Using a powerfloat or 'helicopter' and other matters

[Athene]

Ok, so we have cut out the rock from the floor and established a level base and the next job is to lay the concrete. We have sand, plastic membrane, 3cm insulation panels and metal reinforcement panels. We plan to raise the metal up from the insulation on small wooden blocks. We had a dummy run today with one panel as we thought that the metal might tear it up but no, it was depressed but sprang back, so that is OK we think. It is a very large area we are to concrete so, for practical reasons, we think it is better to have one pouring of ready mix. Reading the previous posts, people say it is better to have retardents added. Has anyone asked for these and what do you think of them? If we shuttered up small areas and kept adding to these and did the floor with cement from our own mixer would there not be a problem when the floor is tiled over in that it might split on the shuttered off section joints? Also has anyone used a powerfloat and did it help? Are they easy to use? We have bought some wider panels that we intend to cut up and place in strips around the walls, so that we will have a space to lay the metal framing for the plasterboarding. Do you think this is a good idea?

Any advice you can give us would be much appreciated!

[stewart]

Ok,

I'd forget the power float, they are not easy to handle if you've never used one, and you have to lay the floor and wait for the concrete to start setting before you can use it, the floor still needs to be flat and level, the powerfloat only trowels up the surface, so if your tiling straight onto the concrete you should be able to get a finish with a hand trowel. You say its a large area, how big?

I take it your using reinforcing mesh, i'd lay 50mm of concrete over the floor, sit the mesh onto this, then lay a further 50mm over the top, while the first lot is still wet!!!

Depending on the area, how hot it is, how many people are helping, etc, i would use a retardant in the mix, unless your used to laying floors you'll probably struggle to get it level and flat before it starts to set. I would lay a 600mm band of concrete around the floor perimiter, ensuring this is level, then lay further"screeds" running the longest lenth of the floor, at say 1500mm spaces. Once these are level and flat, its just a case of filling in the bays, using the screeds as a guide to rule off against and trowel up as you go!!! easy peasy.

Good luck!!!

Stewart. 

 

 

[Athene]

Thank you Stewart for that advice. I will relay it to him indoors after I have posted this and maybe he will need to ask you further if that is alright? We have 40 square metres to lay. Then a step up and 25 square metres. We planned to do the 40 first and then tackle the 25 later.

Again thanks for the advice!

[Dave&Olive]

hi

ok just a thought ..... you are going to mix by hand , beit in a mixer enough concrete to cover 40 m2  x 100 mm deep and lay it your self before the first part starts to go off..... who are you  ?? " William The Concreter " !!!  thats 4m3  or 7 tonnes !!

 I split this room 6x4mtrs into 3 strips and just managed the 2 outside ones in a day on my own , and I have done a fare few floors

     Dave

[IMG]http://i83.photobucket.com/albums/j311/daveolive/PDR_0054.jpg[/IMG]

[Alane]

Dave

You can tamp and level as you go. My wife and I did a 6.6mx5.5m floor on our own last summer using a mixer. It took us 9 hours plus but we worked through the room and you are right - the far side was hard by the time we had finished. I used a powered tamper which helped no end. Hard work and we are reasonably fit and used to laying concrete. We would probably have been better off if we had two people to level and tamp while the others mixed and barrowed but decided that it was achievable on our own. We've another slightly smaller sized room still to do and will probably get help with that but will tackle it on our own if we can't get help arranged when we need it.

My preference would have been ready-mix but the truck would have caused more damage to garden etc than we considered worth the trouble.

[Athene]

Thank you for this helpful photo Dave. No we are not mixing ourselves, we are going to have the concrete pumped into the first area - about 4.5 cubic metres of concrete. We have three men standing by to level. We will do the second area later. We have put the metal reinforcement up on small wooden blocks as Martin thinks that it maybe better to have it in the middle of the concrete and not resting on the insullation. Looking at your photo perhaps this is not necessary. I presume that the black vertical strips on the concrete piles are the shuttering?

No, we are not experienced at doing this and we really appreciate any advice we can get with it!

[Dave&Olive]

hi

 ok you do need to set the refo mesh in the centre of the mix , if you are having readymix arm yourself with a garden rake and  just lift the mesh up as the mix flows in . it`s handy to level the floor anyway .

   The black strips are angle iron set to the finish level of the floor , it`s to tamp the floor level because like I said I did it on my own .

               dave

[Athene]

Well the ready mix is ordered for Monday. We have bought these concrete levelling tools, like a rake but no teeth. It was amazing how the price shot up from concrete that was delivered in a heap and you barrow it in to delivery using a pump!

Thank you for your advice and I salute you - doing your floor all on your own - what a job!

[Athene]

Rejoice with us! We have a new concrete floor! Thank you all for your advice! Now one question - we put in lengths of wood to make bays on which to level the concrete. Do we need to take these out and refill with concrete? Martin thinks that perhaps if we don't they will make a weak spot in the floor and, after it is tiled, they may swell up and break open the concrete. How long should we leave the concrete before we do this? Tomorrow? Or do we wait till it is good and hard?

Forgive me but it is so exciting to see progress on our project! I am really happy tonight!