Field Craft

[DropDeadFred]

I'm involved in building up a playing field from scratch and we are looking for ideas on what to use for building materials. We already have Hyperball and most likely will have a sticks field, mounds and a tractor tire field. One thing I've always wanted to do is to build a half demolished urban area. With structures that have been blown to pieces, walls that are half missing. I'm thinking about using a concrete and styrofoam mixture. What I'm really wondering is if anyone has any experience with building with concrete/styrofoam mix? What did you use as molds? How thick do would walls need to be to withstand regular play. How deep down in the ground do they need to extend? Rebar? Also if you all have any other helpful ideas for some unique and fun play fields, please do tell. Thank you.

[Grendel]

At the old Vanguard field in Columbia, SC we did built a few bunkers with Aircrete. Basically built some simple frames to support the bunker/wall shape, covered with burlap material and sprayed the surface with Aircrete. I would have like to do more but limited resources at the time and I was in the Navy back then and got transferred. It actually works well and holds up to paintball good as long as you have some thickness. We had erosion from weather and paintballs at the edges where the Aircrete is thin. Making plywood molds to cast bunker shapes (kind of like "Jersey Walls") was on the list to experiment with but I am sure would have worked even better. From my experience 2-3 inches minimum for Aircrete to hold up to weather and paintball. If I was to mold something I would model it off a Jersey Barrier but maybe scaled down a bit. Understand while Aircrete is lighter and a lot lighter then plane concrete any molded wall is going to be heavy. The first experiment was with making a fixed walls for a building and we sunk the poles of the frame about 2 ft. into the ground. After that the couple of bunkers we made were smaller tilted back walls about 4 ft. tall with triangular support frame off the back where the supports also acted as skids then the frames were covered in burlap and coated with 1-2 inches of aircrete.

Look for Road contractors they dispose of "Jersey Barriers/Walls" occasionally due to damage and sometimes you can get them for free if you can haul them off. If you go that route just be sure to make them safe for players to play around [exposed rebar is common]. They also make plastic ones that are meant to put water in to hold them down, they are also pretty good for bunker material.

We had pretty good luck offering up parts of Vanguard to regular players/teams to design and build specialty structures and bunkers on a dedicated area. Just be sure you approve the design, materials and construction. We had a player build a huge bunker that looked like and was to scale for a Sherman Tank that we could drag around with the tractor occasionally.

We also build a "Vietnam" Firebase with trench all the way around it, a tower in the middle (Basement, 1st floor, 2nd floor) that was missing parts as if it was being constructed or damaged. In addition we salvaged an actual scrapped Cessna 1120 body/winds that we painted Olive Green and had it crashed nose down. We took out all the windows and sealed up the doors so it was only a bunker/barricade.

Old telephone poles make a good start on building bridges over creaks and streams and can be pretty reasonable in cost. The tower I mentioned above the 4 main posts were old telephone poles sunk several feet in the ground to build off.

275 Gallon Water/Liquid Totes are ready made bunkers that you can weight down with water.

[BrickHaus]

Why not just build with real block? I think it's cheap enough.

I helped build an urban city at a local field. We simply poured a fake footing at grade ( 4 inches of concrete in a trough) then we laid half walls up. No core fill. No real structure to it, but it's held up better than I expected over the years. We get a hard freeze here too, so it surprises me even more.

I attached a webpage photo from the field showing the beautiful city I was part of building.

I liked the foam mix bunkers until they start to degrade. It seemS they crater out and you know they are foam pretty quickly.

[flyweightnate]

The one thing we have to watch out for is critters. If the bunker has voids, or a hollow shell, it gets filled with ants, red wasps, recluse or widow spiders, or worst, rattlesnakes. The hollow plastic jersey barriers are a nightmare for it. So just consider your local wildlife when you think about the shape of bunkers.

I wonder if you could find a building science tradeschool and let them train people with insulated concrete forms, or block walls, or whatever else they're trying out with the local kids, without worrying about disposal or longevity. Might be a win- win.

[cellophane]

Why not just build with real block? I think it's cheap enough.

I helped build an urban city at a local field. We simply poured a fake footing at grade ( 4 inches of concrete in a trough) then we laid half walls up. No core fill. No real structure to it, but it's held up better than I expected over the years. We get a hard freeze here too, so it surprises me even more.

The one thing we have to watch out for is critters. If the bunker has voids, or a hollow shell, it gets filled with ants, red wasps, recluse or widow spiders, or worst, rattlesnakes. The hollow plastic jersey barriers are a nightmare for it. So just consider your local wildlife when you think about the shape of bunkers.

I wonder if you could find a building science tradeschool and let them train people with insulated concrete forms, or block walls, or whatever else they're trying out with the local kids, without worrying about disposal or longevity. Might be a win- win.

CMU is cheap and easy to build with and will last forever. ICF could be good, but the foam will take a beating and might not stand up long-term unless it has a finish on it. For a 3ft to 4ftt wall I would go down at least one course for stability, but you can get away with less depending on the design of the bunker. Something like the attached image is about what you need. The intermediate bond beam probably isn't needed on anything less than 8ft tall. Over 8ft and you should probably have someone run calcs on it to make sure everything is kosher.

Contacting your local BAC or trade school as flyweightnate mentioned is a great idea. Here's the website for the BAC: https://bacweb.org/

I would also pay a lot of attention to the critters as mentioned above. I would be very, very, very unhappy if I slid into a bunker and landed near a snake or yellow jacket nest.

edit: Anything with old vehicles- make sure the glass is removed and all potential sharp edges are dealt with. Sheet metal cuts are nasty, and rusty sheet metal cuts are worse.

[Ratzo]

We have made a small speed ball field with oil drums I grab from my work. The sound is crazy when people are wailing away on the triggers.