Repairing Guides

how to repair cinder block chimney

by Prof. Willis Hoppe Published 3 years ago Updated 2 years ago
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Chimney Repair - how to repair a cinder block chimney.

  • First you need to prep the cinder block. Scrape off as much paint as you can and chip away any loose sections. ...
  • Next, brush off any loose dust with the masonry brush and brush on the masonry glue. This will help the cement bond with the cinder block. ...
  • Now you are ready to apply the cement. I used approx 3/4ths morter mix and 1/4 portland cement. ...
  • After I had all of the holes and gaps relatively smooth I applied a thinner coat over the whole thing and textured it. ...
  • Let the cement cure for as long as possible by lightly wetting it and covering it. ...
  • I did my Chimney in sections over a period of several days, but I imagine the more you can do at once the stronger the overal bond will be.
  • Once everything has cured seal it well with 2 coats of Dry-Lock or a similar masonry sealant and paint.

Part of a video titled How to Patch a Chimney - EASY! - YouTube
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Now apply the mortar to the damaged. Areas in my case it's the entire chimney. Use the pointingMoreNow apply the mortar to the damaged. Areas in my case it's the entire chimney. Use the pointing trowel mainly for cracks then use a flat trowel to really smooth it.

How do I remove a cinder block chimney?

Required Tools for this Project

  • Angle grinder
  • Bucket
  • Cold chisel
  • Dust mask
  • Hammer
  • Hammer drill
  • Hearing protection
  • Safety glasses
  • Tuckpointing tool

How do you build a block chimney?

  • Mix the mortar with the suggested portions of cement, lime and builders sand. ...
  • Lay the brinks on top of each other, building up the chimney’s walls on each side. ...
  • As you are building the outside of the chimney, lay the flue tiles at the same time and use the mortar to seal them together. ...

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Who to call for chimney repair?

You may have one or more of these typical problems:

  • Cracks in the exterior brick or masonry
  • Cracks in the chimney liner or flue
  • Water infiltration
  • Clogged chimney (often due to nests)
  • Creosote buildup
  • Loose chimney flashing
  • Separation between chimney cricket and chimney (a cricket is a small roof transition piece)
  • Poor venting

How to repair a cracked brick chimney?

Try one or all of the following:

  • Waterproof the chimney with a specially designed solution that is vapor-permeable and allows the brick to breathe out, not in.
  • Repair or replace the flashing.
  • Repair or replace the chimney crown (the top part of the chimney) if it's damaged.
  • Install a chimney cap, which is also called a rain cover. ...

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How do you repair a masonry chimney?

InstructionsRepoint the Chimney Brick Mortar. Mortar holds bricks together. ... Caulk Around the Flue and the Crown. ... Patch Cracks in the Large Crown Area. ... Patch Hairline Cracks With Sealant. ... Repair Cracked Bricks. ... Replace Cracked Bricks.

How do you cover a cinder block chimney?

A cinder block chimney is not exactly attractive. You can cover it up with an application of stucco, which will give it a more appealing finish. Stucco is similar to concrete. It has cement in is as well as sand, but it also has lime, which creates a slightly different texture.

Can you use cinder blocks for a chimney?

Concrete chimney blocks are 24 inches square, with a hole at the center that is sized to fit a section of vertical ceramic flue tile. Using these blocks makes the construction of a chimney faster and easier and allows it to take up less space than if it were made from conventional concrete blocks.

How do you waterproof a concrete block chimney?

Fix any cracks in the mortar, or if the chimney is severely damaged re-point the chimney. Use a waterproofing sealer, like this one found at homedepot.com which is a silane/siloxane blend that will waterproof and protect your chimney from future leaks and water damage for over 10 years.

How do you fill concrete cinder blocks?

1:447:46How To Fill Block Foundation Wall With Concrete! Concrete Pump Truck!YouTubeStart of suggested clipEnd of suggested clipAnd it's a special pump mix a little bit thinner got a different rock in it so to go down to theMoreAnd it's a special pump mix a little bit thinner got a different rock in it so to go down to the bottom of those and once it dries it'll cure out with that rebar and it'll make the block wall. Strong.

How do I reface my outdoor chimney?

The refacing process involves installing either a stone veneer or a faux stone, which is prefabricated mortar designed to look like stone, to cover your existing brick masonry chimney. A key advantage of stone is the water protection it provides.

Will cinder block hold up to fire?

Are Cinder Blocks Heat Resistant? Cinder blocks are heat-resistant, non-flammable materials. Cinder blocks will absorb the heat from a fire and protect you from its sparks. However, even though cinder blocks are heat resistant, they aren't fire-rated, and prolonged and repeated fire exposure will make them crumble.

How much heat can cinder blocks handle?

But heat them to over 392 F (200 C), and high-performance concretes become vulnerable. They can even explode, sending chunks of concrete shooting away from the main block.

What is the difference between a cinder block and concrete block?

Cinder block is fabricated of- concrete and coal cinders. Concrete block is produced by steel, wood, and cement. Cinder blocks are lighter than concrete blocks. A concrete block contains stone or sand which makes it heavier.

Can You Use Flex Seal on chimneys?

Flex Seal will work on roofs, gutters, skylights, windowsills, flashings, downspouts, foundations, awnings, chimneys, vent pipes, RV's, campers, trailers. It can be applied to wood, copper and other metals, concrete, masonry, glass, fabric, plastics and much more.

Is Drylok good for chimneys?

DRYLOK® Masonry Crack Filler seals, waterproofs and repairs cracks and mortar joints in concrete sidewalks, walls, steps, chimney crowns and floors. It dries to the color of concrete, will not bleed, and cleans up in a jiffy with just soap and water.

What is the best sealer for chimney?

While polyurethane does have its strengths related to its fairly low price, silicone is by far the superior choice when choosing a chimney sealer. Silicone is an inorganic substance that has high toughness against temperature fluctuations and UV rays.

How do you cover up an old chimney?

If you want to seal your fireplace off for good, the easiest way to do so in a hurry is to cut out a foam insulation plug, place it at the bottom of your chimney, and caulk or weatherstrip it in place.

How much does it cost to remove a cinder block chimney?

The cost to remove a chimney averages between $2,000 and $4,000 for a full removal, including debris disposal. However, chimney removal costs vary from one chimney to the next for a number of reasons.

How do you stucco a chimney?

5:167:39Rapid set stucco over any painted brick Chimney, Plastering your ...YouTubeStart of suggested clipEnd of suggested clipAnd we're gonna color coat this entire house generally you have to let the base coat scratchy BrownMoreAnd we're gonna color coat this entire house generally you have to let the base coat scratchy Brown set a minimum of two weeks if it's summer three weeks or in the wintertime.

How do you remove a chimney block?

0:3514:48How to Take Down a Chimney From Inside a House : Remove Fireplace ...YouTubeStart of suggested clipEnd of suggested clipWell morning we're pretty high up. We actually got to take the chimney down from up.MoreWell morning we're pretty high up. We actually got to take the chimney down from up.

What happens if a chimney is a fire?

Watch out: a chimney fire, even if it does not set the building ablaze , is likely to have caused serious damage to the chimney itself, leaving it unsafe, as may other chimney cracks or movements for any reason. The risks include building fires, potentially fatal flue gas leaks, improper draft, and unsafe heating equipment operation.

What are the risks of a fireplace in a building?

Leaks into the building walls (flue gas leaks or sparks into the building interior, a fire or potentially fatal carbon monoxide hazard) Unsafe fireplaces in the building: hearth cracks, fireplace side cracks, chimney damage all present risks of sparks or smoke entering the building cavities, a fire and flue gas risk.

Can a broken chimney be repaired?

Extensive concrete block cracks, badly damaged masonry chimney flues, curved, leaning, broken masonry chimneys may need to be re-built to be safe and functional. But minor chimney damage, and chimney damage that is confined to just above the roof line can usually be repaired or re-built.

Do you have to replace bricks in a concrete chimney?

A modern concrete block chimney uses a hard-fired clay chimney liner inside the blocks and a listed or UL-listed approved chimney cap. You should not have to replace blocks with bricks. Now, call a chimney repair contractor or two in your area and let me know what they tell you.

Can you patch a hole in a chimney thimble?

Donna#N#A hole at the chimney thimble location can be patched, filled in with a combination of masonry fragments or stone or even block fragments and some cement.#N#However if there are heating devices that vent into the chimney from below this point, then you may need your Mason to be sure that the flue liner is safe and intact.

How do I repair a crack in a cinder block wall?

To repair small cracks or holes in cinder block walls, you can use concrete. First, clean any parts of the wall that you plan to repair so the cement or mortar adheres securely. Hose the wall down or scrub it with a washcloth, then use a metal file to smooth out any rough edges.

How do I chip out cinder block?

Chip out the old cinder block and mortar. Using a plugging chisel and sledge, chip the cinder block into pieces. Remove the block in chunks as you free each piece from the surrounding mortar. Chip out the mortar, then brush away any additional dust or debris before putting the new block in place.

How long does it take for cinder blocks to dry?

Set the new block in place. Slip the new cinder block in place with a trowel, then scrape away any excess mortar. Let the mortar dry for 12-24 hours, depending on the mix. When the mortar is dry and stable, it should turn a light gray color.

How do I put mortar in a cavity?

Apply mortar around the edges of the cavity. Using a trowel, add a 1 inch (2.5 cm) thick layer of mortar around the top, bottom, and sides of the empty space in the wall. Keep the layer as even as possible to avoid creating tight or loose sections in the wall. ...

How do I clean a wall that is dusty?

Hose the wall down to get rid of dust or dirt. Your wall will need to be debris- and dust-free before it's ready for repairs. Take a hose and spray the wall off to get rid of any residual dust or dirt. For more stubborn areas, scrub the dirt away with a washcloth.

Who is the founder of Go Masonry?

This article was co-authored by Gerber Ortiz-Vega. Gerber Ortiz-Vega is a Masonry Specialist and the Founder of GO Masonry LLC, a masonry company based in Northern Virginia. Gerber specializes in providing brick and stone laying services, concrete installations, and masonry repairs. Gerber has over four years of experience running GO Masonry and over ten years of general masonry work experience. He earned a BA in Marketing from the University of Mary Washington in 2017. This article has been viewed 94,685 times.

Can concrete be used to fill in a wall?

Concrete is usually enough to bind together minor wall damage. If the cracks or holes don't take up the majority of the block or extend to more than a few blocks, try using concrete to fill in the damage. ...

What is a Chimney Brick?

A chimney brick is a type of masonry unit that makes up the interior structure and exterior walls of a traditional fire place. These bricks are made out of clay, sand and straw which gives them their distinctive yellowish orange color when they’re fired in a kiln at high temperatures.

Types of Chimney Bricks

Different types of bricks have different properties in the chimney. The bricks are divided into two main categories, standard and refractory. Standard brick is made for normal use because it does not withstand high temperatures well compared to other materials used in a fireplace or stove lining.

How to identify the problem with your Chimney Bricks?

Your Chimney Bricks may be damaged because of weather changes or heat exposure. The bricks lose their flexibility and crack easily under stress or weight. This is a common problem that can affect the structure of your house over time if you don’t take care of it immediately.

Why are my Chimney Bricks Crumbling or Loose?

One of the most common reasons for your brick to be crumbling or loose is because it’s old. Chimneys are typically built with bricks and mortar, so over time those bricks can begin to crack and crumble as they break down.

Types of Mortar for repairing Chimneys

There are many types of mortar that can be used for repairing a chimney. The most popular type is called Portland cement mortar, which is made from portland cement, sand, and water. It is durable and weather-resistant, making it the perfect choice for repairing a chimney.

Tools you will need for a Chimney Bricks repair

A bucket of cold water, protective gloves and glasses are the tools you will need for a Chimney Bricks repair. Make sure to also check your local building codes before beginning work. It is not uncommon for homeowners in many different parts of the country to be required by law to stop or fill up any holes that could pose safety hazards.

How to repair a Chimney Bricks Step by Step?

It is possible that you are facing some problems with the bricks of your chimney because it has been built many decades ago. There might be cracks in the mortar and therefore, water may get inside leaking to other parts of house which can lead to serious consequences. Here we will discuss how first step should be taken:

How to repair cracks in chimney crown?

Large cracks on the chimney crown between 1/8 and 1 inch in diameter can be repaired with pre-mixed cement patch or mortar. Inject the repair mix into the crack with a squeeze bottle, or force into the crack with a putty knife. Curing time typically ranges from four to six hours, but it may take longer for wider cracks.

What is the worst thing about a chimney?

Even worse, cracks in a brick chimney that continue from the flue to the exterior are one cause behind a terrifying, devastating phenomenon: a chimney fire. Chimney fires can ignite instantly—those who have experienced them describe it as an explosion followed by a sound similar to a freight train. Once a chimney fire has started, only the fire department can stop it since it must be extinguished from the top-down.

What holds bricks together?

Repoint the Chimney Brick Mortar . Mortar holds bricks together. New mortar is smooth and solid, but as the seasons go by, the elements batter the mortar , causing it to crumble. Since mortar is softer than brick, the mortar will always deteriorate first.

What is the best way to fix a hairline crack?

The solution is to use a water repellent that is highly liquid in consistency, which can penetrate the hair line cracks.

How to clean cracks in brick?

With a gloved finger, wipe the mortar clean from the crack. Use a rag to clean the area around the crack. If the brick cracks are very thin hairline cracks, you may be able to close them up by brushing them with water repellent. Lee Wallender.

How to scrape out crumbly mortar?

Repointing, or tuckpointing, is the process of scraping out the crumbly mortar and replacing it with new mortar. Use a joint raker to scrape out loose, weak mortar, leaving the good mortar in place. For more difficult crumbly mortar, gently tap it out with a hammer and masonry chisel.

What is a patch in a chimney?

Patch Cracks in the Large Crown Area. The chimney crown is a sloping cap that forms the top-most section of your chimney. Its purpose is both to protect the masonry section of the chimney and to prevent water from pooling on top.

What is a crack in a chimney?

A crack in a chimney can be very evident, like in the photo below: Chimney Crown with cracks! The purpose of your chimney is to properly vent the products of combustion (smoke) form your home. However, if the integrity of a chimney is compromised, say from a crack, this can be an issue.

How much does it cost to repair a chimney?

However, chimney repair services can range from $250 to several thousand and up depending on the extent of what needs to be repaired. According to a 2019 Home Advisor article, a masonry chimney repair can cost $1,000-$3,000 from the crown to the roof or over $10,000 if the entire masonry chimney must be rebuilt.

What is a chimney made of?

Chances are if you have a chimney at your home – it’s most likely a masonry chimney (unless it happens to be wrapped in siding). A masonry chimney can be constructed using a variety of masonry (think stone) and metal materials including: Brick, Mortar, Concrete, Concrete block such as cinder-block. Stone,

What happens if you have an improperly designed chimney?

An improperly designed chimney can cause anything from a funky-looking chimney to some extreme issues, such as fire hazards. One time a roofing company called us while replacing a roof to tell us about a damaged chimney, that was poorly designed.

What causes a fire in a chimney?

In doing research, the most common cause of home fires is smoking, followed by cooking and electrical malfunction. While many of the common home fire causes are controllable, some like electrical malfunctions or faulty masonry chimneys aren’t as easily diagnosable. However, when diagnosed a masonry chimney is nothing to wait around for, ...

What is the top of a chimney called?

The very top of a chimney is referred to as the “Chimney Crown.” Think of a king with his crown, you would notice a few things if the king’s crown was:

Can a masonry chimney be damaged?

Some masonry materials can be susceptible to weather and rain, especially if improperly installed. Not only can your damaged masonry chimney look bad, it can also be extremely hazardous! Some chimneys might have issues, which is why it’s good to know when and if a masonry chimney needs to be repaired!

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