I've had several people inquiring about how to salvage materials from a construction site, so that is what this post is about. Before I go into the actual how-to, I think that there are a few things you need to realize about the environment that you will be entering. The world of construction workers is much different than what most of society has ever experienced. It is very dangerous and you must know the proper rituals to get through. Also, I am in no way guaranteeing that this will work; this is just my advice. For some companies and some regions of the country, they will never give you scraps.
Number one, the superintendent is the absolute ruler of this world and they look at it absolutely from that perspective. They rule the job sites with an iron fist; it is not a democracy. Once you piss one off, you will most likely never have his cooperation again. The worst thing you can do is march out into their domain, with no regard for their rule and try to start making off with stuff. I say 'try' also because you won't get far. You must acknowledge the superintendent's authority. Go straight to the job trailer and ask for him. Many job site even post signs (we do) saying that all visitors must report to the office first. If you don't see an office trailer, ask the closest worker you can find without going out onto the site. Wait at the gate if you have to. Do NOT enter the site unless you have direct permission. This is for your safety as well as to keep from pissing everybody off. If you get to speak with the superintendent, tell him specifically what you are looking for (scrap lumber, rebar etc.)and what you want it for (you're trying to build a little shed or greenhouse etc) but don't go into some long, drawn out spiel. Keep it specific and to the point. They don't have a lot of time. Also, I have found it helpful if you use the correct terminology. Tell them you are looking for 'drop' or 'dunnage', not just scrap wood. 'Drop' can be any material (wood, metal, whatever) left over after they have cut off what they need. It's what drops on the ground. Get it? Dunnage is the 2x's and 4x's that heavy materials are shipped on. It's usually oak, poplar, hickory or pine anywhere from 4 to 8 feet long. It makes good, free firewood. But whatever you are looking for just ask as specifically as you can. I always say to tell them what your project is also because if you get a friendly bunch they might suggest other materials that would also work if they don't have what you are looking for. Construction workers are very creative and resourceful.
Say 'yes sir' and 'no sir' and do exactly as they instruct IF they allow you onto the site. If they tell you to wear a hard hat, DO IT and do not take it off while out on the site. There are so many rules and laws now, about what even we can do, that the safety regulations are a major concern. The superintendents can actually be personally sued for accidents on their jobsites so they don't fool around. This is why many companies won't even allow people to take their trash. If you get hurt on a site they are in some major doo-doo. And above all, if they tell you no and not to go out onto the site, do not under any circumstances think you can get around them and go out there anyway. These men are not people to mess with. They will not react kindly. Many of them have well earned their reputations for being coarse, misbegotten thugs. But it's not because they like being mean, for the most part, it's because the world of construction is very harsh and you sometimes don't get a second chance.
Which brings me to the second subject, safety. If they allow you out there, realize what you are getting yourself into. Even if it is just a house site you can still get stuff dropped on you and there is often heavy machinery running. Watch what is going on around you constantly. If you hear a backup alarm on a machine, look for it! Do not walk under any scaffolding, ladders or structure if people are working up there. You most likely will have someone with you (they will not let you just run amok) so they will guide you. Just do what they say and watch yourself. Jobsites, especially commercial ones are very dangerous. Many men are killed every year from falls, stuff falling on them, electrocution, soil cave-ins and such. If you see Danger or Caution tape up, do not cross it. The photo above was taken on one of my last jobs. Those are concrete tilt-up panels that make those walls. We pour them on the ground and stand them up basically. They weigh between 35 and 45 tons apiece and are only held up for a time with those two little sticks of iron. Realize and respect the environment where you are going. If one of these panels falls on a man, they scrap him up with a shovel. And yes, it happens.
Lastly, dress appropriately, especially you women. While it is true that the men are certainly more generous to women, don't go out there dressed like you just got off the street corner. They might like to see your boobs hanging out but they are definitely not going to have any respect for you and be inclined to help you. That is also a good way to get one of men hurt. You distract one for a minute with your cleavage (yeah, and they are going to look) and that might be enough time for him to cut something off he needs. Act responsibly. Wear boots if you have them or at least sturdy tennis shoes. Men, same for you. Bring a pair of gloves. Act like you have picked up a shovel or hammer before. Be courteous and appreciative. Remember, they are doing YOU a favor. And don't be too greedy. Don't go out there asking for everything you lay eyes on.
I know with my company, we try to reuse as much of our waste as we can. We distribute it amongst ourselves, we try to give it away to others if none of our guys want it but not all companies do this. However, I always say, it never hurts to ask and I am not trying to discourage you with this post. Many companies are glad and encouraged to give away leftover materials these days. Also, keep in mind that even if some materials are left over, the owner always has first choice. They often elect to keep materials. I mean, they have paid for them. Even still, you can often find lumber, plywood, steel, rebar, concrete block, sometimes glass, insulation (all types), doors (although usually commercial type) door hardware, toilets, sinks, faucets, plastic, you name it really. Many times you can even get plants and shrubbery. If you still have questions, please let me know or if I did not make something entirely clear. I'm happy to answer any questions.