Microlam headers are one of the newest technological innovations in recent history. They are basically a manufactured composite wood product, made up of many layers sandwiched together to create a beam that is "relatively" lightweight and incredibly strong. In many cases they have replaced steel I-beams in home improvements, and that's good for the contractors and homeowners for several reasons.
1) The typical microlam header is usually in stock, can be cut to length on site, and is available in depths from somewhere in the range of 9-16". This makes for immediate availability, and signficant decreased costs over special ordered, manufactured steel I-beams.
2) Steel I-beams are quite heavy and typically need 2 or 3 people and maybe pump jacks to get it into proper position. I picked up an 11 foot x 11 7/8" deep microlam header yesterday, (for only $50) lifted it myself, took it home on the roof of my car, and I will be able to liit into place singlehandledly. Well, I'll cheat..with a 2x4 scrap nailed on one end of the wall..and I will put one end on there, then lift the other all the way up on the top of the wall, then lift the first side into place.
3) Steel cannot be screwed into, so creative techniques have to be used to make a "nailing surface" for sheathing that will cover the beam, whereas microlam is a wood product and can be screwed into directly, making it easy to cover with sheetrock or other building materials.
This weekend is "wall ripout" time..the wall between the smaller den with fireplace and the very large living room with the fountain and **** woman statue with the nice boobs are going to be one continuous room. The microlam is sitting in my garage, and all I need is a dozen 2x4 studs to support each side of the ceiling while I rip out the existing wall, and install the microlam, probably using a car jack and a 2x4 to get it really firmly into place. The tricky part is not to allow settling or to over hoist it with the jack so that the sheetrock doesn't crack. There's an art to it and the skills really only come with experience. This is about my 6th beam/wall replacement so I think I got the "touch"...(famous last words).
I will take some before and after pictures of the project. The floor drops in the living room, which means there will be a long step dividing the two rooms, about 4 inches high. I "could" raise the entire living room floor with "creeper studs" but I'm not sure that it's worth the trouble...
Example of microlam header in place (new construction)