Worker on a ladder at the gutter line of a Long Island house in autumn

Alec's Construction repairs chimneys in Commack, Suffolk County — crowns, caps, repointing, spalled brick and the roofline flashing — working out of the yard in East Patchogue.

What Chimneys Do Wrong in Commack

Larger 1960s to 1980s colonials with tall exterior chimneys on the gable end. Tall exterior chimneys stay cold, draft poorly on a mild day, and show their repointing needs on the windward face long before the rest.

Flashing Before Masonry

If there is a stain on a ceiling anywhere near the chimney, the flashing is the first suspect and the masonry is the second. Chimney flashing is a two-part detail: step flashing woven in with the shingle courses, and counterflashing let into a cut in the mortar joint and lapped over the steps so water cannot get behind it.

What is on a great many Long Island chimneys instead is roof cement, troweled over the joint by somebody who was up there for a different reason. Roof cement is brittle within a few winters, it cracks, and it hides the failure while the water keeps going in. It also has to be chipped off before a proper repair can be made, which makes the eventual job larger.

Failed step flashing and old roof cement where a brick chimney meets the shingles

The Crown and the Cap Are Two Different Things

The crown is the sloped surface on the very top of the chimney, covering the brickwork around the flue tiles, and it is what keeps water out of the masonry. On a lot of houses here it is a thin skim of mortar troweled over the brick — never the right material, cracked within a decade. A proper crown is cast concrete, reinforced, sloped, with an overhang and a drip edge and a bond break at the flue tile.

The cap sits above the crown over the flue opening, and it keeps rain, snow, debris and animals out of the flue itself. It should be stainless, not galvanised: galvanised caps rust, streak the masonry below and end up in the yard. A blocked flue on a gas or oil appliance is a carbon monoxide problem, which makes the cap a safety item rather than only a maintenance one.

Repointing, and the Mortar That Matters

Failed, recessed or missing mortar joints get cut out to depth and repointed. On older chimneys the mortar has to be compatible with the existing masonry — a mortar that is harder than the brick will not let the wall move, and the brick takes the damage instead. That is a real decision, not a bag choice, and it is worth asking about.

Spalled brick gets replaced. Coating it or repointing around it leaves the failure in the wall.

Permits and Departments in Commack

Commack straddles the Town of Huntington and the Town of Smithtown, and the two do not file the same way. Huntington requires plans sealed by a licensed architect or professional engineer for alterations over ten thousand dollars; Smithtown does not have the same threshold. Repointing, crown and flashing repairs are generally maintenance rather than permitted alterations, but rebuilding a chimney above or below the roof line is a different scope, and we confirm with the department rather than assume.

Book It Before the First Fire

Masonry wants temperatures above freezing to cure, so chimney repointing and crown work are autumn jobs on Long Island and the calendar fills from September. Flashing, caps and sheet-metal work can be done later in the cold.

Free walkthrough in Commack. Alex goes up, photographs the crown, the cap, the joints and the flashing, and you get the photos whether or not you hire us.

Frequently Asked Questions

Why does my Commack fireplace smoke on windy days?

Usually downdraft on a tall exterior chimney. The big 1960s to 1980s colonials here have tall stacks on the gable end, which stay cold, draft poorly on a mild day and are exposed to wind blowing straight down them. A cap with a properly overhanging lid breaks that up and often solves it. If it smokes on every fire regardless of weather, the cause is more likely flue sizing, height above the ridge, a blockage, or a house too tight to feed the fire air.

What is the first thing to check on a chimney?

The flashing, if there is any sign of a stain on a ceiling near the chimney. Chimney flashing leaks are far more common than chimney masonry leaks, and roof cement smeared over old step flashing — which is what is on a great many Long Island chimneys — is brittle within a few winters. Proper step flashing with counterflashing let into a mortar joint is the real repair.

Why is my chimney brick flaking?

That is spalling: the brick absorbs water, the water freezes and expands, and it pushes the face of the brick off. Long Island gets a lot of these cycles because the winter temperature keeps crossing freezing rather than staying below it. The water usually comes from a cracked crown, failed mortar joints or an open flue, and fixing those stops it progressing.

Do I need the chimney swept as well?

Sweeping and inspection are a chimney sweep's work and they are worth booking before the first fire of the season — a build-up of creosote in a wood-burning flue is a fire risk and a blockage in any flue is a carbon monoxide risk. Our work is the structure: the masonry, the crown, the cap and the flashing. The two jobs sit alongside each other.

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Work With Alec's Construction

This guide is written by the crew that does the work. See Alec's Chimney Repair service — repointing, crowns, caps and roofline flashing. One crew start to finish, free walkthrough and a written estimate inside 48 hours.

Booking the cold months now: we also handle Roofing and Seamless Gutters.

Get a Free Estimate from Alec's Construction

Working across Suffolk County since 2018, one crew from start to finish. We come out, look at the actual job, and put a written number in your hand — no pressure, no obligation.

Or call (631) 312-7441

No cost, no obligation. We reply the same day.