I have used some expansion bolts as well. I believe they hold up against outward forces much better than TapCons, but TapCons do just fine in sheer.
The expansion bolts I've used had long shanks of steel, with a cone at one end, and threads at the other. there were several sleeves around the shank. When you tighten a nut onto the threaded end, it forces the sleeves down the shank and then starts to crush them, forcing them to spread open and wedging them into the walls of the hole. I attached one of the railing posts of my deck to the house with these things, and they are incredibly rock solid. -- Blue skies. Dan Rossi Carnegie Mellon University. E-Mail: [email protected] Tel: (412) 268-9081
