From the Firebox to the Flue: The Hidden Workings of a Safe Chimney | Code Compliant Chimney Construction Baltimore

A Guide to Safe, Code-Compliant Construction.

Your chimney does more than just vent smoke — it protects your home from fire hazards, carbon monoxide, water damage, and more. Here’s a behind-the-scenes look at what makes a chimney safe, efficient, and built to last.

Chimney Anatomy

From the firebox to the cap, each part of your chimney has a job to do. A properly built chimney ensures smooth smoke flow, contains heat, and resists damage over time.

Smoke Chambers & Flue Design

Smooth Flow = Safe Chimney

Smoke chambers guide gases into the flue. Poor design here can cause smoke to linger or back up. We use angled or corbelled walls that meet strict codes to reduce turbulence and improve performance.

Chimney Height & Roof Pitch

Height Matters: Chimney Draft & Safety

Your chimney must rise a certain height above the roofline to create proper draft and prevent downdrafts. This diagram shows the minimum clearances required to meet building codes.

Chimney Crickets

Preventing Roof Leaks with Chimney Crickets

When your chimney is wide, a small roof structure called a cricket is required to divert water away. Without it, water can collect behind the chimney and cause serious leaks.

Gas Liner Sizing

Gas Appliances Need the Right Liner

Installing a gas insert? It needs the correct size flue liner to vent properly. Undersized liners cause carbon monoxide and damage, while oversized ones reduce efficiency.

Hearth Extension Requirements

Keeping the Fire Where It Belongs

Hearth extensions protect your floors from heat and embers. Depending on the size of your firebox, there are code-required dimensions your hearth must meet.

Whether you’re installing a new fireplace, repairing an old chimney, or just learning more as a homeowner—these diagrams show why it’s worth hiring pros who know their codes. At Benchmark Chimney Services, we take pride in building and maintaining chimneys the right way.