MarkH Posted September 16, 2016 Share Posted September 16, 2016 Our slab is devided into a 4.8m by 10.5m section and a smaller 3.8 by 6.3 part. The architect long ago suggested two transverse movement joints in the large section but my dad - the ex-cowboy builder - reckons there's no need. The slab is 100mm, steel reinforced. My research so far suggests the easiest route would by to use a 'groover' to cut a partial depth joint in the top 25% of the slab (before it is fully cured). Am I on the right track? Link to comment Share on other sites More sharing options...
PeterW Posted September 16, 2016 Share Posted September 16, 2016 If you are putting UFH pipes in it then be very careful about movement joints. Suggest they go under a wall if you do put them in and then make sure there is sleeving where the pipes go through the doorway. Link to comment Share on other sites More sharing options...
IanR Posted September 16, 2016 Share Posted September 16, 2016 What's the reason your architect wants to split the slab? Mine's 25.5m x 18.5m and was cast without joints. Link to comment Share on other sites More sharing options...
MarkH Posted September 16, 2016 Author Share Posted September 16, 2016 42 minutes ago, IanR said: What's the reason your architect wants to split the slab? Mine's 25.5m x 18.5m and was cast without joints. Was yours reinforced Ian? Link to comment Share on other sites More sharing options...
Oz07 Posted September 16, 2016 Share Posted September 16, 2016 Conventionally it's just there too control cracking. You might get away without if steel reinforced. I put them in at every weak point. Doorway etc. Also try and split tiled rooms with the direction you will be tiling. If theres no ufh then no reason not to put in for how long they take Link to comment Share on other sites More sharing options...
ProDave Posted September 16, 2016 Share Posted September 16, 2016 The house I am wiring at the moment has the floor slab cast as one, with no expansion joints. There are two large cracks visible in the slab, and not at the points where you would think was a "weak point" As he is planning to polish the concrete and varnish it, an expansion joint or 2 would probably have been better than 2 cracks. Link to comment Share on other sites More sharing options...
IanR Posted September 16, 2016 Share Posted September 16, 2016 (edited) 50 minutes ago, MarkH said: Was yours reinforced Ian? It is, 100mm thick (+ ring beam) mesh reinforced, with UFH, installed over EPS. We've got a couple of small surface cracks, but as we didn't have plans to polish weren't concerned about the risk of minor cracks. Edited September 16, 2016 by IanR Link to comment Share on other sites More sharing options...
duncgee Posted September 16, 2016 Share Posted September 16, 2016 Are there any concerns regarding air tightness if the floor slab cracks? Link to comment Share on other sites More sharing options...
MarkH Posted September 17, 2016 Author Share Posted September 17, 2016 12 hours ago, duncgee said: Are there any concerns regarding air tightness if the floor slab cracks? I guess the dpm takes care of that. Link to comment Share on other sites More sharing options...
Oz07 Posted September 17, 2016 Share Posted September 17, 2016 13 hours ago, ProDave said: The house I am wiring at the moment has the floor slab cast as one, with no expansion joints. There are two large cracks visible in the slab, and not at the points where you would think was a "weak point" As he is planning to polish the concrete and varnish it, an expansion joint or 2 would probably have been better than 2 cracks. Theres also maximum bay sizes with certain types of concrete. The agilia mix I usually use for instance. Like you say, a neat saw cut following on from a nib or wall, or in the centre of a room looks proper, a wonky crack doesn't Link to comment Share on other sites More sharing options...
Oz07 Posted September 17, 2016 Share Posted September 17, 2016 i wouldn't worry about it if it was being covered and has reinforcement. Link to comment Share on other sites More sharing options...
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