The base of the fire pit must bear the weight and meet heating conditions. Simply placing a heat-resistant board on the terrace does not confirm both functions. First, check the appliance, substrate, and materials located under the visible surface.
Draw the complete cross-section
Mark the fire pit, support, insulation, and terrace surface. Add hidden layers, including any wood or heat-sensitive materials. An assessment ending at the top board does not describe the conditions of the rest of the structure.
Refractory bricks perform a specific function in the hot section. They do not independently confirm that the substrate beneath them will remain cool. The requirements of the specific device and the complete arrangement of layers and gaps must be checked.
Assess load-bearing capacity separately from insulation
Ceramic fibre board can provide proper insulation in a properly supported system. Selection includes pressure and method of load transfer. Do not use the declared board temperature as a value describing its load-bearing capacity.
HT Fireboard has a separate structure and described protective applications. It does not automatically replace the insulating board or support design. For each material, record the task, placement, and method of attachment.
Take water and handling into account
Check the drainage from the terrace and places where water may collect under the structure. Protection against heating does not solve the dampness of the base. The weight of the complete station also needs to be assessed for the actual support method.
Before execution, check the possibility of removing ash and setting aside hot equipment. The conditions for installing the fire pit should be confirmed without trial ignition on a random slab. Keep the drawing and documentation of the solution so that any later replacement of the surface or change of the device model does not occur without re-evaluating the base.