Raised concrete floor using premade concrete planks

[canuckamuck]

I am making an outdoor toilet on a side hill out by our field. I decided to make it sit on stilts at the front and the back foundation rests in the hill. Its about 2 x 2.5 meters. It seemed a good opportunity to try using these premade concrete planks. They are about 50mm thick, 340mm wide and 2 meters in length. I got them in place and have cut out the plumbing holes and I am going to pour concrete on top now to strengthen and level it.

But I have two concerns. One is that a couple of them have a bit of a wobble when you walk on them.  Should I shore them up with a little mortar underneath first? And two, I don't know what depth of concrete to pour on top. I was thinking about 40mm would do it.

Anyone here used these planks before/ any tips?

Edited June 21, 2017 by canuckamuck

[Kwasaki]

Stop wobbles would be better.  

A top screen is usually between 50 - 100 mm on top of concrete plank flooring.

[canuckamuck]

Thanks Kwasaki, confirmed my thinking. It's not going to be fun getting mortar under those heavy buggers.

[Kwasaki]

If you can't move or get to them don't worry too much.

Just wedge them from the top.

The screen once in place should will set them.

 

[eyecatcher]

50mm connie is generally sufficient on top of the planks but dont go less.

Your aggregate content will be 40mm down so you dont want to be seeing it grinning through.

 

As for wedging or propping i dont think its nrcessary. It only wobbles when walk over one corner so when your topping is poured there is no way anything will ever wobble.

But dont forget to include some wraping fabric before the pour.

[Crossy]

+++^^^ and of course don't forget some reinforcing mesh in the concrete. I think our outhouses use 4" mesh, came on a roll from the builder's merchant.

[eyecatcher]

1 hour ago, Crossy said:

+++^^^ and of course don't forget some reinforcing mesh in the concrete. I think our outhouses use 4" mesh, came on a roll from the builder's merchant.

Thankyou for elabourating on my final sentence.

The thin reinf mesh is generally referred to as wrapping fabric/mesh

[Kwasaki]

3 hours ago, Crossy said:

+++^^^ and of course don't forget some reinforcing mesh in the concrete. I think our outhouses use 4" mesh, came on a roll from the builder's merchant.

Or made up thin strips of bamboo.  

[Kwasaki]

@canuckamuck  l knew you were gonna like that.  

[canuckamuck]

11 minutes ago, Kwasaki said:

@canuckamuck  l knew you were gonna like that.  

I've used bamboo more than once. In fact I have been told  that bamboo has been tested as a reinforcement material and they found that strips that are quarter round (so they are dished) have anti flex properties greater than iron. Sorry no link, just something I heard.

[Kwasaki]

Just now, canuckamuck said:

I've used bamboo more than once. In fact I have been told  that bamboo has been tested as a reinforcement material and they found that strips that are quarter round (so they are dished) have anti flex properties greater than iron. Sorry no link, just something I heard.

Your right buddy in Thailand it's very common all around our house many moons ago before Global hse etc and a like we used bamboo in concrete flooring and it's fine some 15 years on.

[sirineou]

why not pour a deck?  A toilet flr is probably small enough  where you can deck it out with plywood and pour the whole thing in one shot, columns, deck  and all.

A  monolithic pour.

Pour the pads in the ground.  you can do the erection with a couple of sections of scaffolding side by side , use shoes on the bottom and the top of the scaffolding,  On the shoes you put on the top,lay a couple pf stringers . and then ribs every couple of feet going the other way. lay plywood , cut holes where the columns go place the columns there, drop the steel in the columns, lay bottom steel and top steel  separated by some short of spacing steel, in the industry we use chairs.put stops all around the edge where you want the pour to stop and pour. if you pour a six to eight inch thick deck with enough steel you dont need beams.  I pour thousands of sq ft of deck with out beams in NYC high rise construction, only use beams on transfer points and other engineering considerations.

it sounds complicated but it is not. Erection and steel should take you a day, and you can pour in a couple of Hrs  . After pour if you strip the erection, you need to re-shore for  about twenty eight days until concrete reaches 75% curing

Personally I would not strip  and a couple of days later continue with your construction. If your erection can support your pour it can certainly support the rest of your construction. Many times we are erecting the next flr as soon as the concrete is dry enough to walk on.

Anyway, if you decide to go that way, PM me for more precise instructions.

 

 

 

[canuckamuck]

On 24/06/2017 at 8:33 PM, sirineou said:

why not pour a deck?  A toilet flr is probably small enough  where you can deck it out with plywood and pour the whole thing in one shot, columns, deck  and all.

A  monolithic pour.

Pour the pads in the ground.  you can do the erection with a couple of sections of scaffolding side by side , use shoes on the bottom and the top of the scaffolding,  On the shoes you put on the top,lay a couple pf stringers . and then ribs every couple of feet going the other way. lay plywood , cut holes where the columns go place the columns there, drop the steel in the columns, lay bottom steel and top steel  separated by some short of spacing steel, in the industry we use chairs.put stops all around the edge where you want the pour to stop and pour. if you pour a six to eight inch thick deck with enough steel you dont need beams.  I pour thousands of sq ft of deck with out beams in NYC high rise construction, only use beams on transfer points and other engineering considerations.

it sounds complicated but it is not. Erection and steel should take you a day, and you can pour in a couple of Hrs  . After pour if you strip the erection, you need to re-shore for  about twenty eight days until concrete reaches 75% curing

Personally I would not strip  and a couple of days later continue with your construction. If your erection can support your pour it can certainly support the rest of your construction. Many times we are erecting the next flr as soon as the concrete is dry enough to walk on.

Anyway, if you decide to go that way, PM me for more precise instructions.

 

 

 

@sirineou Sorry I missed your comment earlier. I had no idea that pouring concrete is your bailiwick. I would have picked your brain much sooner. Good to know though.

When I started this thread I already had done the foundation earlier and I was just getting back to it. So I did use the concrete planks and followed the advice given earlier. Every thing came out well. I have the walls up already and plumbing in. Now I am too busy to do the roof for a while, but who needs a roof eh? Anyhow thanks for all the advice.

[sirineou]

45 minutes ago, canuckamuck said:

@sirineou Sorry I missed your comment earlier. I had no idea that pouring concrete is your bailiwick. I would have picked your brain much sooner. Good to know though.

When I started this thread I already had done the foundation earlier and I was just getting back to it. So I did use the concrete planks and followed the advice given earlier. Every thing came out well. I have the walls up already and plumbing in. Now I am too busy to do the roof for a while, but who needs a roof eh? Anyhow thanks for all the advice.

always my pleasure to help, especially some one like you, whose participation in this forum I have enjoyed for many years .

Though I work for one of the premier  High-rise concrete construction companies in NYC  , concrete is not my "bailiwick"  though I do know some things about it.

It is a large operation with several trades involved. Form Carpenters, Lathers (rebar steel)  , Masons, and laborers specializing in each particular trade. Then we have engineers that pick up the points and lay reference lines and operating engineers for crains and concrete pumps.

The whole thing is engineered , concrete PSI , amount of steel in the pour , with pre-pour inspections to ok the go ahead, and pour and post-pout inspections with core samples etc.

I started as a Union concrete form carpenter, eventually became a supervisor,  I am now running their staging Yard where we store equipment , material , and make up forms . I am mostly involved in logistics now but my specialty is concrete forms.

The whole thing is perfectly choreographed and we are considered the kings of the two day cycle, ( a floor every two days)

below time lapse video of putting down a deck at one of the buildings I am working at now. 

[media]

 

Anyway I  do know some things about it and be happy to answer what I know, or If I dont know  I would be happy to ask one of our many experts in the organisation who know.