Build a Fireplace, Brick by Brick

while photographing the article build a fireplace brick by brick I brought the video team along to capture the process traditionally a Rumford is known as a tall shallow fireplace designed to reflect heat in this execution mason mike Mahaffey maintains the aesthetic but adds depth the firebox to be code and curves the back wall inward to maximize heat reflection although it will eventually be surrounded by 8 inches of solid masonry the focus here will be on the layout and erection of the visible interior fire brick layer of the firebox when we arrived on site the guys were just beginning to mix concrete for the 12 inch thick base slab that will support the firebox they decided to mix their own rather than hire a truck due to obstructed access and the relatively small amount needed about a yard and a half while the crew methodically mixes two bags at a time mike marks out the fill line for the top of the slab then they fill the form spread the concrete evenly and set the rebar Mahaffey likes to set the rebar after the poor because it's easy to position and keep in the top half of the slab without having it compressed to the bottom once positioned he taps it beneath the surface and trials it smooth then as the concrete begins to set up he trials notches into the surface for bonding with the next layer creating a keyway of sorts then they leave the slab to set overnight the next day brought snow and a whole lot of cold so the guys tented in the work area in an attempt to keep the temperature above 50 degrees the minimum working temperature of the mortar they'll be using once tented it was time to lay out the base of the firebox on the slab he begins by snapping a chalk line to mark the front face then he draws a centerline and measures out 21 inches in each direction to mark the 42 inch opening then he draws a line along the back to establish the 20 inch depth to lay bricks Mahaffey works from the centerline out extending edges beyond the layout lines to integrate with the eight inches of solid masonry that will complete the firebox because the bond is outside the combustion chamber Mahaffey uses a standard type s mortar to bomb the fire brick to the slab he positions the front of the first brick along the read layout line that denotes the front of the firebox and establishes the height using a string line that represents the finished height of the base then he follows up with a level to get each brick set perfectly before moving on between bricks he switches to fire resistant mortar because the joints will be exposed to combustion it has a fire rating up to 2500 degrees they mix the fire resistant order in a five-gallon bucket to keep batches manageable and use a mixing paddle to completely eliminate lumps as they mix to achieve the smooth consistency of a thick paste like thinset for setting tiles as he fills in Mohave always works from the center line out to maintain a consistent stagger between rows he seats bricks by tapping them with the handle of his trowel or with a Mason's hammer the tapping is light just enough to get the position exact then he cleans any squeeze out from between joints and moves on to the next brick he fills in until he reaches the 20 inch depth and then switches to standard brick to extend the base by two rows beyond the combustion chamber again to support eight inches of solid masonry that will be built up around the fire brick to complete the firebox with the base in place a half he can move on to the walls to mark the inside corners of the 42 inch opening he measures out from the center line 21 inches in each direction and makes a mark then he measures back 20 inches the code depth of a firebox to establish the back wall for the angled walls he wants to have two and a half bricks visible so he dry lays them lining the front edge with the front mark as he pivots the row until it meets the back then he draws a line to transfer the angle to the other side he simply measures from the center line to the corner and transfers that measurement in the other direction then he connects the two marks with a straight edge and draws a line then he's ready to lay brick so I'm gonna start with the center brick in the back so that everything lines out off that center line so when you're looking at it although all the lines match up for the space between bricks he aims for joints about 1/16 of an inch thick all around refractory mortar can stain bricks so he tries to be as neat as possible to avoid a lengthy cleanup to minimize squeeze out he butters the mortar on only slightly thicker than the joint size he wants and bevels the edges to keep excess mortar away from the face as he lays the first row of the back wall he's careful to maintain the same bond pattern from the hearth on the side angled walls he works from the front edge back to help keep the front of the wall in line with the front edge of the hearth the bricks that butt into the back are pre-cut to a 45 degree angle and trimmed to fit with a brick hammer before buttering and installation as each course is laid he uses a straight edge to make sure all the bricks are level and in-plane and uses the handle of his trowel to tap any straight bricks into position as he built up the outer angled walls he also checks level side-to-side to ensure the walls are raised evenly and in-plane with a back wall some of the bricks that buttoned the back wall are pretty small as the walls get higher they'll get even smaller buttering mortar on small bricks can be messy and a lot of it may get scraped off as he sets the brick so he butters the gap the brick goes into so that joints aren't starved to mortar once he has to complete rows he takes a few minutes to check his joints cleaning up excess and filling and striking joints as needed so there are no voids then he drops plumb lines to keep the front edges of the side walls on track and secures them with line pins then he turns his attention to a fresh air intake vent that he lays out centered in the back of the firebox where he cuts bricks to encapsulate the vent so he can continue the same bond pattern seamlessly for the next several rows he repeats the process butter fit trim level and clean until it completes the sixth row now it's time to begin to arc the back wall inward the idea is for the back wall to arc inward to meet the back edge of the damper to do this bricks are back buttered heavy to the back edge which raises the back edge this prevents a whole lot of squeeze out on the face of the joint which he wants to keep consistent with the rest at 1/16 of an inch the side walls continue to be raised plumb without a pitch with the angle pieces fitted and trimmed to match the angle of the back wall for the arc rather than doing a mathematical equation a half he does it by eye arcing in a little at a time and then checking with a level to see how he's doing he wants to avoid arcing in too much too early which would result in the arc reaching the depth of the damper prematurely instead he works row by row inching his way forward if he has to increase the arc he'd rather do it in the upper few rows which will not be visible to the eye once he's reached the height the lintel is set and refractory mortar and align flush with the front edge of the firebox opening because the lintel will expand and contract at a different rate than brick all scrap of foam is inserted to prevent the lintel bricks from bonding with the bricks below next he beds the damper and refractory mortar and lays the final row of brick on the face then they continued to fill in around the firebox before giving a good acid wash [Music]

Channel: Fine Homebuilding

Views: 240,176

Keywords: Howto, Fireplace, Mason

Id: B9lQV-K-Okc

Length: 8min 3sec (483 seconds)

Published: Thu Aug 29 2019