So I guess we were due for for a hiccup or two in what has so far been a problem-free install. Over the weekend we got a couple inches of rain and it exposed a couple problems I'd like thoughts on. The first is probably more minor, we've noticed that there are several places in the concrete decking where water pools, most noticeably on the concrete steps (see photo below). We don't have much in the way of freezing issues here in Austin but I'm worried that long-term standing water on places like the stairs might cause the concrete to degrade faster than normal. Is this something I need to be concerned about? If so, what can be done at this point?
Second, and more troubling, is that the rain caused the backfilled area next to the gunite shell where the Bobcat accessed the dig to settle considerably. Wouldn't be a problem except the edge of our decking extends out over the backfill, and now there's a 1-2" gap between the concrete and the ground that extends a foot or two back. (I've tried to capture in the photos below, not sure how well they turned out.) Clearly, this is an issue and I've let the PB know, but I don't know what I should ask him to do about it. Any ideas?
First of all let me say that I like that your PB took such good care to protect the surrounding shrubbery and area during the pour.
You are correct to expect that both the treads of the steps and the slab should be finished so that they have fall and do not hold water. Those issues are simply poor workmanship or lack of experience screeding, floating and finishing the concrete.
I only counted 5 pieces of rebar (maybe 6, it was hard to count even zooming in on the pictures and I think I saw one in one picture that wasn't in another) tying the pool wall and the entire slab together, that is not enough to support that slab if it were to be undermined.
It appears the corrugated pipe in the picture is coming from the downspout off your house, correct?
I think beside the fact that the fill was not adequately compacted, the poorly placed downspout pipe and the negative grading also contributed to the erosion of the fill. There may also have been a good bit of sand in that area of fill. You can see in the photos, that appears to be where the sand pile was. Sand does not make a good foundation, as it is prone to wash out.
It is very important that the downspout pipe be properly directed and the area be graded to achieve a positive slope away from the slab after the erosion is remediated.
I believe the slab was poorly prepped and finished, what concerns me more than the compaction issues is that the rebar is lying on and in some places buried in the fill. The rebar needs to be elevated so that the concrete is poured around it NOT on top of it. Did they do any further prep before the pour? Did they use any concrete wire or just the rebar? I also don't see any grade pegs, which are used to keep the surface flat and ensure fall when finishing. It doesn't appear to be a very wide slab, so they may not have needed them, it's hard to tell from the photos, but using them may have prevented the puddles you are seeing.
Also I don't see ANY expansion between the house and the slab?!? Perhaps it's there and I just can't see it in the photos. Does water flow freely away from the house where the slab is against it? That would be my biggest concern. Try spraying with a hose to make sure NO water is running toward the house as that could really give you issues in the future.
The second issue is going to be much easier to remediate than the first, especially if there is an issue with the expansion and rebar placement.