Spark Arrestor Installation

An arrestor has a single fire-safety job: catch the live embers a wood fire sends up the flue before they land burning on your roof or in dry brush. Hot, lightweight embers ride the draft straight to the top, and over a combustible roof or in a wildfire-prone area an escaping ember is a roof-fire or wildland-fire ignition source. We install and retrofit arrestor screens sized and built to hold those embers in reliably. Set it beside our chimney-cap service and the contrast is clean: a cap is the weather-and-animal lid keeping rain and wildlife out, while an arrestor is the ember screen keeping fire in. The two are often combined in one fitting, but their jobs face opposite directions — the cap protects the flue from the outside, the arrestor protects the outside from the flue.

Mesh sizing is the heart of this job — a real balancing act a cap never has to make. The openings must be small enough to stop an ember — no larger than 1/2 inch under NFPA 211 — yet open enough not to clog with soot and strangle the draft, which is why code also sets a 3/8-inch minimum. Too fine and it sooting shut, and the appliance smokes back into the room; too coarse and embers sail straight through. We size the mesh to the code range and to how the appliance actually burns, and we build the screen in stainless so it can't rust thin and fail open — a corroded arrestor is just a screen full of holes, arresting nothing.

A lot of this is retrofit work, not a new top. Plenty of chimneys already carry a perfectly good weather cap but no ember screen, or an old arrestor rusted through, torn, or sooted solid — so we add or replace the mesh on the existing fitting instead of reinventing the whole top. Where there's no top hardware at all, we set an arrestor integrated into a cap so you get ember containment and weather protection in one trip; but the arrestor function — the code-sized screen — is what this service is about, and we'll fit one to a cap you already own. Where the cap page is about sealing rain and animals out, this is about screening sparks in to a verified mesh size.

This service earns its keep most in the wildland-urban interface and around any home near trees or dry brush — places where one escaped ember is a genuine wildfire risk and a local burn code or insurer often makes a compliant arrestor mandatory. We confirm the local requirement, which can run stricter than the NFPA baseline, and document the installed mesh size so the screen is provably code-compliant for an inspection or insurance file. The same containment standard governs every project our crew leads, weighing heaviest in fire-prone markets: a confirmed mesh size, a stainless screen that won't rust open, and a fitting that stays put — so the embers your fire throws stay inside the flue where they belong.