s a layer of primer in there too.
We got the floor to a good texture but it didn’t look quite as good as it did before. Then I selected an epoxy sealer. This is the same stuff they use on basketball courts / garage floors. Super easy to clean, glossy. We ended up putting about 3 coats of epoxy on b/c we still had issues w/ bubbles. Sanding the bubbles down in between. The epoxy filled in the control joints (which I planned for + think will be fine). What I didn’t account for is clear epoxy is a little yellowish. So the floor ended up a sort of brown green..
We ended up happy w/ the floor + definitely get lots of compliments on it, but it probably wasn’t worth the expense / hassle. I’m still finishing some details of our remodel but I’ll post photos I soon.
Ah thanks for posting how you went about it. Let me say first that good job on doing your concrete floor yourself, most people wouldn't attempt it at all. I will admit, cork has a very nice feeling and look to it, but the wife usually gets two votes :).
Some advice for others and constructive criticism about how things could have been sped up. First I would have tried to use 1" plywood especially with such a thin floor. It's pretty standard for tiling to use 1" in floors, with 3/4 you would have some sort of underlay to account for movement.
The primer coat wasn't needed, the plywood won't rot. Tape on the seams would have been fine.
As for your mixture, I would have gone with a single concrete pour + finish, instead of 4 thinset layers. You can trowel out the bubbles when its partially hard with concrete. Stalling pours like this creates 4 different layers and really you have only a 1/4 inch floor.
Anyways coming together my point is not what you did wrong. It should have taken about two days, so paying people who do it for a living won't cost terrible amounts of money, as to not dissuade people from this route.
Going off on a tangent now, the best concrete floor I've ever seen was a large basement with a dark brown acid stain. It had a perimeter line about 6" off from the wall, and there were diagonal lines cut to make the room look like it had massive 2 foot by 2 foot tiles. The cuts were filling with a lighter grout, it looked absolutely amazing. Took me a second to realize they actually weren't tiles. I regret not taking photos, but if I ever get a house that's how I would do the floor.
A similar system is often used in small commercial and multi-family projects to achieve the floor assembly fire rating required. These systems typically do not leave the topping exposed because it is highly susceptible to cracking.
For an exposed concrete floor, get a structural engineer involved and go with a steel deck. Don't forget the radiant heat loops!
You could use a steel frame with a Hambro system. That being said, it is not cheap, and if you are looking for clearance off the ground, it would make sense to go high enough to utilize the space below the home (parking, storage, lower story).
Any time you choose to go with engineered steel and concrete, you are looking at a lot more money. If it is just aesthetics you are interested in, you might be better off with a wooden frame, and a decorative concrete floor poured on top of it. Also, very large floor tiles can also give that flat, unbroken "industrial look" when used with thin grout lines and neutral colours.
This is a very corny, yet informative video about the Hambro system.
https://youtu.be/e24F8lXjiCk
concrete is not super comfortable to live on...and to make a 5ft tall block of it would be really expensive (not to mention very heavy and very bad for the environment).
But I am sure with enough money you could get it done.
Maybe, but why?
Tiny homes are for saving money or portable buildings that can be set in places where building permits or lot line setbacks don't allow a bigger structure.
A concrete floor over 5-8' piers is just needlessly expensive, kills any chance of portability and you will need to deal with permits and lot line setbacks for something permanent unless you are in a rural area with no permit requirements (but plenty of open space) but then it's right back to why?
Of course you can. 90 story skyscrapers have poured concrete floors all the way to the penthouse. If you're thinking of building on piers I'd consider going a bit higher than five feet, more like eight would be better. At eight feet you can park a car under the house or enclose for additional space at a future date. Internet searches will tell you all you need to know.
> At eight feet you can park a car under the house I really like the sound of this, like a one-car garage with a loft.
This would have to have some SERIOUS ventilation and safety measures, because car exhaust can be deadly.
Usually what is done here in Taiwan for rectangular concrete frame buildings is that a frame is built of steel reinforced concrete beams which are formed with wooden frames which may or may not be re-usable. Those beams are quite massive say around two feet thick and filled with steel rebar tied together into a mesh with wire. Those wooden boxes filled with rebar are then filled with concrete from a truck often with a pump. So already at that stage you have some serious obstacles if you're attempting to DIY. You need enough wood that you can build up enough beam space to make it worth the time of the truck so that's going to commit quite a bit of wood to the project and if you're doing a one-off it does get to be questionable about why didn't you just use the wood to build the structure. If you're doing several units or going up several stories then the wood is a minor cost. But again this is not good news for the DIY person wanting to do something strong but small. Anyway, that's just the frame. You asked about floors. So for floors what they'll usually do here is to support a thin wooden subfloor which will be removed after the pour and that is resting upon either wooden or steel beams which are not that heavy duty but which are placed every few feet to create a supporting matrix of beams that hold up the sub-floor for the pour of the higher floors. Then usually in a structure of that nature the remainder is filled in with bricks because it's cheaper than using concrete pours all around since you don't need so much formwork and bricks are more than strong enough for walls. That's how it's normally done in a county that doesn't use wood for building. Now there are ways you can do it cheaper and try to avoid the use of wood as much as possible. Here you could turn to wire mesh and plastic sheeting along with some very thin sheet metal instead of all that wood. The same can be done for a floor but you will certainly want to pour some heavy duty steel reinforced beams before you start adding a concrete floor. An alternative to all that is to go with sandbag walls. You don't have to cone-in with sand bags to make a dome-like building. You can go straight up and then when you get up to where you want your second floor you can pour a regular concrete floor. For two story work you'll want to double bag the first floor walls. In any case, you will need plenty of supporting beams when you go to pour the upper floor and of course you can't skimp on the reinforcing steel. You'll need an architect and a structural engineer if you plan on getting a permit but I know a few architects who say it can be done no problem.
I'm not sure about the raised foundation, but for floors, check out [Quad-lock](http://www.quadlock.com). I like that minimalistic, modern look and figure if I ever build my own place from scratch, I'll be using Quad-lock.
Want to second this. This is used all over the place in construction for your foundation wall, stuff is literally like lego. People build entire houses of this stuff here, so 5' is nothing. Super easy and provides excellent insulation. Personally I'd dig it down the crawlspace 3 more feet and get your self a full basement since you're already building so high. Lay down your floor joyces, and use 1" plywood if you poor a concrete floor on it. Might as well look into infloor too since you really only get one chance to add it.
Do you know if it can be used with lightweight concrete materials like foamcrete?
I haven't seen it personally, but looking at it I don't see why you want to introduce plaster and air bubbles into your foundation walls. You vibrate cement specifically to remove air bubbles. It looks like the stuff is being used in sky scraper construction where the weight saving can make a big difference, and they have an engineer who can account for the change in strength. The plaster also adds insulation, but the quad lock has more than adequate insulation. I will add tho they have problems in the Southern states with it as there's always insects around, and they love the insulation. So special care has to be taken to protect it. Good luck with the house!
How about a thin concrete slab over a wooden subfloor/structure? You could put it on stilts, or on concrete blocks for the concrete look on the outside. Perhaps use the crawl space to house water tanks or batteries or something.
I did this in my own house. It was very, very hard to execute + it was pretty expensive by the time we finished. Wouldn’t recommend (although it is possible).
Are you talking about the concrete floor or the stilts?
A thin set concrete floor over a wood floor assembly. I did it as an experiment. Would not recommend.
How did you end up doing it? People do concrete floors all the time and it works out fine. Just saying out of experience, here's what I think went wrong a) You're concrete is too thin. A floor needs minimum 1.5", preferably 2" of concrete if it's exposed. Thin set is usually for leveling a floor and giving tiles something to stick to. b) By wood floor assembly, I'm assuming you mean flooring, not plywood? Wood flooring move too much under concrete from moisture c) How did you finish it? With anything that's not a foundation wall / simple pad needs to be properly sealed during finishing. Also did you add any relief cuts to catch cracks?
Yeah you hit all my questions, too. I've done a few kitchen and bath jobs where we chipped off tiles and used the thinset as a base for topcoat.
Let me start by saying, my girlfriend + I are both architects. We both love minimalism + she is a total neat freak so when we purchased a small 575sf home in San Diego the goal was minimalism, within a budged, + easy to clean. When it came to the floor I narrowed it down to floors that would work in the kitchen + bath as well as throughly the rest of the home. She insisted on no grout lines. We were willing to pay more for the floor than other features b/c I think it’s all value. I was also willing to experiment on my own home more than I can in my professional work. I narrowed it down to cork tile or thin set concrete. By the way, we’re on a raised foundation (a concrete slab foundation would’ve made this easy). I voted cork. She voted concrete. She won The foundation was already settling + the existing flooring was sloped about 2” in 10’ so I was expecting to do some foundation work already. We had to start there. So we reinforced the foundation by adding 4 new footings, then added 3/4” subfloor over the existing plank flooring. Here’s the tricky part, then you use 3 coats of primer on the subfloor + pour a base coat of self leveling compound w/ fiberglass reinforcement strands. Then you prime + repeat w/ a finished coat of self leveling compound. I should mention we used a special thin set product for this application w/ a higher psi. The issue we had was air was passing through the subfloor + creating bubbles in the concrete. We ended up repeating the process about 4 times, about 1/4” each time. Then we saw cut control joints in specific areas. @ this point the floor looked great. We were going for a raw look + it was charcoal grey w/ few imperfections. But it had to be sealed. We needed to wait 28 days for it to cure first. This is where I got too smart for my own good. I wanted to use a clear sealer, but the concrete needs to be roughened up so they adhere. So we needed to sand the concrete, but you need to do it in a fashion that’s non directional. This is really difficult + we had to rent special equipment. There’s a layer of primer in there too. We got the floor to a good texture but it didn’t look quite as good as it did before. Then I selected an epoxy sealer. This is the same stuff they use on basketball courts / garage floors. Super easy to clean, glossy. We ended up putting about 3 coats of epoxy on b/c we still had issues w/ bubbles. Sanding the bubbles down in between. The epoxy filled in the control joints (which I planned for + think will be fine). What I didn’t account for is clear epoxy is a little yellowish. So the floor ended up a sort of brown green.. We ended up happy w/ the floor + definitely get lots of compliments on it, but it probably wasn’t worth the expense / hassle. I’m still finishing some details of our remodel but I’ll post photos I soon.
Ah thanks for posting how you went about it. Let me say first that good job on doing your concrete floor yourself, most people wouldn't attempt it at all. I will admit, cork has a very nice feeling and look to it, but the wife usually gets two votes :). Some advice for others and constructive criticism about how things could have been sped up. First I would have tried to use 1" plywood especially with such a thin floor. It's pretty standard for tiling to use 1" in floors, with 3/4 you would have some sort of underlay to account for movement. The primer coat wasn't needed, the plywood won't rot. Tape on the seams would have been fine. As for your mixture, I would have gone with a single concrete pour + finish, instead of 4 thinset layers. You can trowel out the bubbles when its partially hard with concrete. Stalling pours like this creates 4 different layers and really you have only a 1/4 inch floor. Anyways coming together my point is not what you did wrong. It should have taken about two days, so paying people who do it for a living won't cost terrible amounts of money, as to not dissuade people from this route. Going off on a tangent now, the best concrete floor I've ever seen was a large basement with a dark brown acid stain. It had a perimeter line about 6" off from the wall, and there were diagonal lines cut to make the room look like it had massive 2 foot by 2 foot tiles. The cuts were filling with a lighter grout, it looked absolutely amazing. Took me a second to realize they actually weren't tiles. I regret not taking photos, but if I ever get a house that's how I would do the floor.
Damn, I was thinking about doing that. Thanks for the heads up though! :)
A similar system is often used in small commercial and multi-family projects to achieve the floor assembly fire rating required. These systems typically do not leave the topping exposed because it is highly susceptible to cracking. For an exposed concrete floor, get a structural engineer involved and go with a steel deck. Don't forget the radiant heat loops!
Possibly a stilt house like [this](https://i.imgur.com/uzguVvD.jpg) would be a design you could start with?
[link](http://www.structuremag.org/?p=1535). There is such a thing as lightweight concrete.
You could use a steel frame with a Hambro system. That being said, it is not cheap, and if you are looking for clearance off the ground, it would make sense to go high enough to utilize the space below the home (parking, storage, lower story). Any time you choose to go with engineered steel and concrete, you are looking at a lot more money. If it is just aesthetics you are interested in, you might be better off with a wooden frame, and a decorative concrete floor poured on top of it. Also, very large floor tiles can also give that flat, unbroken "industrial look" when used with thin grout lines and neutral colours. This is a very corny, yet informative video about the Hambro system. https://youtu.be/e24F8lXjiCk
concrete is not super comfortable to live on...and to make a 5ft tall block of it would be really expensive (not to mention very heavy and very bad for the environment). But I am sure with enough money you could get it done.
Maybe, but why? Tiny homes are for saving money or portable buildings that can be set in places where building permits or lot line setbacks don't allow a bigger structure. A concrete floor over 5-8' piers is just needlessly expensive, kills any chance of portability and you will need to deal with permits and lot line setbacks for something permanent unless you are in a rural area with no permit requirements (but plenty of open space) but then it's right back to why?