more concrete - tamping up to walls without guides?

[julianf]

Basically, how do you tamp / level a floor in a pre-existing room, where you want the concrete to go right up to the walls?

ie. no shuttering to tamp off

 

[eLuSiVeMiTe]

With difficulty. Why not use a screed mix. Use poles and a straight edge and float the troughs caused by the poles afterwards.

 

[eLuSiVeMiTe]

 

[Shox Dr]

Either screed (dry mix) or level battens either side, tamp to them and then remove and fill in

 

[rtbcomp]

Last time I did something like this I put the timbers in as normal, levelled the floor removed the timber after the concrete set and filled the gaps left by the timber, using the new floor as my level.

@Shox Dr beat me to it

 

[julianf]

That seems sensible enough - i guess i need to leave a bit of a gap behind the formwork, else ill never get it out when the concrete sets.

 

[julianf]

Before asking, id considered doing it the other way around - laying a 'ledge' all around the edge, letting that go off, taking off the forms, and tamping off the 'ledge'

I guess it would make little difference?

 

[Johnseat]

That seems sensible enough - i guess i need to leave a bit of a gap behind the formwork, else ill never get it out when the concrete sets.

If you have to tools then take the sides off at an angle so that the top is wider than the base to produce a trapezoid, the timber will simply pull out without sticking the concrete.

 

[rtbcomp]

That seems sensible enough - i guess i need to leave a bit of a gap behind the formwork, else ill never get it out when the concrete sets.

That's what I did because the wall was stone and very uneven.

 

[eLuSiVeMiTe]

The other option is to Batton the wall higher than needed and allow your tamping timber to hang lower if that makes sense.

 

[julianf]

The other option is to Batton the wall higher than needed and allow your tamping timber to hang lower if that makes sense. View attachment 108543

Now that ive looked at the picture for a while, im starting to think of Freudian ink spots...

Wall will not be batterned, so, although i dont understand, i suspect its not applicable to me?

(lime plaster will go on the stone direct)

 

[eLuSiVeMiTe]

Set your temporary battens on the wall 200mm above finished level. Use this to guide your tamp. Let the tamp hang down 200mm on a hanger of some description. Tamp your concrete and then remove battens when dry and you have one solid slab with no filling required.

 

[julianf]

Ahh, i get you now - thank you.

Im still not certain either way as to if im going to put the insulation under the slab, or on top of it - if i put it under, i should have it comming up, to thermally sepparate the slab from the wall - im wondering if i cut the insulation carefully, and secure it well, if i could tamp off that?

 

[eLuSiVeMiTe]

Check the video in post 3. The blue insulation around the perimeter is standard. Is there a reason you need a concrete floor. Screed is standard for the most. Can chuck fibres in too to increase strength.

 

[cocker]

Fill her up , level around the edges with spirit level/water level/lazer .
Tamp and trowel/float on the way out , don't overthink it -it's not a Swiss watch !!
Insulation and floating flooring on top .