Convert attic to usable space

[PALefty]

Let me reinforce the above cautions... The bottom span on manufactured trusses is NOT engineered to support much weight, but only to keep the upper cantilevers from spreading where they meet the top of the perimeter walls. Intermediate stringers may be arranged to allow additional bearing on interior load walls, but this does little to increase the load bearing capacity of the BOTTOM span (the "joist"). Remember that, if you deck the bottom spans, they will ALREADY be supporting the weight of both the decking AND the ceiling drywall, and this is before you even start putting anything up there. I'm not saying that your ceiling will collapse (although it might), but any downward bowing of the trusses from the unanticipated additional weight will give your drywall joints cause to crack, and also might trigger nailhead pops, or other undesirable results. Be careful, and spread out any load you put up there toward the edges, and toward any internal bearing walls.

And just a word about insulation. DON'T compress it. It is not the insulating material, but the airspace within it that does the insulating. Compression forces the air out.

So do you favor building up the walls so that they will take the load instead of the joist/truss?

Yeah, I was pretty sure that compressing the insulation was bad...

[PALefty]

PALefty, if your area gets below freezing or very hot, you should keep in mind that an attic may not be the best storage location for most objects. You'll want to minimize air loss from house into attic (warm moist air hitting cold attic air in winter -> condensation). And to ensure really good attic ventilation, to avoid this humidity build up in winter and also overheating in summer.

BTW, it's handy to have your location listed in your user profile, so people don't make suggestions appropriate to Alaska when you live in Arizona.

Yes, I don't intend on putting anything important up there. Many different temps here in Eastern PA (PA_Lefty).