Finally got my brick corbel right on the third try

Last week I was working on a chimney rebuild in Springfield and the plans called for a 6-inch corbel. My first two tries looked okay from the ground, but up close the line was wavy. I went back to my old teacher's advice about marking every course with a story pole. Spent an extra hour setting up, but the third course went in perfect and straight. It's a small thing, but it felt good to nail it. Anyone else have a trick for keeping corbels true on taller work?

4 comments

4 Comments

ross.christopher2mo ago

Wait, a 6-inch corbel? That's a big jump per course. Most codes limit you to a third of the brick depth. A full 6 inches out would be over 2 inches per course on standard brick, which is asking for trouble. You sure the plan didn't mean a 6-inch total projection over several courses? For tall work, I mark the full profile on the wall with chalk first. Story pole is good, but you need the full angle laid out.

troychen2mo ago

Yeah, it's like when people skip steps in a recipe and wonder why it fell apart.

henry_murray2mo ago

So what's the actual total projection then?

abby_morgan181mo ago

Ross, I think you might be mixing up the brick depth with the corbel projection. Standard brick is usually about 3 5/8 inches deep, so a 1/3 projection per course would be around 1.2 inches, not the 2 inches you mentioned. A 6 inch total projection over 5 or 6 courses works out to about 1 inch per course, which is totally normal for a chimney cap or a decorative detail. I've done plenty of 6 inch corbels that way and never had an issue with code. The story pole trick is solid, but I also like snapping a level chalk line for each course as I go just to double check.