Installing a Prefab Fireplace

What You'll Need
New prefab fireplace with flue and instillation kit
Measuring tape
Quick setting concrete
Hand wood saw
Plywood for a face plate
Aluminum sheet or tiles for the hearth
Tile adhesive

Factory built, a prefab fireplace can be quickly and easily installed by anyone with basic home improvement skills and the right tools. Most prefab fireplaces are made of metal and come prepared with a chimney system as well as the firebox. They are low maintenance and easy to use, with far less mess and work required than a traditional fireplace. Here is a basic outline to installing a prefab fireplace: 

If you are installing your prefab into an existing fireplace, there will be little work to do. It should fit inside the fireplace and the flue will go up the chimney. 

 Step 1 – Measure the Space

Measure where your fireplace will go to make sure it fits, and that there are no ceiling joists directly above it, where the flue/chimney will go. The chimney must not be located within 2 inches of a wooden joist. Measure how high the flue will be and decide if you need one or more flue sections extra, or if you have enough.

Step 2 – Build a Solid Foundation

A concrete foundation must be built to the depth of the house. Measure and cut out the floor to the same size pus 2 inches all round, as the base foundation will be. Build a plywood box form around the edges of the hole to the existing house foundation. Pour concrete to fill the hole flush to the floor level. Allow the concrete to cure for 24 hours.

If your house floor is more that 2 feet above the ground, use house bricks to build up to floor level, then pour a foundation slab for the fireplace. 

Step 3 – Cut the Flue Hole

Cut a round hole in the ceiling where the flue will fit. It must be bigger than the flue's circumference to fit the metal flue ring. Get up on the roof and make a hole where the flue will exit. 

Step 4 – Place the Firebox into Position

Slide the fireplace into position, then put together the flue and attach it. Install the roof flashing and closure and then top off the flue with the cap that will have come with the set. The flashing will make sure that the instillation is waterproof. 

Step 5 –Make a Face Plate

Ignore this step if you are not setting the new firebox into an existing fireplace.

You can choose to make a face plate for your fireplace with drywall or plywood. Make sure it does not touch the fireplace face frame. Butt it against the outer edges of the frame instead. 

Step 6 – Finishing the Hearth

You have two choices here, you could slide a piece of aluminum sheet under the fireplace to serve as a spark arrester. It should be it to the size of the hearth you require. The other choice is to lay tiles for the hearth. 

The complete system must be installed properly with a minimum clearance between the firebox and flue and any combustible materials including wood framing and insulation in the roof space or attic.