Essentially you will need some sort of substrate for the mat. Many on the interwebs speak of using fabric painter's tarp. However I had some foamboard in my basement that I wanted to try since the foam board was essentially regulation size for a nice game of MERCS. In the end it held up really well. I guess the tarp would be nice since it can be lightly folded up when not in use.. however the goal was spending as little as possible.
So here is what you need:
* aforementioned substrate of some kind (tarp, foam board, etc)
* caulk gun
* acrylic white painters caulk (2-5 tubes, depending on surface area) I just needed 2
* large, plastic, cheap, putty knife
Apply blobs of caulk to the substrate and make sure to cover every inch of it.
Next its time to add texture and there are lots of cool ways to do it - but my first attempt is with a crumpled up grocery bag. Take the bag and blot, blot blot everywhere.
Then take a break..... a lonnnnng break. It took a better part of 5-6 hours to dry. I essentially turned in for the night and started work on it the next evening.
The rest is easy... just blast it with some spray paint. This part was a lot of experimentation for me and I will likely take more time and thought into the colors but really with zero effort, I created a decent battle mat for next to nothing.
Anyone else have tips or ideas on battlemat making? A special thanks to the Wargame Consortium Youtube video on the subject they helped me a lot in getting ideas.
Sorry for the nasty basement shots and the lighting issues but this is where the wife puts me for the hobby :(