Let's focus on masonry chimneys since they are the most challenging and one of the most common. Allowing for movement Chimneys have a foundation, which may be independent from the house. In any case, the roof deck may move relative to the masonry chimney and good flashing details anticipate this. Good chimney flashings are two-part. The base flashings are secured to the deck and the cap flashing is secured to the masonry. The overlap between these two flashings allows movement without disturbing the watertightness.
Chimney flashings - side flashing detail The counter flashing is missing on the side of this chimney. Typical materials Chimney flashings typically are made of one of the following: galvanized steel galvalume lead copper lead-coated copper Aluminum generally is not used since it is not compatible with masonry mortar.
On a chimney, flashing is required at the bottom, the sides and the top. Each of these ideally would have a base step if it's on the sides flashing and a cap counter flashing; however, bottom flashings and top flashings where there is no saddle often are one piece. Let's look at how chimney flashings are installed. Base flashing Bottom: Before the base flashing is installed, the roof is shingled up to the bottom of the chimney.
The bottom base flashing is made of a single piece of metal extending 3 to 6 inches down over the shingles that already have been installed, and 12 inches some say less up the bottom face of the chimney.
This flashing wraps a few inches around the sides of the chimney. Sides: The base flashing for the sides of the chimney is called a step flashing. Others call these soakers or baby tins.
The step flashings typically are 3 inches wide, 3 inches tall some recommend wider and taller, as much as 6 inches in each dimension and about 9 inches long. They typically are the length of the shingle exposure, plus 3 inches some say 2 inches! These base flashings are nailed to the deck. Chimeny saddle flashings Chimeny flashings - head flashing detail Cricket or saddle has been removed from this masonry chimney wider than 30 inches.
The head flashing here is not caulked or embedded into the mortar. Cricket or saddle A cricket or saddle is typical on a chimney and is required by many authorities when the chimney width is more than 30 inches.
The cricket or saddle is a peak that deflects water and snow around the chimney, preventing it from accumulating against the top side of the chimney. The cricket usually is made of the same material as the roof sheathing plywood or waferboard in modern construction. Where no cricket is used, the top flashing should extend at least one-sixth of the chimney's width up the chimney 6 inches minimum and should extend up the roof under the shingles to a height that is equal to the distance the other end of the flashing extends up the chimney some say 18 inches.
All of the base flashings are fitted against, but not attached to the masonry. Counter cap flashings Bottom: The bottom cap flashing or counter flashing is a single piece of metal that covers the vertical portion of the base flashing. Cap flashings should be fastened to the chimney only. It goes beneath the upper courses of roofing material, and overlaps the side or step-flashings.
Not Helpful 0 Helpful 3. How many inches of flashing should there be at the bottom, lying against the roof, on all four sides? For a skylight or chimney on a composition roof, there should be 6 inches on bottom and sides, 9 to 12 inches on top. Not Helpful 1 Helpful 1. I had my metal roof replaced about 2 years ago. It is now leaking pretty badly around the chimney. There is no saddle on the back.
Do you feel that is something the contractor should be responsible for fixing? Since it was two years ago, it is likely that the contractor is not liable nor responsible to fix it for free.
For home improvement projects, contracts typically have some sort of warranty period, this period is typically at most only good for one year. Check your contract and call them up to find out more. In some cases, if the product is faulty, the warranty may be longer. Include your email address to get a message when this question is answered. Measure the dimensions of the chimney and the slope of the roof before ordering the flashing pieces from a sheet metal company. Helpful 0 Not Helpful 0. Submit a Tip All tip submissions are carefully reviewed before being published.
You Might Also Like How to. How to. About This Article. Co-authored by:. Co-authors: 8. Updated: October 21, Categories: Fireplaces. In other languages Deutsch: Einen Schornstein abdichten. Nederlands: Zetwerk om een schoorsteen plaatsen. Thanks to all authors for creating a page that has been read , times. Thank you! More reader stories Hide reader stories. Did this article help you? Cookies make wikiHow better. By continuing to use our site, you agree to our cookie policy.
Jennifer Baker Aug 29, Barbara Boguski Sep 9, I hope to have the flashing repaired using the saddle technique to stop the leaks. Thank you. Don Taylor May 12, Jay Ruiz Mar 7, It is easy to install and can be used in areas that receive high amounts of precipitation. Contact a chimney specialist today for more information on how to use lead flashing around your chimney.
Keep the joints of your Lead Flashing tight and sealed with a good mastic. If there are any gaps, water can get in under the flashing causing leaks inside your chimney or around its foundation that will lead to damage over time. Remember too that it is not common for Lead Flashings to be used on their own but rather as part of a bigger setup such as around an entire house or large building.
Some flashing systems will require you to coat the materials with something like paint after installation so that water does not seep through any spaces in between each sheet of Lead Flashing. This is common for metal types but may also be required for others too depending on the climate and weather conditions in your area.
Cheap imitations may seem like a great deal at first but will not last very long and may cause more damage than good in the end. Do not expect Lead Flashing to be maintenance free. While it may last for years without corroding or becoming damaged, you will need to apply something like paint over the materials after installation so that water does not seep through any spaces in between each sheet of Lead Flashings.
This is common for metal types but should also be done for others too depending on the conditions in your area.
If you are working around a gas or oil furnace, make sure to turn it off before installation begins and not just disconnect any fuel lines. It is common for Lead Flashing materials to be highly flammable so this will help prevent accidents that could result in disaster if something were to go wrong. Finally, always read the instructions that come with your Lead Flashing materials before starting installation.
This will help ensure a successful and safe job. For centuries, lead has been used to make durable and aesthetically pleasing roofs. Lead flashing is a thin sheet of lead that covers the chimney to prevent water from seeping in.
It also provides structural support and prevents damage to your home or building when it comes into contact with direct heat sources, such as chimneys and furnaces. The use of lead for this purpose dates all the way back to the Roman empire. Lead flashing can be installed in a variety of ways, but the most common is to use it as a cap on top of the chimney.
The first step is to measure the width and length of the chimney opening. Next, cut a piece of lead flashing that is slightly larger than the measurements. Fold the lead flashing in half and then place it over the chimney opening.
If you have a brick or stone wall, cut a piece of sheet metal that is slightly larger than the measurements and secure it around your chimney with lead nails. Then use plumber's putty to seal any cracks between the flue tiles and other building materials. Finally, seal the lead flashing with a high-temperature silicone caulk.
Lead flashing is available in a variety of thicknesses and colors. The most common type is black, but it is also available in gray, white, and other colors.
When choosing a lead flashing, make sure to select one that is suitable for the type of chimney you have. A good general rule is to choose a lead flashing with 0.
Then use plumbers putty to seal any cracks between the flue tiles and other building materials. Lead flashing is a great way to protect your chimney from water damage. Thanks for reading! For many years now, I have been researching different types of fireplaces to help me decide which one would be the best for my home. After a while of research, I decided that pellet stoves were the best option for me because they are cleaner than other options on the market.
That's why created this website — so others can learn about all sorts of fireplace options available to them so they can make an informed decision about what kind will work best in their home too!
0コメント