Posted: Fri Feb 18, 2005 2:54 pm
I'm just about to lay a 4" concrete slab in my living room over DPM and insulation, I wont be screeding the floor so want to get as level (and smooth) a surface as possible.
My question regards the method of laying strips over which I can use a tamping edge. Below are a few recommendations (mainly from the internet):
a) Fix wooden battens to the walls above the level of the floor. Make a dropped tamping beam to go between them such that its lower edge is level with the desired floor surface.
The disadvantages of this method for me are that the walls are rough slate and are not at all even which would make fixing a batten to it difficult.
b) The night before, lay thin concrete ridges at either side of the room and one down the center, which are carefully levelled to the desired floor surface. The next day when the main concrete is placed the ridges can be used to tamp across.
My worry here is that the ReadyMix concrete may not bond especially well with my mix which, due to the central ridge, cause cracks to form.
c) Use some 2"x2" wood supported on 2" pillars to create rails down the edges and center of the room over which to tamp. They could then be removed before the concrete is fully set and filled in with my own mix.
My only problems regarding this method is that I shall have to remove the strips before the concrete goes off but due to the shape of the room I shall have to be able to walk on the floor. Is this possible, how do I gauge the right moment?
This question is a bit off topic for the Brew cabin but you guys certainly know your stuff so I hoped you could throw some light on the issue.
I want to lightly float the concrete, do I do this as I tamp, or do I wait for it to go off a bit then wade back in? Is it possible to over work concrete, on small blocks I have laid previously I felt as though the water was coming to the surface as I trowelled it and the block now has a crumbly top surface.
Many thanks, Dave
My question regards the method of laying strips over which I can use a tamping edge. Below are a few recommendations (mainly from the internet):
a) Fix wooden battens to the walls above the level of the floor. Make a dropped tamping beam to go between them such that its lower edge is level with the desired floor surface.
The disadvantages of this method for me are that the walls are rough slate and are not at all even which would make fixing a batten to it difficult.
b) The night before, lay thin concrete ridges at either side of the room and one down the center, which are carefully levelled to the desired floor surface. The next day when the main concrete is placed the ridges can be used to tamp across.
My worry here is that the ReadyMix concrete may not bond especially well with my mix which, due to the central ridge, cause cracks to form.
c) Use some 2"x2" wood supported on 2" pillars to create rails down the edges and center of the room over which to tamp. They could then be removed before the concrete is fully set and filled in with my own mix.
My only problems regarding this method is that I shall have to remove the strips before the concrete goes off but due to the shape of the room I shall have to be able to walk on the floor. Is this possible, how do I gauge the right moment?
This question is a bit off topic for the Brew cabin but you guys certainly know your stuff so I hoped you could throw some light on the issue.
I want to lightly float the concrete, do I do this as I tamp, or do I wait for it to go off a bit then wade back in? Is it possible to over work concrete, on small blocks I have laid previously I felt as though the water was coming to the surface as I trowelled it and the block now has a crumbly top surface.
Many thanks, Dave