The importance of proper cricket flashing behind chimney roof valley

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You are living in a zone of hefty rains and dense snowfall and that’s why you have this pitched or slanting roof above you. This is because you know that the best way to avoid ingress of precipitation is to drain it away as quickly as possible.

What if you were shown that regardless of having these lofty slopes, your roof is inundated by snow dams and water ponds? And icing-on-the-cake is that the culprit is chimney, the stack which vents out hot smoke from your home.

When would you require a chimney cricket on your roof?

When the chimney of your house is located at downward slope of your roof and is more than 30 inches in width; it is likely to form a chimney roof valley. This valley if left unattended would allow the seeping water to accumulate.

This accumulation is perilous for masonry of the chimney as well as for your roofing system. As this area is behind the chimney wall it is therefore least noticeable from the ground; because of this reason it is mostly overlooked by the property owners and realtors. The situation would even get worse when the temperature drops and in the time when the water pond behind chimney freezes.  

Roofing experts have been using a remedy and a trick for avoiding it and shedding the rain water, snow and debris with the help of a raised and little crested roof top called a Chimney Cricket. This Chimney cricket (also termed as saddle) is introduced on the higher side i.e. the back side of the chimney. Depending on the type of material from which it is built; there are several types of chimney crickets.

In ordinary circumstances, the cricket can be built with aluminum, stainless steel or galvanized steel in a triangular shape in cross-section with sides angled in a way to divert / glide the splashing water. Although as a guideline it is recommended to have a chimney cricket even if the width of the chimney wall is less than 30 feet. There are many factors that contribute and you always don’t want to replace the complete roof assembly just by saving few bucks initially.

Importance of Flashing around Cricket of Chimney Roof Valley

Now that you have cricket on your chimney roof valley and still a property inspector informs you that you need complete roof repair due to damage done by the ingress of water and poor roof drainage. It is because the cricket of chimney roof valley has leaking spots and that is just because of improper flashing around the cricket-chimney-roof joints.

What is chimney flashing?

In the simplest of meanings, the flashing is the metal sheet that overlaps the roof chimney treatment and makes it watertight. In case of a chimney guarded against leakage by a cricket the problem with faulty flashing even makes it worse for you. The roof inspection for faulty flashing would be difficult to diagnose in such cases.

It is therefore of utmost importance, to use multi-layer flashing or step flashing in a section lapped up.  In the absence of such a flashing, your roof sheathing and the ceiling below would be in a big irrecoverable trouble.

We recommend you to use flashing and counter-flashing, the metal sheet is woven with the shingle course and is then lapped with the side of the chimney followed by counter-flashing. In which metal is fixed with the chimney masonry joints and is overlapped with the previous step flashing.

Although in most of the areas, the flashing is carried out by galvanized steel and aluminum sheets but if your budget allows you can use one made of copper which has a longer life span. It actually depends on the type of area you are living in, your budget and the easy availability of flashing material.

David Noah

Howdy, I’m Noah Although I don't like all this internet thing but I love sharing my stories on the roof here. With my years of experience in number of roofing contractors across various boroughs of Florida, I'm here to answer all your roofing questions. I'm really honored to have you on my website browsing through our articles and hope you'll enjoy your visit and find my content helpful in every situation. You can contact me right away to discuss any of your roofing problem.

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