choosing a chimney cap can be an overwhelming task but fortunately determining what size the chimney cap you need it's in as difficult as it seems grab a tape measure a pencil and paper and a ladder you will need to get up on your roof to physically inspect and measure your chimney I'm Melissa from Northland Express and in this video I'll be showing you how to determine which type flute you have and which measurements you need to take before you can choose a chimney cap let's start with talking about a single flute chimney with an extended flute this is going to be the most common chimney style it also is going to be the easiest cap to measure for you're simply going to measure the width and the length of your extended flute and make sure that you're measuring the outer diameter of your extended loop a single fluke apps often mount with pressure screws and a flue size range that it will mount to for example an 8 inch by 8 inch cap will make tip flus from six and a half inches to eight and a half inches in both widths and lengths now if you've got a single flue chimney but your extended flue on the top is going to be an oval or round flue you will need to use a tap mount style cap so if your flue is oval around make sure that you're measuring the total crown width and length and the width of the area surrounding the flute as well as the height of the flue if it's extended now if you've got a chimney that's a single flue chimney but the top of your flue doesn't extend out enough for a top mount cap or it's flush with the crown you'll want to use a flue mounted cap you'll just use it should be cap like it that's going to allow it to be held in place from the inside of the flue now if you do live in a very windy condition I recommend using a top mount bracket that's going to allow it to directly attach to the crown of your chimney rather than fitting inside it will be a much sturdier connection now we are measuring for this again outer width and length of your flue and you'll have the measurements that you need and finally the last style chimney you have may have would be a multi floor chimney and if you've got a multi flue chimney this is always going to require a top mounted chimney regardless of whether they're flus are extended or not the measurements that you'll need for this kind of chimney are the total prong width and length the length of the area surrounding the flue as well as the width and the height of the tallest Blues sticking out that is to make sure that it's at least five inches taller than Tallis flew as not to interrupt a draft of your chimney multi blue caps can be sized to fit just around the flues or to cover your entire chimney crown you can save on the caps cost by sizing it to the minimum amount needed to cover just the flute especially if you're going to be choosing an expensive material like copper but for the best looking cap and the added protection of covering your entire chimney crown most people do choose a full sized cap I hope you found this information helpful if you've got questions about measuring for a chimney cap or you need assistance choosing a chimney cap please give our experts a call at eight six six six six seven eight four five four they're always happy to help