A barbecue smoker, as opposed to a cold smoker or smokehouse, uses more heat and a shorter cooking time to cook meats and infuse them with a delicious smoky flavour. Unlike cold smokers, barbecue smokers can have the fire or heat source inside the smoker cavity, making them much easier to make than cold smokers. Using concrete blocks you can quickly build a sturdy, no-mortar barbecue smoker.
Lay a course of pavers flat on the ground, slightly larger than you plan to build the barbecue smoker. Around 4-by-4 feet is good for a medium-sized backyard set-up. You can also build your smoker on a preformed slab, in which case the initial course of pavers is unnecessary.
Lay a course of concrete blocks, holes facing upward, for the first row of the smoker walls. At the back wall of the first row, lay two blocks with the holes facing the side for ventilation. Lay another four rows on top, then on the fifth and sixth row, place two blocks on the left and right walls with the holes sideways. These holes are for shelf supports as well as ventilation.
Sit a firebrick flat at the bottom of each corner of the barbecue smoker. Place a metal grate onto the firebricks for building the fire on. Once you have a fire that is reduced to hot embers, insert pieces of threaded rod through the holes in the sideways blocks as shelf supports. You can either hang the meat you want to barbecue from the rods, or place a grill rack over the rod supports and place the meat onto the grill rack. Place a metal sheet over the top of the barbecue smoker to retain the heat.
Add sawdust or wood chips on top of the embers to make more smoke. The dripping fat and marinade from the meat will also help make smoke. Spread a layer of surface-bonding cement over the barbecue smoker if you want to make it a permanent fixture, otherwise it can be dismantled or built up as needed. If need by, use firebricks to cover the ventilation holes in the bottom of the smoker to control temperature. Place firebricks on top of the metal sheet cover to increase insulation if a longer smoking time is desired.
Always use caution when lighting a fire and keep children and pets away from the barbecue smoker while lit.