Chimney waterproofing for Gainesville brick, from local pros

Does the brick on your chimney turn dark in the rain and stay that way for hours? A breathable water repellent can slow that soaking, but only on masonry that's already sound. Our locally owned, family-run pros check and fix cracks, open joints, the crown and the flashing first, then try the repellent on a test patch before treating the whole chimney. That first inspection costs you nothing.

• Brick chimney waterproofing with a breathable repellent
• Chimney sealing only after cracks and joints are fixed
• Chimney water repellent tried on a test patch first
• Glass, plants and roofing protected from overspray
• Old glossy coatings checked before anything new goes on

1. Fix what a coating can't

   Cracks, open joints, the crown and flashing are repaired, since a repellent won't bridge gaps or failed metal.

   01

2. Clean, dry and cure

   Brick is cleaned and left to dry, and fresh repointing gets the 72 hours or more BIA Technical Note 6A calls for.

   02

3. Trial patch, then the full coat

   A test area shows how your brick takes it; then silane or siloxane goes on from the bottom up, wet on wet.

   03

4. Uncover, clean up, walk it

   Coverings come off windows, plants and roofing, and our pro shows you the treated chimney.

   04

Waterproofing is the last step, and some chimneys don't need it at all. These cases show where it fits.

Silane repellent

Small molecules that reach deep into dense masonry, and BIA Technical Note 6A notes alkaline surfaces help them react.

Siloxane repellent

Larger molecules that bond well with brick. TN 6A suggests a siloxane or a silane and siloxane blend for brickwork.

Water-based repellent

Application method, coverage and protection of nearby surfaces follow the selected product's current instructions.

Protective coverings

Plastic and tape over glass, painted trim, plants and asphalt roofing, which the data sheet says to shield.

1. 01

   Repairs before the coat

   Crack, joint, crown or flashing work comes first, priced separately.

2. 02

   Chimney size and height

   More brick uses more product and labor, and a tall chimney adds roof setup.

3. 03

   Old coatings

   A failing film-forming sealer may need attention before a penetrant can soak in.

4. 04

   How thirsty the brick is

   Porous brick drinks more product than dense brick, and the test patch shows which you have.

• Whether the brick darkens and soaks when wetted
• Cracks and open mortar joints to repair first
• The crown and flashing, where a repellent can't help
• White crust on the brick and the water behind it
• Painted, glazed or previously coated surfaces
• Windows, plants and roofing to cover during the work
• Repair and repellent prices on separate lines

• Dark, damp brick hours after a shower

  It's soaking up water. If the masonry is sound, a breathable repellent slows that; if not, repairs come first.

• White powder blooming on the brick

  Water is carrying salts out to the surface. The moisture source gets found before any coat goes on.

• A shiny coating that's peeling

  An old film-forming sealer trapped moisture. It's dealt with before a breathable product is used.

• Damp patches on the chimney indoors

  Moisture is finding its way through the brick. The entry point gets fixed, then a repellent can help the brick.

• Chimney Leak Repair Water coming in around the chimney found, stopped and dried out.
• Chimney Masonry Repair Brick and mortar on the chimney repaired with a matched mix.
• Chimney Flashing Repair Metal at the roofline re-formed so rain runs past the chimney.

• Chimney Crown RepairCracked concrete on the chimney top sealed, patched or poured again.

• Why your chimney brick is flaking, and what fixes it Water, the wrong mortar and coatings that seal moisture in are what peel the face off a Florida chimney's brick, and each one has its own fix.

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