Three years ago I had a porch/deck built outside of my kitchen. The construction is steel I-beams, and concrete topped with tiles, supported by four, square steel posts. The concrete is supported by a corrugated steel bed. The porch is 20' by 8', and also serves as a carport, since it is high off the ground.
About a year after completion of the construction, two problems appeared which I have been unable to solve. First, water leaks through the seam where the porch meets the house. I don't know if the flashing was installed properly, or even if it was installed at all. Caulking and re-caulking the full length of the porch have provided a temporary fix, at best. That side of the house is faced with vinyl siding.
Second, and perhaps more serious, a white substance (lime?) leached out of the concrete, and, when it rains, drips down on the inside of the steel I-beam frame on all four sides of the porch. When it drips on my car it is very difficult to scrape off. In addition, a white substance (perhaps the same as the other one) has leached upwards, and has discolored the grouting of half of the tiles. The tiles affected cover an area of 20' by 4', and specifically, the 4 feet which are farthest from the house, not adjacent to it. Tapping these tiles produces a hollow sound, indicating that they are no longer bonded to the porch.
Financially, I am the one who will be paying to fix this, as the contractor is totally out of the picture.