Using Chimney Cap to cover your Multi-Flue Chimney is a great way to beautify your home, while bringing organization to your roof as well as driving up the value of your home!  With so many different sizes and styles of chimneys, you need to be sure that the Chimney Cap you purchase is the right size and fit for your chimney.  Here are some basic rules that you should follow when measuring your chimney:

• Size:  You will want to choose a Chimney Cap size that is larger than the dimensions of all the flues (Diagram A, B) but smaller than the overall chimney dimensions (Diagram C, D)
• Note:  There will be a range of sizes available that will accommodate your chimney.  You can opt for a larger chimney cap so more of the chimney is protected, or if you need to keep costs down, you can choose a chimney cap size that just exceeds your flue dimensions.

• Screen Height:  You will need a chimney cap that has a screen height is 5" taller than your tallest flue (Diagram E, F).  This will ensure that they chimney will draft properly.

• Screen Mesh:  There are two types of screen mesh; 3/4" (which is the standard) and 5/8".  The 5/8" is designed to meet specific spark arrestor codes for particular communities.
• Note:  A screen mesh will serve a couple of different functions:
• It will help keep rodents and birds from entering into the chimney while still allowing the chimney to exhaust properly.
• It serves as a spark arrestor, not allowing sparks and embers to escape from the chimney and into the environment where it could cause a fire.
• Many localities - primarily California, but also in other areas around the nation - have spark arrestor codes that call for 1/2" spark arrestors.
• The California state building code calls for such spark arrestors on all new construction. Other California codes call for it in "wooded areas" or "within 200 feet of wooded areas" and when it comes time to sell your home, you can also bet the inspector will require you to update your chimney cap to comply with the spark arrestor codes.
• Be sure to check your local building codes to see what mesh thickness is required in your area.
  

• Lid Style:  A Chimney Cap can come in two lid styles: Flat and Hip/Ridge.  The Flat lid is standard and does not add any additional cost.  The Hip/Ridge lid is a major upgrade that adds improved ascetics and functionality (see photo).  The lid will overhang the screen by 5" or 2 1/2" on each side.  If purchasing a Hip/Ridge lid, you should expect an extra 10 days for processing.
• Note:  If the dimensions you have chosen are square (i.e. 13x13) the Hip/Ridge lid will come to a point at the top rather than feature a ridge.  Also, most of the Hip/Ridge lids feature a pitch of 8/12.

With every chimney being different, it's hard to try to find the one that fits yours.  However, if you know what your looking for when measuring and are willing to pay a little bit of money, a chimney cap will be an excellent investment that will give you returns for many, many years to come!  As always, if you have any further questions, we're always here to help!