An earlier photo that I posted got me going on this subject today. Lets talk about chimney crickets and how they pertain to home inspection. Do they matter?
First of all, we need to know what a chimney cricket is. Without spelling out the technical definition, lets make it easy. It is a small peaked roof built on the backside, or high side, of a chimney to direct water and debris away. When a cricket is installed on your chimney, debris will be less likely to build up behind the chimney and therefore will not deteriorate your roof material.
Lets take a look at a chimney cricket. Nevermind the shingle job over this cricket, we are only concerned with the chimney cricket here.
Now, if we disregard the shingles, we will see that water running down the main roof towards this chimney will be directed away as it approaches. A chimney cricket will help keep the back side of your chimney free of debris and water puddling or ponding. Picture this in early spring in a northern climate. Water trickling down the roof in the day time begins to freeeze as the temperatures drop. Now if that water freezes right behind the chimney, you may have an ice dam issue. By having the chimney cricket, the water will be directed around the chimney, rather than gathered up directly behind it.
Now, lets take a look at a chimney that does not have a cricket installed. You will notice a small amount of debris, if you look really hard.
Notice how the lack of a chimney cricket has allowed the debris to be gatherd up behind the chimney. There is actually a maple tree growing behind that chimney. Not something your home inspector really wants to find. A cricket would have prevented this build up. Hopefully this will be cleaned up before it gets out of control and does some damage.
As a rule of thumb, chimney crickets are recommended on chimneys that are over 30" wide. Do not be fooled by this rule however. If you are having problems with debris behind your chimney that is less than 30" wide, you may still want to consider a chimeny cricket. A good home inspector will note the absence or presence of a chimeny cricket for you, and may also make recommendations as to the effectiveness of a chimeny cricket.
If you are unable to access your roof to see behind your chimney, hire a home inspector or other chimney professional to do a proper examination of the area to see if a chimeny cricket is needed behind your chimney. If a chimeny cricket is needed, hire the proper professional to do the work for you, and have it inspected upon completion of the work or repair.