The short answer
Chimney waterproofing protects brick and mortar from water damage. It combines repairs to the crown, cap and flashing with a breathable water repellent applied to the masonry. If you see white staining on the brick, flaking brick, rust or water in the firebox, have the chimney checked before the next freeze-thaw season.
Brick and mortar look solid, but they absorb water. In Brooklyn, rain, wet snow and repeated freeze-thaw cycles push that water into the chimney. Over time it cracks the crown, loosens mortar joints, rusts the damper and stains the walls and ceilings around the chimney. Chimney waterproofing from GoldenFlue Chimney Services is meant to stop that damage where it starts. Our certified technicians first find out where water is getting in. Then they fix the parts a sealer can't fix, such as a cracked crown, a missing cap or failed flashing. Finally, they apply a vapor-permeable water repellent to the brick. That keeps rain out while still letting moisture inside the masonry dry out. We work with homeowners in Brooklyn and nearby cities on row houses, brownstones, detached homes and small multifamily buildings.
Signs you need it
Water damage in a chimney usually builds slowly, so the early signs are easy to miss. Most homeowners notice one or more of the problems below. A single sign doesn't always mean the chimney needs sealing, but each one is a reason to have it inspected. Once water gets into the masonry, every winter freeze widens the cracks it travels through.
- White, chalky staining on the outside brick (efflorescence), which shows that water is moving through the masonry and leaving salts behind
- Brick faces flaking, chipping or popping off, or bits of brick and mortar collecting in the firebox
- Water, damp ash or rust stains in the firebox or on the damper
- A musty or campfire smell that gets stronger after rain, which happens when moisture mixes with creosote
- Water stains or peeling paint on the ceiling or walls next to the chimney
- Mortar joints that are crumbling, recessed or easy to scrape out
- A cracked or crumbling chimney crown, or no chimney cap at all
What's included
Waterproofing is more than spraying a coating. A sealer applied over open cracks or bad flashing will not stop a leak. That's why each job starts with an assessment and includes the prep work the sealer needs in order to do its job. The scope is confirmed with you before any work begins.
- Inspection of the chimney exterior, crown, cap, flashing and the masonry joints you can see
- Interior check of the firebox, damper and smoke chamber for signs of water entry
- Camera inspection of the flue when water damage to the liner is suspected
- Cleaning of the brick surface so the repellent can soak in evenly
- Sealing of small crown cracks, or a recommendation for crown repair when cracks are too large to seal
- Check of the step and counter flashing where the chimney meets the roof, with flashing repairs quoted when needed
- Repointing recommendations for mortar joints that are too far gone to seal over
- Application of a breathable, vapor-permeable water repellent to the exposed masonry
- Chimney cap check or installation to keep rain, debris and animals out of the flue
- Photos of what we found and a written summary of the work done
How our crew works inside your home and on the roof
Inside, we lay drop cloths from the door to the fireplace and cover the hearth before touching anything. When the firebox or smoke chamber has to be cleaned so we can see the masonry, we use rotary brushes and run HEPA vacuums at the same time. That keeps soot and fine debris out of the room. If we need to look at the flue, we run a camera up from the firebox or down from the top. That lets us show you cracked tiles, gaps in the joints or water staining that can't be seen from below.
On the roof, we set up safe access before starting and protect the roofing around the chimney. We clean the brick, make any crown and flashing repairs, and give repairs time to cure before applying the repellent. The repellent goes on at low pressure so it soaks into the masonry instead of running off. We avoid applying it in rain or freezing weather, so a job may be scheduled around the forecast.
The standard we follow
We follow the NFPA 211 standard, which calls for chimneys, fireplaces and vents to be inspected once a year. Chimney professionals use three inspection levels. Level 1 applies when nothing about the system has changed. Level 2 applies when the system changes, for example a new appliance or a switch of fuel, or when the home is being sold. Level 3 applies when a hidden hazard can only be reached by opening part of the chimney or the building. Most waterproofing jobs start with a Level 1 or Level 2 inspection. We only recommend Level 3 if what we see points to damage hidden inside the walls.
If your building has converted, or plans to convert, its boiler from oil to gas, keep in mind that New York City requires the chimney to be evaluated as part of that work. A new liner is often needed, because gas exhaust produces acidic condensate that can corrode a masonry flue. We'll tell you if the liner should be addressed along with the waterproofing.
What affects the price
Every chimney is different, so we quote after we've seen yours. The main factors are:
- Chimney height, roof pitch and how hard the roof is to reach
- How many flues the chimney has, how big they are and what condition they're in
- The fuel the chimney serves, such as wood, gas or oil
- How much creosote, soot or debris has to be cleaned before inspection
- How much brick and mortar has to be sealed
- Whether a camera inspection is needed
- Repairs the sealer depends on, such as crown work, flashing, repointing or a new cap
How a visit works
When you call, we ask about the symptoms you've noticed and when they show up, such as during storms, after snow melts or all year. A technician then visits, inspects the chimney inside and out, and walks you through photos of what they found. You get a written scope that separates the repairs that must come first from the waterproofing itself. Once you approve it, we schedule the work for dry weather. Many homeowners book in late summer or early fall so the chimney is protected before freeze-thaw cycles begin. That timing also works for buildings that need their heating system running during New York City's heat season, which runs from October 1 through May 31.