Chimney base shape? How to cut an arch in firebrick

Hi! I’ve seen a lot of pictures of chimneys where the base round of firebricks is trimmed to fit the arch so that it’s like “parabolic” for lack of a better term. Anyone have an easy way to cut that shape? Alternately I can shape the base with just mortar but I thought it would be better to cut the bricks to fit. Thanks!

Hi Hahvahd and welcome to the BrickWood forum.

Would you mind sharing in a reply a couple of the pictures you’ve seen? I think that would give our experts here a much better idea of what you have in mind.

For sure. Much easier that way - very hard to describe!



Many of us just used mortar to level the first chimney brick. I tried shaping bricks with a grinder, but was not happy with the results, so i just used the full brick. When you wrap with insulation and stucco, the effect goes away. I also added another chimney course on top - I just like the look better…:cowboy_hat_face:

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Gotcha. Yes, I agree with @AZDon on this. Some cover the front with veneer, others don’t. But if you use mortar to make a level base under the chimney brick, it will make little difference in your final build.

@hahvahd, not sure if this is still an open question but I simply cut the firebrick edge-wise at an angle that approximates the curve. I used a small Ryobi table top table saw with a masonry blade. Soaking the firebrick before cutting made it much easier to cut and greatly reduced the amount of dust. By doing it this way I was able to avoid the need for a curved cut while still getting the desired results.

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