Caps & Masonry Repair

---

Chimneys perform several vital functions for the home, and their simple appearance misrepresents their complex construction and performance requirements. A chimney deteriorated by constant exposure to the weather can be a potential safety hazard. Weather-damaged lining systems, flue obstructions and loose masonry materials all present a threat to the home. Regular chimney maintenance is essential to prevent damage, deterioration and future high-cost chimney repairs.

Midcoast Chimney provides high quality cap installation, crown repair and chimney waterproofing

Chimney Caps Prevent Water Damage and Keep The Elements Out
Chimney caps, also called rain covers, are probably the most inexpensive preventive measure that a homeowner can employ to prevent water penetration and damage to the chimney. Chimney caps have long been recognized as an important chimney safety and damage prevention component. Underwriters Laboratories (UL) specifies that any chimney lining system that is to be listed to their test standard must include a chimney cap.

Chimneys have one or more large openings (flues) at the top that can collect rainwater and funnel it directly to the chimney interior. A commonly-sized flue has the potential to allow large amounts of rain or snow into the chimney during just one winter when freeze/thaw cycles are common.

Chimney caps also provide other benefits. A strong, well-designed cap will prevent birds and animals from entering and nesting in the chimney. Caps also function as spark arrestors, preventing sparks from landing on the roof or other nearby combustible material. Caps may be designed to cover a single flue, multiple flues, a large portion of the chimney or the entire chimney top. A full coverage chimney cap usually represents a larger initial investment. However, it is probably the best investment for long-term protection because of its ability to protect the entire chimney crown.

Repair or Replace a Damaged Chimney Crown
The chimney crown (also referred to as the chimney wash) is the top element of a masonry chimney. It covers and seals the top of the chimney from the flue liner to the chimney edge. The crown should provide a downward slope that will direct the water from the flue to the edge of the crown. The overhanging drip edge, by directing the run-off from the crown away from the chimney, helps prevent erosion of the brick and mortar in the chimney’s vertical surfaces.

Most masonry chimneys are built with an inadequate crown constructed from common mortar mix that will crack, chip, or deteriorate from weather exposure. A proper chimney crown should be constructed of a Portland cement-based mixture and cast or formed so it provides an overhang projecting beyond all sides of the chimney by a minimum of two inches. The flue liner tile should also project above the crown a minimum of two inches.

Waterproof Your Chimney
Most masonry materials are porous and will absorb large amounts of water. Common brick is like a sponge, absorbing water and wicking moisture to the chimney interior. Defective mortar joints or the use of improper mortar or brick can greatly increase the tendency to absorb and convey water to the interior of the masonry chimney. 

Several products have been developed specifically for use as waterproofing agents on masonry chimneys. These formulas are 100% vapor permeable, which means that they allow the chimney to breathe. Therefore, water that has penetrated and the vapors produced when the chimney dries out or the water vapors produced during use are allowed to escape, while the waterproofing agent prevents water from entering from the outside. These products usually have a five- to ten-year warranty. Paint or clear sealers should never be used as a waterproofing agent because they will trap water vapors and moisture inside the chimney causing further deterioration.