Red Green wrote:

Laying out some tile. Carpet will be replaced after the tile.

http://tinypic.com/view.php?pic=244s70h&s=4

Is the carpet typically fastened to the riser (glue or tack strip?)
then tucked behind the tile edge. Or does the carpet sit on top of
the tile then maybe some kind of molding at the junction?

Tucking behind the tile would seem to be better looking to me but
maybe because there's not much depth to tuck it tends to fray or
something.

Tile is 3/8" thick, riser is wood, tile base is slab.

I'm asking because I need to know whether to butt the tile againtst
the riser or leave an amount of space for tucking. If so, how much
space?

Butt the tile up against the riser, but leave a little space, then
caulk it. The space you're leaving between the tiles should be fine.
The carpet installers will make the carpet look good against the tile.

If you leave just the right amount of space for the carpet to fit, it
will work fine until you install new carpet, which will invariably be
different. Also, leaving a big space just makes a place for dirt to
collect.

--
Steve Bell
New Life Home Improvement
Arlington, TX