What Cement Do You Need to Build a Chimney Cap?

Chimney Cap Functions

• A chimney cap protects the inside of your chimney and flue from invasion by curious wildlife, nesting birds and most insects. This device also keeps the mortar crown portion of your chimney protected against damage from the elements. Without a chimney cap, burning embers from your fireplace can float out into the air and land on your rooftop or lawn. This presents a major fire hazard. Animals that fall into your chimney usually die and clog the stack. The last thing you want to have to do is fish a dead squirrel out of your flue.

Standard Chimney Caps

• Standard chimney caps do not usually use any concrete or cement as construction materials. According to Hearth.com, modern chimney caps use stainless steel, steel, copper or aluminum as main building components. These metals are much lighter than cement or concrete, which allows installation without the risk of added stress on the chimney's structural integrity. These metal devices also require less building intensive installation. The most popular method of installing modern chimney caps is screws along the base of the caps, which tighten against the inside of the chimney flues.

Draft Increasing Caps

• Draft increasing chimney caps raise the level of suction up chimneys or flue systems to remove more particulate matter and smoke from the homes below. These are useful in older fireplaces that might have diminished abilities to generate the updrafts necessary to send smoke up chimneys. These caps use similar metal building materials as standard modern caps, though these devices should not include any mechanical moving parts. Creosote and other particulate matter can quickly clog these mechanisms and render the caps relatively useless.

Custom Chimney Caps

• Custom chimney caps are necessary for chimneys that do not use prefabricated components and, therefore, new caps outside of normal manufacturer specifications. According to Hearth.com, custom chimney caps might use cement or stone as the main component in construction. It's easier to create custom caps from cement because creating metal chimney caps requires high-priced professional welding. Metal caps are available if you have no problem with spending the higher prices to create the devices.