Building a covering over an existing concrete slab will require that you secure the structural supports to the concrete. A typical building scenario involves using wood posts to support a roof over an existing concrete patio. Concrete anchors are an effective method for attaching the post to the concrete, and this strategy can be used in any number of situations where a post needs to be attached to a concrete slab.
Purchase a masonry boot anchor of appropriate size for the post you will be attaching at a local hardware or home improvement store. For example, if you will be attaching a 6x6 post, purchase a 6x6 masonry boot anchor and hardware (concrete sleeve anchors and bolts, and lag screws).
Mark the locations for the centre of your posts on the concrete slab. Set the boot anchor on the concrete slab, centred on the mark you made. Mark through the holes in the boot and onto the concrete, to indicate the drilling locations of the holes for the anchor bolts.
Use a heavy duty electric drill or hammer drill equipped with a masonry bit to drill holes for the anchor bolts on the marked locations. The packaging for the anchor bolts will indicate what size bit to use, and how deep to drill the holes. Blow out the debris left in the holes using a turkey baster.
Drop the concrete anchor sleeves into the holes you drilled, and position the boot over the holes. Insert the bolts into the holes and sleeves, and fasten securely with a wrench. Do not over-tighten it.
Place the post in the boot, and plumb it using a level placed on the vertical sides of the post. Attach the post to the boot using the provided lag screws driven through the holes in the sides of the boots and into the post.