All over the internet I get different opinions. Contractors on site have different opinions.
The concern with pouring directly on the insulation is cracks along rebar during curing. This slab will be exposed, heated, with no control joints. The architect wants cracking to look natural rather than in straight lines. So we have 6" slab, low w/c ratio, 0.5% rebar ratio.
I see a lot of websites opposed to pouring the slab on sand due to the sand holding moisture which can travel through the slab into floor finishes over time. But is this a concern for exposed slabs? For a slab like this, I wonder if it may be better to put the sand over the insulation to mitigate cracking. What about the sand getting all lumpy while they tie all the radiant tubes and rebar in place?
Thoughts?
The concern with pouring directly on the insulation is cracks along rebar during curing. This slab will be exposed, heated, with no control joints. The architect wants cracking to look natural rather than in straight lines. So we have 6" slab, low w/c ratio, 0.5% rebar ratio.
I see a lot of websites opposed to pouring the slab on sand due to the sand holding moisture which can travel through the slab into floor finishes over time. But is this a concern for exposed slabs? For a slab like this, I wonder if it may be better to put the sand over the insulation to mitigate cracking. What about the sand getting all lumpy while they tie all the radiant tubes and rebar in place?
Thoughts?
