When building an outdoor barbecue or fireplace, it is important to use firebrick for your project. Constructed with high alumina content, firebricks are designed to withstand high temperature ranges and resist flaking during the cooling process. Ideally, firebrick should withstand hot temperatures between 2,800 degrees Fahrenheit and 4,000 F. Most firebricks have a special coating to prevent flaking and hazardous dust gases cast off by the firing process. Some are available in special designs and shapes for artistic projects. Check with your local brickyard for available styles.
To prolong the life of your barbecue, use refractory mortar instead of standard cement mortar. Unlike cement mortar, refractory mortar is specifically designed to be used in applications that will experience high temperatures and cooling down processes, such as those of fire pits, fireplaces and barbecues. It will not flake or erode away like standard mortar, therefore creating a safer joint between the firebricks that will block flames from escaping and potentially destroying surrounding areas. Refractory mortar is available at home improvement stores in premixed buckets and has the consistency of thick drywall putty. Refractory mortar also sets faster than standard mortar, cutting construction time in half and because of its quick set time of only a few seconds, you will not have to use as much mortar to create the joints. Unlike traditional mortar that requires you to spread a layer of mortar a half an inch thick and hold the brick in place until it begins to set, refractory mortar requires only a thin spread between one-sixteenth and one-eighth inch thick. Refractory mortar also is water-soluble, which makes cleanup an easy task, eliminating the need to be meticulously careful to avoid damaging surrounding areas.
Tips for Laying Firebricks
Lay firebricks on an even, flat surface, using concrete to form a supportive footer that will hold the weight of the brick and prevent cracking caused by shifts in ground levels. When laying firebrick, spray the brick with water 24 hours before beginning your project. This step prevents the brick from absorbing the water from your mortar, which can cause the mortar to set up too quickly, creating incorrect bonding, and causing cracking. However, if you are using refractory mortar, you do not need to do this step because this type of mortar is calcium-aluminate based and does not require water to cure. When constructing a barbecue, you might find you have to cut some brick to create special pieces for tricky corners and tight areas. You can use a masonry hammer, although a diamond-blade masonry saw makes quick work of brick cuts. When cutting firebrick, use special safety goggles to protect your eyes and gloves to prevent scrapes and cuts.