Appropriate Chimney height varies by chimney type, manufacturer, and the size of your house (two story houses require longer chimneys than single story). To function properly, a chimney should be at least 10 to 12 feet tall. In addition to this length, Los Angeles Building Code Requires that the chimney be three feet above the roofline, and be two feet higher than the roof line within a 10 foot radius of the chimney stack. This prevents backdraft and allows space for any burning embers that escape the chimney to cool off before landing on the roof.
A Spark Arrester helps prevent sparks and embers from getting out of the chimney and landing on your roof. The area around the top of the chimney should be clear of debris, tree branches and leaves, or any other building structures. Chimneys that are too short can cause smoke to get sucked back into the house because of back draft. If your chimney is ‘smokey’ talk to a chimney repair company. They can extend the chimney height.
If you have had a chimney inspection, you can sometimes just send the chimney inspection report to a chimney contractor to get estimates, otherwise you will have to call a chimney repair company and set up an appointment with an estimator.
Common Repairs and Costs:
Complete Chimney Masonry Rebuild- $20,000 to $25,000 for Single Story.
Install New Metal Chimney: $5,000-$10,000. $5,000 just for the stack, $10,000 if the stack and firebox. You can keep cost down by stuccoing the chimney instead of rebuiding with stone veneers.
Install New Spark Arrestor:
Chimneys missing a spark arrestor is one of the most common thing I see. If your chimney doesn’t have something covering the flue- water when it rains will just go straight down the chimney and into your house which is not good. In addition to keeping water out of the inside of your house, spark arrestors prevent burning embers from traveling up the chimney and escaping. Burning embers can start fires. While you may not want to keep Santa Claus from visiting you at Christmas, you definitely don’t want animals looking for a warm, safe, sheltered space to make home. Some common chimney intruders are Birds, Squirrels, Raccoons, Bats, and Roof rats. Spark Arrestors are really easiest to install. Cost $400 – $500
Water Should flow away from the Flue so it doesn’t get inside the chimney
New Chimney Cap: Overtime the cap of the mortar of the chimney can weather and crack since it is outside in the elements. Like drainage around the foundation of your house, you want water to be channeled away from the flue of your chimney, where it can get inside and cause mold, water damage, or wear out your chimney faster. Cost:
Chimney Extension: Chimney can sometimes be too short to get proper ventilation, or meet code, or prevent embers from escaping. extending the chimney adds a few feet of extra feet of height to the stack. If you are on a budget you can extend a chimney with a sheet metal flue extender and save some cost. Sheet Metal Extension Cost $1,000 Masonry Extension Cost $3,000
Parge Coat: The Mortor between bricks in Chimney Fireboxes can wear out over time allowing some of the heat and burning embers to escape the firebox into the cavity in the wall. This is a fire hazard. Resealing the firebox with a Parge Coat gives your chimney new life. Cost $1,000 to $1,500. The cost depends on if the damper needs to replaced (extra $200), and how big the firebox is. A normal size firebox is the $1,250 range- a huge firebox like you might find in Beverly Hills or Brentwood house on a 3 story chimney could be $2,000 or $3,000 to coat.
A note for condos: A lot of chimney repair companies do not like working on chimneys in condo buildings because the HOA can be difficult to work with. There are only a few companies I know of who do them.
Chimney Inspections have been around in Los Angeles for about 10 years. They are a specialized inspection that focuses solely on the Chimney. Due to the highly technical nature of Chimneys and the difficulty in inspecting them without the proper equipment (Telescoping Rods, lighting, and video camera), most General Home inspectors won’t be able to tell you much, if anything, about the condition of the chimney, and whether it is safe to use or not.
I always recommend a chimney inspection if the property has a chimney (including condos). Chimney inspections are pretty common now, so expect your future buyer to have one when it is your turn to be the seller. Most people only use a chimney a few times a year during holidays, if at all. Sellers have caught on to this, and are not giving out big credits for $10,000 or $20,000 like they use to. You might see in listing remarks “fireplace is decorative only”. Sellers are excluding chimneys from credits and selling them as is. Even if you can’t get a credit for the chimney, it is good to know what is going on with it and to make sure it is safe if you want to use it.
A Chimney inspector, will visually inspect the firebox, including the screens, gas connection (if present), the damper, and flue. They will elevate a camera through the flue chamber to check for cracks, gaps, or bad connections. Anywhere that heat can escape from the chimney into the walls is a potential fire hazard. The inspector will go on top of the roof and give a slight push to the chimney stack to see if it moves. They will also inspect the connection of the chimney at the roof line. This area needs to be properly flashed to prevent water intrusion into the house. They will inspect the chimney cap and spark arrestor, and evaluate the height of the chimney.
Mike Rees the Chimney Guy inspecting a condo fireplace
Many single family homes in Los Angeles built between 1920-1940 have masonry brick chimneys that burn wood. These Chimneys have the most problems. They are coming up on 100 years old and almost always require maintenance and chimney repairs (the mortar that creates a fire barrier between the bricks and your house starts to turn to dust at around 100 years).
1920s Masonry Chimney Diagram
Original Masonry Chimneys were constructed without flue linings which help support the weight of the chimney and prevent smoke escaping from grouting cracks within the stack.
Inside Chimney View
Masonry Brick Chimney with NO Flue Lining
Masonry Chimney with Clay Flue Liner
The chimney stacks on these chimneys are made of bricks, and are extremely heavy. This weight tends to make the chimney crack and shift or lean away and seperate from the house. A chimney that wobbles when light pressure is applied is a earthquake safety hazards- it could topple during a quake.
This Chimney Wobbled when slight pressure was applied and needed to be replaced
As part of the clean Air act, beginning in 2009 the city of Los Angeles banned wood burning fireplaces from being built in new construction. Old wood burning fireplaces are grandfathered in, so if the property has one you don’t have to worry about losing it.
Technology has improved a lot since 1920s-30s. Chimneys are built smarter today. Back then, the chimney stack was made of all bricks. There are two problems with building a chimney like this:
1) The bricks are extremely heavy, which can make the chimney sag from its own weight or separate from the house over time
2) The heavy brick chimneys had no reinforcement and may be in danger of collapsing during an earthquake
Chimney contractors nowadays build chimneys with a lightweight metal flue, and surround it in wood framing.
Metal Chimney Diagram
If you want the classic look of a brick chimney, worry not, you can have the chimney stack covered with brick veneers to give you that authentic brick look, without all the weight.
This Chimney Stack was replaced by Parkstone Construction in a 1920s home Hancock Park. It has a metal Flue, and was covered with Brick Veneers. You can’t even tell the difference!
For a more affordable option, the chimney stack can just be stuccoed.
Stucco Metal Chimney
The mortar that was used in Masonry Brick Chimneys in the 20s and 30s was a mix of lime and sand- Portland cement (also known as gypsum concrete) was added to mortar mix later for chimneys built in the 40s and 50s on and tends to weather far better. The old mortar in these chimneys turns to powder over time, and often requires a new parge coating to be sprayed within the firebox and/or a new liner, or heat shield installed to reinforce the brick chimney stack. Modern building practices no longer construct brick chimney stacks. Brick is fine for the firebox, but modern building techniques favor a much lighter prefabricated metal flue chimney stack contained within a framed chase covering. Home owners that desire a consistent brick look with a brick firebox can have brick veneers cut and stuccoed over the framed chase structure.
Inside framed chase of metal chimney
Gas fireplace systems like you find in condos tend to have much less problems and are less costly to fix. The main issues that come up with gas chimneys is improper installation.