Rugs, Carpets and Carpeting - Transition from carpet to tile...help.

I'm going to carpet a small addition that sits on a slab, and I don't know how to transition from the carpet to the slate tile in front of a sliding glass door. The section is about 8 feet long, and I don't want to go carpet, wood strip, stone (or carpet, metal strip, stone). At the same time, I don't want anyone stepping on a tackless strip. I've heard of a z-strip, but I can't find them on-line, and I don't know if they can be installed on a cement slab.

Also, where do I find cushion and high R-value insulating fiber board? The big box stores don't seem to have much of a selection, and all I find on the internet are wholesalers.

Thanks!

Z bar is the answer to your dilema. One reason you may not be finding it is because it isn't called Z-strip. Yes, it can be used on concrete and is used in conjunction with tack strip. If you're using a cheap or thin enough carpet that the pins can be felt through it, pound them over with a hammer after the install. By "cushion", I'm assuming you are talking about pad. You should be able to get that from the same place you get your carpet. Are you planning to put the fiber board under the carpet? If so, have fun getting the tack strip to hold.