Jake wheeled his heavy flatbed cart to a stop in the lumber section, and for a few seconds remained perfectly still.  He was pretty sure that the inside of the building was safe, but pretty sure will get you killed if you aren't careful.  He listened for any movement or moaning.  He coughed twice, and listened again but heard nothing.  Reasonably satisfied, he started walking up and down the lumber isle looking for what he could use.<br/><br/>Although Jake's career specialty was electronics, a lot of his schoolwork was in general engineering so he had a decent idea of how to build a rigid structure.  Originally he wanted to get 4x4 posts and use them as the primary barricade but when he took a better look at them he realized they were going to be too much of a pain.  While he hoped that they could find enough power drills and batters to hang the wood, they would have to use hand saws to cut it up.  He'd done it before once on a project at his dad's shop, and realized that hand sawing all those huge beams would keep him up half the night.<br/><br/>Jake turned instead to the copious piles of 2x4's and plywood sheeting.  He figured if he slapped some plywood across the door, and then reinforced it with rotating layers of 2x4's and plywood, it should produce a very strong laminate structure.  Plus, none of it would be too hard to cut or drill through, and if they had to they could always resort to nails.<br/><br/>Moving quickly, Jake piled up a dozen or so sheets of 3/4", subfloor grade plywood and then as many 2x4's as he could fit and still operate the cart.  He started pushing and it took him a while to get the heavy cart going, but after 5 minutes of grunting and heaving, he pulled up next to Marcus at the front door.<br/><br/>"Hey man, thanks for keeping watch.  Can you give me a hand unloading this?"