" -So it's the Buckley Rumford Fireplace company, right?"

" -That's right."

" -And we'll talk about the precast elements a little later, but the firebox is gorgeous."

" -Oh, John and Steve here are doing a great job with this herringbone fireplace. "

" -Yeah, that's not easy to do. Now first you lay them all down flat and do all the cuts, right?"

" -That's right. It makes it a lot easier to cut them all out. Well, here's a little bit on the floor over here where they haven't put in yet."

" -Yeah, the very top ones. So that's one of the critical things is you lay everything out down to the smallest pieces for the top"

" -and the only way you can do that is with the water saw, right?"

" -That's right."

" -Now tell us a little bit about the theory behind this type of fireplace. "

" -Well, Rumford Fireplaces are named for Count Rumford. The design is about 200 years old. And they're, as you can see, tall and shallow to reflect a lot of heat, and then this throat is the rounded curved part that the air comes in, the face of the fireplace and turns a quarter circle into the--through the throat."

" -Right. The throat is the transition piece between the firebox and the flue."

" -Right, and it's kind of like an airplane wing. You want to keep that air flowing in laminar fashion over there and that shoots it like a carburetor or a nozzle of a hose into the smoke chamber."

" -Yeah, and most fireplaces who don't have that design, a lot of the heat that's generated from the firewood is lost right up the chimney."

" -That's right. The Rumford, by keeping it streamline, we can make the throat maybe a third as small."

" -This is a nice brick, too. What type of brick are they using here?"

" -Well, this is Whittaker Grier brick."

" -Say it again."

" -Whittaker Grier. They make it in Alliance, Ohio. And it's a dry press brick rather than an extruded. So, it's a fire brick and it stands the heat very well."

" -So that means that rather than have the clay kind of in a vat and extruded through the form"

" -They press it."

" -They press it into forms."

" -That's right."

" -And can you use Portland cement when you're building a firebox?"

" -Well, you shouldn't because Portland cement degrades at about 600 or 800 degrees. And so it has a short life, and it can't stand the heat. This heat stop refractory mortar is a high temperature mortar and if you're using firebrick, you might as well use an equally high temperature mortar to put it together with."

" -Okay."

" -This is very versatile. We put the flues together with it. We can cast it into shapes, as well as lay the groundwork."

" -But what's the chemical difference between Portland cement and this..."

" -It uses a different kind of cement binder called aluminate, rather than Portland cement."

" -Okay. So this is probably the way of code requirements."

" -Yes. Some codes already require it, and the new ICC codes, which will be out in a year or two, will all require it."

" -Okay. I see he's doing away with the plumb lines at this point."

" -They're in his way I suppose now."

" -Yeah, yeah! And now we just have the last few courses to put together."

" -This is the top of the box here. It's 4 feet tall and that throat fits right on top of it."

" -Okay."

" -The critical part of finishing off the herringbone is to get it all perfectly flat along the very top, so that when we install the precast throat, we don't have to worry about it not fitting right. Now the base for the whole chimney is essentially a pored concrete pad, and the space underneath it, which is walled in the perimeter with concrete block, is then filled in with sand, then you've got all the rest of the shape, if you will, created out of solid half-blocks like this, and this more or less creates the form of the Rumford. "