The first step to building any fireplace is going to be to build the fireplace base. The best bases are almost always made out of some form of concrete. These steps are describing the creation of a 3 foot by 3 foot fireplace base, but you can also make adjustments and improvements as needed in order to create the preferred base for your fireplace.
-Floater Board ( 2x4 )
-Grate (2 ½ feet x 2 ½ feet)
-Self Threading Screws
Step #1: Measure Square
The first step in this process is going to be to create a square that is 3 feet by 3 feet. This generally should be measured in an area that is capable of being left untouched and alone for a few days. This is because you are going to be creating your concrete base here and then allowing for it to set. Later you will be able to move the base to any place that you like where your fireplace will be installed, but for now it needs to remain untouched and safe.
Step #2: Create a Box
Now you should create a box out of 2 x 4's encompassing your entire 3 foot by 3 foot square. You can use your circular saw in order to cut the boards to size and then you can screw them together with screws that are 2" in length and your screw gun.
Step #3: Lay Grate Down
Now you should lay your fireplace base grate down right into the square that you created. You should take care to make sure that it is even, seeing as you will not be able to change the position that it is in once the concrete has been poured into the foundation base for the fireplace.
Step #4: Mix Concrete
Now you can mix the concrete up in the wheelbarrow that you have purchased. The process involved here simply usually means stirring the prescribed amount of concrete form with water. It is vitally important that you take care to follow the instructions exactly in order to achieve the best possible results.
Step #5: Pour Concrete
Now you should pour your mixed concrete directly into the wooden square that you have created. You should be pouring directly on top, and the concrete that you pour should completely cover up the grate that you placed in the previous step.
Step #6: Level Concrete
Now you should level off the concrete, taking care to make sure that it is flush with the board tops using a floater board. Make saw movements in the concrete using this floater board until the concrete has been properly and fully leveled.
Step #7: Pull Square Boards
Allow for the concrete to dry overnight and then pull the square boards around the concrete, creating perfect corners and edges. Make sure that the base is allowed to dry for at least several more days, keeping it dry and warm as best as you possibly can.