Category Archives: Chimney Crowns

A chimney crown is placed atop the masonry chimney as a form of protection for your chimney against the weather. Damaged, poorly made, or missing chimney crowns can result in damage to your bricks or a leaky chimney. Chimney crowns are especially important in regions that face sub-freezing winter temperatures. Read our articles below to learn more about chimney crowns.

Chimney Checklist

The first step in making sure your chimney is safe and serviceable is to get a chimney inspection. When you get a professional to inspect your chimney you’ll receive a report of what it looks like inside and outside.

Levels of Chimney Inspections

Chimney inspections have “levels” with Level 1 Chimney Inspection being the most basic. It’s simply a visual inspection of whatever is easy to see during cleaning.

You probably want a Level 2 Chimney Inspection which involves looking at all the accessible areas (the attic, crawl spaces, etc) and, while not required, usually involves the use of a chimney camera to examine the flue tiles. A Level 2 Chimney Inspection is required (by NFPA and most codes) when changing appliances hooked up to a chimney, after a chimney fire or earthquake, and before a real estate transfer. This is the law in Maryland.

In your chimney inspection, the sweep or inspector should:

Check for cracks and weathering

Check for cracks and weathering in the masonry and the mortar joints. That means looking at the bricks themselves, the joints between them. If there are cracks in the brick or bad mortar joints here’s what needs to happen to fix it:

  • When there’s a lot of bad brick at the top, the best solution is to take the chimney down and rebuild it.
  • If there are a lot of bad mortar joints, take the chimney down and relay the brick. If the bricks are in good condition you can certainly re-use the bricks and, in fact, should for aesthetics – you want to match the bricks below if you can.
  • If the damage is more minor, “re-pointing” is an option. This is where you remove a few bricks individually or where you just put some fresh mortar in where old mortar Is worn out. This is an OK solution for small problems, but it’s a terrible solution when a masonry structure is just plain worn out. It would be like putting a Band Aid on a cut artery. Keep in mind that repointing is aesthetically poor as the new mortar or brick is not likely to match the rest. Rebuilding is best option

Check for cracks in your crown (the cement on the top of the chimney)

Again, you make a difference between “big damage” and “little damage.” If your crown is anything but perfectly sealed, you do need to fix it because this is where all the damage below begins. Water that enters through the top of your chimney freezes and thaws all winter long, in time ruining the structure below.

If you have crown damage, here’s what needs to happen to fix it:

  • Big cracks and masonry that is outright coming up in your hand obviously needs to be replaced. The whole crown should be removed and replaced with concrete. A lot of crowns were made with mortar mix and that’s not good- use concrete.
  • If on the other hand you just have cracks in the top (and fact is most chimneys do) then you will be all right with simply sealing the crown. There are good latex sealants these days which hold for a very long time when properly installed.

Check for stability

It is not uncommon to see chimneys leaning away from the wall. What to do is not clear cut. If the chimney is leaning it’s very likely because the foundation of the chimney isn’t right. In any case, either the chimney moved away from the house or the house moved away from the chimney.

If the chimney is built as part of the foundation the house sits on, and had not broken away, then it’s safe to say the house moved somehow. To know this, you must dig around the base of the chimney to actually inspect the foundation.

If the foundation is good, here’s what needs to happen to fix the problem:

  • You either have to tear down and rebuild the chimney or you must caulk the opening. More likely though, the chimney foundation was never part of the poured concrete of the house’s foundation and it has a “movement life” of its own. If so, here’s what needs to happen to fix it:
    • First, tear down the chimney. Then take out the old foundation. Then dig the hole deeper (another couple feet maybe?) and pour a new concrete foundation. Finally rebuild a new chimney.

I know nobody wants to hear that and I know lots of people think about strapping the chimney to the house and drawing the bolts up tight. It is not a good solution. First of all, it may be illegal. More importantly, it doesn’t really fix anything, it only closes a gap. The chimney comes under new stress and will break in the middle, given some time. Don’t think about straps. It’s more of an 1800s thing.

Check for clearances from combustibles

A chimney professional will know code-specific things to check for, but anyone can make sure their chimney complies with the “3-foot, 2-foot, 10-foot rule.”

chimney roof clearance - the 3ft x 2ft x 10ft rule

Take a look at the picture and you’ll understand immediately.

If your chimney doesn’t comply, here’s what needs to happen to fix it:

  • In almost all cases, the solution is to raise the chimney. This can be done by adding rows of brick to a brick chimney, or by adding lengths of factory built chimney both to masonry or factory built chimneys. It looks a bit odd coming off the top of a brick chimney, but it is legal.
  • Check the inside of the chimney- the flue tiles (liner.) Check the liner for mis-aligned tiles, for spaces between tiles, check for cracks or broken sections of tile liner. Check for “spaulling” i.e. little bits of the face of the tile breaking loose and building p at the bottom of the flue. The only way to really know is by video inspection. When you call your chimney professional, be sure to insist that you’re getting a video inspection. If not, hire someone else.

If you have any of the above situations, here’s what needs to happen to fix it:

  • Pretty straightforward really- you need to reline that chimney. The particulars of how that’s done vary so much from one chimney to another that I can’t possibly cover it here. Suffice to say that the one thing you should ask for is to have the old tiles removed. It will cost more and a lot of chimney people would rather not do it because it’s not fun work. But this is your house and you want it done right if at all, right? Have the old tiles removed. The reasons are usually related to proper sizing and to the fact that there is probably creosote on the outside of the tiles where nobody can see it (but it can still catch on fire.)

Check for obstructions

These are usually obvious when cleaning a chimney. Or perhaps you have a tree hanging right over the chimney. If you have an obstruction, here’s what needs to be done to fix it.

  • Just get it out of the way. Overhead branches too close? Cut them off. Bird’s nest in the chimney? Remove it. Debris at the base of the flue? Remove it. This one is obvious what to do, you just need to check to see if any problem exists!

Check for cleanliness

Sometimes a chimney is obviously clean just by look at it. If you can’t say that for sure just looking at it, then play it safe and have the chimney swept.

Check the connections

Wood stoves, fireplace inserts, gas or oil burners and hot water heaters all have pipes that connect those appliances to the chimney itself. They should be secured with three screws at every joint, have an uphill incline, be the right size, attached or joined to the chimney well and have proper clearances to combustibles. Make sure your chimney inspection includes all of these elements. And if something is wrong, here’s what needs to happen to fix it:

  • it varies. Regardless, you need every one of those points to be in order. A bad connection is every bit as dangerous as a bad chimney. Probably more dangerous actually, so pay close attention to connections.

This should give you a good overview of what you want in your chimney inspection and what to listen for when the inspector tells you what needs to happen to fix any problems.

Your Source for Fireplace and Chimney Information

The following library of information is broken up in a way that will educate you on your chimney so you know how your chimney should be properly cleaned, maintained, and/or repaired. If you can’t find what you’re looking for, leave us a note in the comments and we will try to find you an answer!

The Basics

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Chimney Crown with Flue Caps

Chimney Caps and Chimney Crowns: Chimney Masonry Maintenance 101

Chimney Caps & Chimney Crowns: Essential to Masonry Chimney Maintenance

Proper maintenance of masonry chimneys extends past the brick work. Chimney caps and chimney crowns are both important for the longevity of your masonry and the safety of your home. Both caps and crowns help protect your masonry chimney interior and flue from precipitation, and the damage freeze and thaw cycles cause.

Chimney Crown with Flue Caps

Chimney with crown and 2 capped flues

Chimney Crowns

The chimney crown is placed atop the masonry chimney as a form of protection against the weather. As crowns withstand a lot of abuse, they need to be made out of a solid material; most commonly, chimney crowns are made of poured concrete and free from cracks and crumbling.

As its primary purpose is to protect your chimney, it should overhang the masonry by at least 2 inches. The top should gently slope away from the chimney opening, encouraging precipitation to run away from the chimney interior. The overhang prevents this water from running down the masonry, and a slight ridge build into the underside of the masonry further encourages the water to drip onto the roof rather than reach the masonry.

Chimney Caps

Copper Chimney Cap

Jim and a shiny new copper chimney cap

Chimney crowns do not cover the chimney interior. Chimney caps serve this purpose. Generally made of metal, they are installed just inside the chimney opening and extend well above the chimney to allow proper venting and draft. They prevent water from falling directly into your chimney, and also help keep out birds and small animals attracted to the warmth.

While most chimney caps are relatively simple, they are not always interchangeable. Chimney caps can affect your chimneys draft and certain styles work better than others with different vent sources.

For example, wood burning fireplaces or fireplace inserts produce creosote and other combustible solids. Not only will these accumulate in your flue, they will also build up your chimney cap. This is specifically a problem if your chimney cap has a protective mesh. As it accumulates, it causes draft problems that can make your fireplace unpleasant and unsafe.

Top Sealing Dampers

Top Sealing Damper

Up close and personal with a top sealing damper

In addition to simple cap styles, you have the option of added functionality. Top sealing dampers, otherwise known as “Top Dampers”, serve the function of both cap and damper. They affix to the top of your chimney much like any other cap, but can be opened and closed to allow venting. These easy to use top sealing dampers are connected to a switch near the fireplace, and with a quick pull of a lever the damper opens and closes. They’re constructed to prevent small animals from entering the chimney when open while shedding most rain, and to seal tight against water and air when closed.

While these top sealing dampers are of particular interest in older homes where the original damper is missing or broken, they can be of great benefit to most homes. They increase energy efficiency by preventing heat loss and down drafts. Relatively simple to install, most homeowners are surprised by how much top sealing dampers can save them in energy costs.

Chimney caps and crowns are an important component of masonry chimney maintenance. If you have any questions about chimney caps, crowns, or top sealing dampers, contact a trusted chimney professional. And of course, if you’re in the market for a trusty chimney professional in the Washington D.C. area, we’d love to work with you to ensure your chimney is safe and functional.

How Many Things Can You Put On One Chimney? Or Multiple Appliance Venting

Let’s start with a few definitions.

chimney flue ventingAppliances include fireplaces, woodstoves, furnaces, boilers, pellet stoves, hot water heaters, etc. They’re all individual appliances.

A chimney is a structure that has one or more flues in it.

A flue is simply the chimney passageway that vents the fumes from whatever is attached to it. (A flue is not the same as a damper either; a damper is something that can block the flue.)is simply the chimney passageway that vents the fumes from whatever is attached to it. (A flue is not the same as a damper either; a damper is something that can block the flue.)

How many appliances can you have per chimney?

And even though the question always comes across as “how many on one chimney?” let’s make sure to discuss “how many on one flue?” The answer to the question is: “It Depends”.

The rules are found in various NFPA standards and in the IRC (International Residential Code.) This article is general in nature but for those who want to drill down into the details, most of the information can be found in IRC chapters 10, 13, 18 and 24.

Solid fuel burning appliances.

Solid fuel includes coal or corn or cherry pits, but for most of us that means cord wood or pellets. The rule here is easy and clear.

IRC M1801.12 (PDF Here) Multiple solid fuel prohibited. A solid-fuel-burning appliance or fireplace shall not connect to a chimney passageway venting another appliance.

In other words, only one appliance per flue, period. It goes without saying, I hope, that gas or oil appliances cannot be vented into a flue which also vents a solid fuel appliance. EVERY SOLID FUEL APPLANCE GETS ITS OWN VENT!

How about hooking up a woodstove into an existing masonry fireplace flue?

That’s OK as long as:

  • The fireplace has been blocked off. Remember, only one appliance per flue!
  • The liner for the woodstove has to be properly sized, which generally means the same size as the collar-size coming from the appliance.
  • Make sure the chimney is clear of combustible materials before inserting the smaller liner.

Gas and Oil Appliance Venting

Gas fireplaces are factory-built systems. The manufacturer’s listing and instructions will preclude attaching any other appliances to it.

Multiple gas or oil furnaces or boilers, as well as hot water heaters, can be vented into one flue. There are a few rules to mention:

  • The rules apply to listed appliances. While I have never seen an unlisted gas or oil furnace in my life, if you have one, you are referred back to the rules for solid fuel burning appliances- one per flue.
  • If venting two or more appliances on the same flue, you have to know the flue can handle it, as determined but the BTU input and other factors.
  • Both or all appliances have to be on the same floor. So, no furnaces in the basement or room heaters on the second level of your home.
  • The connectors for the appliances have to be offset. They can’t come into the flue at the same height, and especially never directly across from each other.
  • The smaller of the two connectors go into the flue above the larger one (usually meaning the hot water heater).
  • As a general rule, don’t mix “natural draft” appliances and “fan assisted” appliances on the same flue. This rule is more complicated than this, but if this is your case, be sure you refer to the manufacturer’s instructions. Call an HVAC company and make them show you to your satisfaction it’s right. Don’t take anyone’s word for it, see it in writing.

The NFPA 54 (Gas) and the NFPA 31 (Oil) show diagrams in great detail, and cover sizing the connectors as well (connectors are the smoke pipes that carry the fumes from the appliance to the chimney flue.)

Read another helpful article by the American Society of Home Inspectors.

Five Reasons for Chimney Leaks and What to Do About Them

Causes of leaking chimneys can usually be narrowed down to five reasons. If your problem isn’t solved from addressing the items on this list, your leak probably isn’t from the chimney!

common masonry chimney leak fixes

1. The Simplest Cause of Chimney Leaking: Rain Going Straight In from the Top

Capless Chimney

Capless Chimney (source: hersheychimneycleaning.com)

It’s not hard to picture that. Chimneys without covers get a lot of rain falling straight down into them. A chimney cover makes sense to most people. Not only does it keep the rain out, but keeps birds, animals and debris out. The greatest value of the chimney cover is really keeping these out because when chimneys get blocked at the bottom, people get sick (or even die) from CO poisoning. While it’s true that sometimes an uncovered flue is the source of water problems, most often this reason for a leak is only when the liner is metal.

How to fix it

Get a chimney cover and have a professional make sure it’s not this simple.

2. Many Chimney Leaks are from Cracks in the Chimney Crown

cracked chimney crown

Cracked Chimney Crown

The chimney crown is the cement part on top of the chimney. The bricks go up around the tile flue liners, but at the top you need something to stop the rain and snow from just falling in around the tiles. You can see that the very purpose of the chimney crown is to keep rain out. Cracks in the chimney crown can occur from shifting of the structure or from shrinkage dating back to the first day the crown was put on. When your crown has cracks, the water goes right through those cracks.

How to fix it

How to fix a cracked crown depends upon how bad the damage is. Most crowns have small cracks. Even small ones need to be fixed because all big cracks started out as small ones. Water freezes and thaws in the cracks all winter long, year after year, forcing small cracks to eventually become big cracks. There are excellent crown coating materials such as Chimney Saver Crown Coat which cover the masonry and prevent small cracks from becoming a real problem.

Once chimney crown damage is significant, though, the only fix it is to remove and relay the masonry. You can’t put a band aid on a gushing wound and you can’t coat a structurally ruined chimney crown and expect it to work. Best to coat your crown now with Crown Coat and avoid the big hassle and expense later.


chimney inspectionLeaky Chimney? We can fix that! If you believe that your chimney is causing damage to your home please give us a call or schedule an appointment online. We’ll be happy to help you.


3. Chimneys Leaking From the Inside Out from Condensation

damage from chimney condensation

Damage from Chimney Condensation

I remember a lady whose wallpaper peeled where the chimney ran through the house. She knew it was the chimney because this is the only place with wallpaper peeling. She had tried everything- a chimney cover, flashing, even rebuilt the entire top of the chimney. By the time I met her she’d spent thousands of dollars but nothing fixed it.

This was an older house with an unlined brick chimney. In 1900 when it was built that chimney carried wood or coal smoke I’m sure. Someplace along the way a gas furnace was installed, but the chimney was not lined with a properly sized liner.

How to fix it

Gas fumes are very low temperature and have a lot of moisture in them. These fumes were condensing on the inside of this too-large, too-cold old chimney, literally soaking the bricks and keeping them moist all the time. All it took was a chimney liner and we solved the problem.

4. Chimney Flashing Causes Leaks

bad chimney flashing

Chimney Flashing Leaks

The flashing is what keeps water from going into the place where the brick structure comes through the roof (or otherwise comes close to the roof.) There’s a fairly large gap between the bricks and the roof and water will pour through that hole if it’s not sealed up. Flashing is often aluminum that goes in between a couple bricks and bends to go on top of the shingles. Some sort of water proof “stuff” seals those spots. Though it’s far from the best choice, the “stuff” is often tar. In any event, flashing doesn’t last forever and the tar lasts even less time.

How to fix it

There are better materials for sealing the flashing now. If you get a chimney sweep to fix your flashing, tell him you want Flash Seal by Saver Systems. (As you can see, I like Saver Systems products; but they just work well, so you can’t go wrong!) It seals better and lasts longer.

5. Chimney Leaks Caused by Leaking Bricks

leaky bricks

Leaky Bricks; Source: doityourself.com

Bricks and mortar both pass water, and often lots of it. The problem here is the same as with the crown- the freezing and thawing all winter long with the resulting damage which causes leaks in the house.

You have probably heard of waterproofing a chimney, but you have to be careful about what waterproofing material to use. When water is absorbed into a brick or a mortar joint in the summer time, the water probably dries out after a while. The exceptions might be for a surface in the shade or on the side of the house where the sun never shines; those walls just stay wet. That water does try to escape by “falling” i.e. the water weight (or head pressure) carries it toward the ground where it forces its way out of the bricks either inside or outside of the house.

If you apply a waterproofing material that physically blocks the pores of the brick or mortar, the water is trapped inside the brick. Some bricks actually get soggy, though it’s more likely that the water will just seep to the inside of the house. To the point, using silicone based water sealants may trap water and cause more damage than you started with. Use polysiloxane type waterproofing agents, such as Chimney Saver by Saver Systems.

How to fix it

To find out if your chimney leaks through the masonry surface, have your sweep do a Masonry Absorption Test (MAT) This is a simple test where a special test tube is attached to the side of the chimney and you record the time it takes for water to be absorbed into the wall. This tells you if you should waterproof the chimney.

Bonus: Chimney Leaks That Aren’t Chimney Leaks

Humid Days That Cause The Chimney To Weep

The question comes up now and again about chimneys that weep on humid days and not related to rain events.  As always, anything can be caused by lots of things, but this is probably one of two things or possibly a combination of both.

The most likely scenario is that there’s humid air, probably in the attic coming into contact with the cooler surface if the chimney masonry or tile.  Assuming this, the air inside the house is probably cool and dry (from air conditioning) so there’s some gradation from cool and dry to warmer and moister in the attic.  Where the coolness meets the humidity, there’s the spot for condensation.  Once it’s water it can run, soak, weep – whatever water might do.

If so, the solution is probably to make sure the attic is properly ventilated.

A second possibility: make sure there is sufficient replacement air to the house in general.  If your house is quite tight, condensation is a likely result.  We’re discussing humid days here, but a tight house (particularly if there are any fans at work as well) could well exacerbate the problem.  The attic can’t be properly ventilated if there’s on replacement air to the house.

While you’re at it, check the CO level in your house.  Even though we said the problem is on humid days, and maybe a tight house has nothing to do with it, since there is condensation and a tight house you’ll want to be on the lookout for spillage from a gas fired unit (presumably the hot water heater) as well.  Probably not part of the problem, but check anyway.  It’s not out of reason and CO poisoning is so common now.

Other Potential Reasons

non chimney leak

source: www.orionrestoration.com

Sometimes, a leak starts in a different place but finds its way to the chimney, and then visibly enters the inside of a room at the point of the chimney.

For example, your roof might have a leak through the attic vent or roof shingle at the top.  Water could get into the attic or above your ceiling and either drip to the floor or roll along the stringer (the long piece of wood that spaces out the roof trusses and runs the length of your house). If the stringer is un-level, water can travel a ways – and even wind up at the chimney. It has happened, and usually isn’t discovered until people have spent a terrible sum fixing everything else.

Another event that could happen (although I have never heard of it actually happening) is that you could get so much moisture in your attic that it could condense and roll down the stringer onto your chimney.  This could happen if there were some reason your attic was getting a lot of humidity in it – for example, if your dryer vented into the attic instead of out of a vent perhaps, or if your gas furnace were vented by B Vent but just dumped into the attic (which would be a severe carbon monoxide risk, incidentally).

 

–Need help with your chimney leak repair in Maryland, DC, or North Virginia? Call High’s!

Four Common Chimney Problems

1. Bricks cracking and falling off the chimney:

The problem is that your chimney bricks are absorbing water and then during normal freeze/thaw cycles the bricks are breaking apart and falling off. The solution is to apply a waterproofing to the outside of the chimney. Waterproofing will prevent water penetrating your chimney and the cracking and flaking of the bricks. A chimney professional will apply a waterproofing coating to the outside of the chimney that will reduce water penetration into the masonry by 99%, and it is also vapor permeable, which means it won’t trap water vapors when using the chimney. Waterproofing your chimney with a chimney liner gives an added layer of protection to this section of your home.

2. Water stains on the mantel or the face of the fireplace:

One possible problem could be water entering through cracks in the crown. To fix this we would, depending on the damage, either rebuild the entire crown, or seal the crown with a crown coating and sealant.

3. Water inside the firebox:

If you notice the inside of your firebox is wet after a rain storm then the most likely cause will be an uncapped chimney or chimney with an improperly sized chimney cap. The fix should be quite simple, install a properly sized chimney cap to keep water from entering the flue.

4. Water stains on the ceiling:

If stains are developing above your fireplace on the ceiling then the most common place for water to be leaking is the flashing between the roof and your chimney. In most cases the problem can be solved by applying a chimney flashing sealant. A high quality flashing sealant is excellent for use in stopping problem leaks around the base of chimneys, stacks and vents. However, sometimes the issue is too difficult to be properly sealed, and you may have to repair your chimney leak or crack.

A professional chimney sweep is usually your best choice for repairing common chimney issues.

All About Chimney Crowns

What’s a Chimney Crown Anyway?

Your chimney crown protects your chimney from water damage entering through small cracks. Some experts believe that less than one percent of all chimneys are properly crowned. Most bricklayers simply finish off the chimney with brick mortar – this is probably due to expediency or lack of education. In either case, this ultimately leads to severe damage, especially for those who live in parts of the United States where freezing is an issue.

Why Are Chimney Crowns Important?

Without a proper chimney crown- or if you have a cracked one, rain water seeps into the bricks and mortar of your chimney structure. In the winter this water constantly freezes and thaws. When water freezes, it expands by about ten percent turning small cracks into large cracks and causing “spaulling” (peeling) of the bricks, and deterioration of the mortar.

Chimney-Crown-Finished

Even minute amounts of water can result in brick flaking, mortar deterioration, and unsightly salt deposits on your chimney. Without a good crown that has been sealed your chimney does not have any protection. Eventually, the bricks and mortar break up enough that the chimney is no longer structurally sound.

How To Tell If Your Chimney Crown Is Properly Built

A properly built chimney crown has a slope to protect your chimney from water damage. The crown will slope from the flue liner at a certain distance from and past the walls in order to protect the chimney. An overhang will keep water from dripping off of the chimney crown and onto the face of your chimney.

If your crown is not built like this, as important as chimney waterproofing is to everyone, it’s even more important to you! While checking your crown, be sure your bricks are not soaking up water, be sure your flashing at the roof-line is sealed, and that you have a chimney cover!

Seal That Crown!

While your entire chimney needs to be protected, your crown is particularly vulnerable. For protection from freezing and thawing, the crown must be sealed with a durable sealer, such as Crown Coat by Saver Systems or Flexible Crown by WeatherTite Industries.

Call your chimney sweep to have your chimney inspected for water damage. What might appear to be minuscule damage may only require one more season of wet weather to ruin your chimney. Modern crown materials allow for quick, affordable repairs while your cracks are still only small cracks. It is a hard fact that paying for a new crown and set of chimney caps and seal now is much less expensive or messy than paying for a whole new chimney later!