The reflecting wall is a great structure to build in semi-permanent camps, and you can even build quick ones at overnight stopping points. These walls block some of the wind (when positioned correctly) and they reflect more of the heat of a fire back toward the user. When used in conjunction with a survival shelter, these walls can create a much more comfortable micro-climate by literally “fencing in” the heat. The wall can be any size or shape, and built from many different materials. Of course, bigger is better. And smoother walls reflect heat better than rough ones. But as long as you have something in place to reflect back lost heat, each stick you burn will make you feel warmer than you would feel without the wall.
Any wood can be used for a reflecting wall. If you’d like it to last, cut and stack green wood for your wall. The extra moisture of live wood will limit its flammability. If you’d like the wall to double as a firewood drying rack, you can build it from dead wood that is wet. Just pull out the sticks as they dry, throw them in the fire, and replace them with new wet pieces as you go. You could even use rotten wood to build your wall, if that’s all you have available. The bottom logs or poles that are closest to the fire will dry out and begin to burn first, unless you plaster them with mud, prop flat stones against them, or build the wall far enough away (about 1 yard) that it cannot burn. To build your wall, gather a pile of logs or poles, and drive two stout stakes into the ground. They should be closer together than the length of your shortest log. Set your thickest log on the ground, butted up against the two stakes, then drive in another pair of stakes to pin the log in place. If you plan a low reflecting wall, use stakes about a yard long and drive one foot into the ground. Go for longer stakes is you want a higher wall.
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Stone and Mud Walls
For semi-permanent camps (or when stone is your most abundant resource), build a stone wall to bounce back the heat of a fire which would normally be lost. The rocks can be laid “dry” (without any mortar), or you can use mud or clay as a mortar substitute. Mixing dead grass with the mud will add additional strength to the mortar. And if enough mud and grass were available, you could even build your reflecting wall entirely from mud mortar (also known today as “cob”). Make it wider at the base for stability, insert sticks here and there for internal support, smooth the surface for heat reflection, and don’t go too high all at once. Top heavy mud walls tend to flop over.
A Note on Safety
For any rocks you plan to use near a fire, make sure you get your rocks from a dry location. It’s also smart to test them in a campfire (while you’re at a distance) to make sure they don’t explode. NEVER use rocks you collected by a waterway (high rate of explosion). Ever built a fire reflecting wall? Please share your results by leaving a comment.