How Can I Tell If I Have a Leaky Roof or a Chimney Leak?
A good rule of thumb is; if the leak appears on every rain or during melting snow then it’s a roof leak, if the leak appears intermittently, it’s a chimney or chimney flashing leak.An intermittent leak, which is a leak that does not appear on every rain, is caused when wind blows rain from a certain direction against a failure in the chimney or chimney flashing.
What Does a Chimney Leak Look Like?
Damage from a leaky chimney often shows where the chimney abuts a wall. The ceiling or wall will be stained, the paint peeling or on plaster a white chalky substance called “efflorescence” will appear.
What Causes a Chimney Leak?
Moisture penetrating your chimney, outside moisture is rain, snow or melting ice, inside moisture is from the hot water heater or furnace.
Outside moisture will penetrate through a damaged or missing chimney crown, failed pointing, spalling bricks, improper chimney flashing and a missing chimney cap.
What is a Chimney Crown?
The top of a chimney has an opening to exhaust the smoke and fumes. A terra cotta flu pipe should be installed and a thick layer of concrete, which is known as a chimney crown should be poured covering the opening and abutting to the flu pipe. The chimney crown should extend a few inches over the outside walls of the chimney so that water will drain away from and not run down the chimney walls. A properly constructed chimney crown is your best protection against chimney damage.
A chimney without a proper crown is like a toothache, ignore it and it will turn into a root canal. I’ve seen chimneys fall down simply because the lack of a chimney crown.
What Causes Damaged Bricks and Pointing?
The lack of a chimney crown is the main cause allowing water to penetrate the bricks. On a warm winter day bricks will absorb moisture then during the colder night time temperatures moisture freezes and expands causing cracks and splits in the brick.
This damage is called “Spalling”. Typical spalling is cracks, splits in the brick or flaking.
Another type of spalling is caused when the wrong mortar for pointing is used with soft brick. Bricks absorbs moisture but hard mortar does not. Bricks will expand as they absorb moisture, the hard mortar does not, causing the brick to split. Using the correct mortar is especially important when working with older brick in historical chimney restorations.
What is Chimney Flashing?
Where-ever the roof meets a wall, a flashing system should be installed to prevent water from penetrating between the wall and the roof. A flashing system is a two part system; step flashings and counter flashings. Step flashings are L-shaped and are installed between each course of roofing. The bottom of the L is installed on the roofing and the upright part of the L abuts the wall. The counter flashing is installed over the step flashing. We install Reglet Counter Flashing, which is cut into the wall and won’t fail. Mechanical Counter Flashing, also known as Philly Flashing, is caulked to the wall and will fail with-in a few years.
Why Is There Moisture in My Fire Box?
The most common cause of moisture in a fire box is the lack of a chimney hood. A chimney hood is attached to the top of your flu pipe preventing water and animals from entering your chimney stack.
Excel Roofing and Siding has thirty years of experience helping home owners solve their chimney problems. Contact us today at 610.608.1023 for a free no obligation inspection and estimate.