These are construction terminologies I came across, is there somebody outthere who knows what their meaning is:

Slagger
Slabber
Tiler
Gangerman

I would trully appreciate to get their meaning.

Well, wouldn't a tiler be someone who lays tiles?

And I found slabber to mean this:

Slabber

\Slab"ber\, n. [See 1st Slab.] (Mach.)
(a) A saw for cutting slabs from logs.
(b) A slabbing machine.

(Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.)

It also means spittle, just so you know. :)