BHA HMC Standards for Brickwork and Chimney Repair
All brickwork repairs must meet professional masonry standards. Any deteriorated or spalled brick must be removed, replaced with Chicago brick, and tuckpointed (mortared) properly. No concrete repair of brickwork is acceptable. In less visible chimney areas, it is acceptable to replace deteriorated Chicago brick with a less porous brick that is more durable (i.e. Old Chicago Brick) of the correct size and close color blend match to Chicago brick.
Brick piers/ veneer at garage level: For a cavity under a pier, fill the cavity with appropriate masonry material. For deteriorated brick or mortar, remove and replace the Chicago brick, and properly tuckpoint the area.
It is strongly recommended that homeowners coat their brickwork with a water-repellent treatment (i.e. Chimneysaver) to reduce water intrusion and extend the life of the brick.
A City building permit are required for chimney repairs. Once the repairs are completed, BHA Homes Maintenance Committee will arrange for a GAF roof warranty representative to inspect the roof area around chimney work to ensure the repair work meets GAF Golden Pledge roof warranty requirements.
Newly repaired areas of brick – mortar joints should be struck to prevent moisture intrusion. This is critical on chimneys above the lowest roof line and other areas that may be subject to excessive moisture. The use of a water repellent is strongly recommended.
There must be no Old English Cut joints on chimneys above the lowest roof line. [an “Old English Cut” mortar joint results from a technique where the mason cuts away protruding mortar from the front of the wall/structure without striking the joint to seal the outside surface of the mortar to the brick].
There must be no wheel raked joints on chimneys above the lowest roof line [a wheel raked joint is where the mortar has been cut back a certain distance - approx. 1/4” to 3/8” - from the front of the brick], as this type of joint exposes the front of the bricks to moisture infiltration, an easy path for water penetration into the wall/structure.
Moisture penetration is a big concern when porous brick, such as Chicago brick, has been used. It is important to prevent or minimize moisture infiltration to extend the lifespan of the brick and mortar by using proper masonry techniques and applying water repellant treatment (i.e. Chimneysaver).
NOTE: An ACC application is required for chimney crown work. Both chimney crown styles described below and shown in in this section meet City code and do not require a building permit.
Remove any “dummy” tiles [terra cotta clay flue placed into the concrete crown at the top of the chimney and filled with masonry material to aesthetically balance the look of the chimney] and close the crown area to reduce the amount of moisture that enters the crown at the time of crown replacement (no resetting “dummy” flues into newly poured replacement crowns is allowed). On existing dummy tiles, be sure they are sealed with clear silicone or a better product [joint around the circumference of the tile and top area and shape to wash water off].
Chimney crowns must be natural concrete in color, not white. The crown should not be flat, but angled to shed water, with a minimum thickness (height) of 3.5 inches. An expansion joint, minimum 1/16 inch, should be placed around any flue or projection out of the top of the chimney chase to allow for expansion of the flue, minimizing damage to the flue and crown. This gap around each flue should be sealed with an appropriate material (100% silicone).
An overhanging crown is also permitted. In addition to the requirements above, it must have a 2- to 4-inch overhang and a gap or kerf on the underside of the overhang, at least 1/8 inch thick and 1 inch away from the vertical plane of the brick chase to create a water break. The main purpose for the overhang is to minimize moisture infiltration into the brick. Without the gap or kerf, the overhang is much less effective.