New Home Owners And Snagging Forum
Advice on buying a brand new home => Snagging and defects => Topic started by: Lozy92 on May 02, 2013, 12:19:38 pm
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I have posted here before and your advice has been great
My question is:- How deep /thick should the concrete floor be on a new build, ground floor??
Ours by the doors and edges is about 1cm cannot believe that this is right
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The thckness of the structural concrete floor normally depends on the type of floor and the spans involved.
The thickness of the structural floor is usually 150 - 225mm.
But in this case, I am assuming you are referring to the cement:sand floor screed which is laid on top of the concrete structural floor.
The floor screed should be reinforced with either chicken wire or have fibres as reinforcement added to the mix.
The generally minimum recommended thickness is 50mm.
The NHBC standards Part 8.3 - S2 state that
"THICKNESS: Screeds should be laid to the specified thickness"
"There should be at least 25mm thickness of screed above the highest point of any service pipe or insulation placed around the pipe."
"SURFACE PREPARATION: All surfaces should be clean and dust free. In particular, any traces of gypsum should have been removed.
Concrete surfaces should be wetted and brushed before screeding."
Screeds should not be as thin as 10mm anywhere, but especially at doorways, where they are almost certain to break up and fail.
You may also be talking about the levelling compound (aka Latex) sometimes used to smooth out rough surfaces.
This is applied as a liquid and can be any thickness often quite thin. It is very smooth and black in colour.
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Its been my experience inspecting that floor screeds are too thin in corners of rooms, in doorways and in large rooms expansion is not allowed for and should be to limit cracking.
I have had a number of homes with an incorrect mix of floor screed ....which when laboratory tested failed to meet requirements ...and builder had to replace the whole of the ground floor.
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It should be thicker in the corners and thinner in the middle of rooms as the floor beams are convex.