Category Archives: Chimney Liners

Lining and relining chimneys is an important service that many chimney service companies provide. Chimney liners reduce the chance of fire, improve efficiency, and stop the flow of noxious gasses such as carbon monoxide. That said, many homeowners need to conduct research to ensure a chimney is not relined that doesn’t need it and to ensure that they get their chimney lined the right way.

At High’s, we’ve replaced and installed thousands of chimney liners, and we’ve written several articles to share our experience with you so that you can better understand this important topic.

If you happen to be in Maryland, Virginia, or Washington DC and think you need a chimney relined, we’re here to help.

Is Chimney Repair Covered by Homeowners Insurance?

Is Chimney Repair Covered by Homeowner’s Insurance?

Short Answer: It Depends. Here are some answers to questions we regularly encounter, and hopefully, a lot of insight into the whole subject of “insurance coverage and chimney repair.” Continue reading

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 Liners: Description, Types, and Importance


At High’s Chimney we’ve found that chimney liners are perhaps the most under-appreciated part of the fireplace and flue system. That’s why we decided to write a little piece giving an overview of their function and importance.

What is a Chimney Liner

A chimney exists to carry dangerous gasses out of the home, and it needs to do so without getting over-heated. A chimney liner creates a barrier between the flue and the walls of the chimney, and its purpose is to insulate and protect the chimney. According to the Chimney Safety Institute of America, a chimney liner is defined as:

“A clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion.”

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Chimney Terminology: Chimney or Flue or Vent?

Chimneys, Vents, Connectors & Flues: a terminology guide

Chimney terminology can be confusing. Whether you’re doing online research or talking to a chimney and vent professional, a sound understanding of associated terminology can help you ensure your chimneys and vents provide optimal protection for your home. This guide will help you understand chimneys, vents, connectors and flues.

A chimney is a passage to carry the products of combustion outdoors. Chimneys are made to be able to vent all types of fuel: gas, oil, and solid. Chimneys may pass through the house (including the living space), be outside of the house in a chase (a surrounding to protect the chimney against weather), or be outdoors. Chimneys may be masonry or factory built. Factory built chimneys are generally stainless steel, and may be covered by a chase (for protection or decoration), or left as is.

While chimneys vent fuel, they are not considered “vents”.

Understanding Vents

Vents are used to carry the product of combustion for lower temperature appliances (those using gas or oil) outdoors. Vents may pass through the house, or run outside of the house, so long as they are protected from the elements. Vents need a degree of temperature protection, otherwise their low temperature combustion products may be too cool to properly vent. This could cause a dangerous amount of flammable byproducts to collect in your vent.

The top of a vent must be exposed to the outside to allow the byproducts to be released, but such exposure will not cause problems given the rest of the vent is properly set up and protected. Sometimes a vent fan is installed to help push (or pull) low temperature byproducts from the vent.

Vents are always factory built. They are not chimneys, as they cannot handle the high temperature of wood combustion. Some vents, however, may run through a chimney, given that anything else venting through the chimney is contained in a separate flue.

Understanding Connectors

Connectors are also known as “stovepipes” or “smokepipes”. They pass from an appliance to a vent or chimney. There are a variety of connectors available, and the type of connector needed depends on the type of fuel that needs to be vented.

Understanding Flues

A flue is simply a passage for conveying exhaust gases from an appliance to the outdoors. A flue may be a duct, pipe, vent, or chimney. An unlined chimney is technically a flue, even though an unlined chimney is a fire hazard. This can cause confusion, as many view flues not just as a passage for venting, but as a safe passage for venting.

Understanding Chimney Liners

There’s a misconception that masonry chimneys are simply made of brick. This isn’t true. The uneven and porous surface of brick provides a space for combustion byproducts to accumulate. This is a major fire hazard. Rather, chimneys are lined, so the smoke passes over a smooth surface that helps prevent excessive accumulation of combustion byproducts and minimizes the chance of fire. Chimney liners are also called “chimney flue liners”. The terms are largely used interchangeably.

Traditionally, chimneys were lined by fireclay flue tile. This special tile is carefully laid inside chimneys to provide no ridges or spots for accumulation; the tile is finished to a smooth, nonporous surface. This classic chimney liner can be difficult to fix should tiles become damaged deep inside the chimney.

The most popular modern liner is stainless steel. These liners can be inserted in unlined or tile lined chimneys. They are inexpensive compared to tile liner, easy to install, and easy to replace should any damage occur.

With a proper understanding of the differences between chimneys, vents, connectors, flue and chimney liners, you can have a better understanding of your chimneys and vents, and can more easily discuss any problems that arise and how to fix them.

This guide is only the beginning, as there are many other aspects of chimneys and vents to consider. Next week we will discuss in detail different types of connectors, vents and chimneys to give a more in depth knowledge of what the difference between various types are.

Masonry Chimney Repair & Relining

Masonry Chimney Repair & Relining

The Washington DC area has a rich history of architectural styles. From brick farmhouses in Fairfax to Victorian row houses in Georgetown, Washington DC has preserved much of its architectural history. These homes have weathered decades (or centuries) of use, remodels and updates while still possessing an undeniable charm. The sturdy construction of these historical buildings plays a large part in their continued existence, but constant monitoring and maintenance is what keeps these charming homes instead of quaint historical exhibits.

Routine inspections and preventative maintenance can help keep houses old and new running smoothly. For many components of your home this can be a simple process. For example, wear around your windows and persnickety plumbing are easy to spot. For other parts of your home, such as your chimney, a little effort is required.

Chimney Masonry Maintenance

Most responsible home owners ensure they have a proper flue with optimal draft and that the major components of the fireplace are functioning properly. This diligence causes the illusion of security; so long as no major problems occur, their chimney must be healthy. In reality, without a watchful eye, water damage can compromise the integrity and safety of your chimney long before you notice the problem. While the rest of your roof is protected from the elements, your chimney is exposed to the worst of Mother Nature.

While the brick itself generally fares well against such odds, without water proofing the mortar is heavily susceptible to water damage. Specifically, mortar absorbs moisture. As the temperature changes, freezing and thawing cycles cause this water to expand and contract, which will cause cracking. This damage is often subtle, and by the time you notice crumbling mortar you will likely need masonry chimney repair. As it progresses the mortar will erode out from between the bricks, causing their weight to shift. This causes additional stress on the masonry, and exacerbates any existing cracks or stress points. Without proper care, mortar erosion will cause an unsafe and unsightly chimney that will need major masonry chimney repair. At this point a chimney professional will need to repoint the brick, and apply a waterproof sealant to prevent future water damage.

Masonry Chimney Relining

Chimneys suffering from masonry damage can let an excessive amount of water into your chimney’s interior. If you actively use your chimney as a vent, this can affect your flue, fireplace, and any appliances that vent into the chimney. For example, rain running down a used flue will mix with creosote and other deposits, causing a corrosive solution that can deteriorate your flue. This corrosive solution can drip down onto fireplace hardware, such as dampers, and rust them. Even if your chimney is perfectly clean, rain water will settle into any joints or cracks in your flue, where temperature changes will cause it to expand or contract, causing damage. This will cause a premature need for chimney relining.

Even if you don’t use your chimney as a vent, masonry chimney repair is important. Crumbling mortar allows moisture to permeate to the interior of a chimney. Inside the chimney, it will run down the joints in the masonry, leaking into cracks. This compromises the structural integrity of your chimney, which is never safe. Relining and repointing the interior of a masonry chimney is an expensive and time consuming process. To be able to work in such tight spaces, it’s often necessary to punch holes in the chimney to be able to ensure the proper work has been done.

If you have questions about masonry chimney repair or suspect you might need masonry chimney relining, contact us at High’s Chimney. We want your home to be a healthy, safe place to live. We offer free consultations on masonry repair, and our real time online scheduling service makes it easy for you to pick a time that works with your schedule. Being proactive about problems as they arise, such as masonry chimney repair and relining, is the best way to ensure your home remains a safe and stylish place for you and your loved ones to enjoy for years to come.

Types of Chimney Liners

About Chimney relining: Types of Chimney Liners

No matter what sort of chimney lining you have, in time it will need to be maintained or relined. Understanding the three major types of chimney liners will help you discuss with a trusted professional the best way to line your chimney and keep your home safe and sound.

Clay Tile Chimney Liner

Clay Tiles have been a historical favorite for lining chimneys. As such, most older homes have clay tile liner. These were popular for a variety of reasons, the most important being that clay tile insulation with properly finished mortar joints can withstand most types of smoke and can last up to 50 years.

In today’s world, however, these tiles are not the perennial favorite. Studies show that during a chimney fire, even the most well finished mortar joints are likely to crack, and usually break apart. Any crack in your chimney lining makes it more likely that the fire could spread to the rest of the building.

Clay Tile Chimney Liner

Clay Tile Chimney Liner

Additionally, repairing or relining a chimney with clay tile is a very difficult task. Punching holes in the chimney to ensure the tiles are aligned and joined correctly is often necessary, and such effort is costly. For this reason, when most home owners notice cracks or problems with their clay tile chimney liner, they transition to a different liner entirely.

Cast in Place Chimney Liner

Cast in place liners were created around 60 years ago. While initially they were highly-regarded, over time their popularity has decreased due to a high likelihood of cracks.

One benefit of the cast-in-place chimney liner is the insulative properties of the material. The insulation helps keep heat from leaking from the chimney, and higher temperatures in the chimney helps ensure creosote, soot and combustive gases are more fully consumed, which means less accumulation inside your chimney, and fewer emissions from your chimney.

The downside to this chimney liner is again cost. Installing the liner can be expensive, and if you have any bends in your chimney, the price is just going to go up. A professional will also need to determine if any existing chimney liners need to be removed prior to chimney relining. Also, as cracking develops, the process of relining is expensive and time consuming.

Metal Chimney Liner

Relining Chimney with Metal Liner

Lining Chimney with Metal Liner

Metal liners are by far the current favorite of the construction world. They come in a vast array or shapes and sizes, and can either be rigid of flexible. Installation and parts are generally inexpensive, and with proper maintenance metal liners often outlast the house. Also, as appliances within your home change and chimney liners adapt to meet these changes, replacing your chimney liner with an up to date metal liner is an easy and logical process.

Reasons for Relining
The largest reason for chimney relining is improper liner sizing. Improperly sized lining can lead to soot and creosote deposits and improper draft, both of which are safety hazards. Proper chimney lining size is a difficult variable to determine, so if you have any questions about the best size chimney lining for your home, contact a chimney professional.

The second largest cause of chimney relining is cracks and breaches in the lining itself, which is a large fire hazard. At the first sign of cracks or damage, call in a professional to ensure your home is safe. Remember, even if you stop using your fireplace, other appliances may vent into your chimney exposing you to potential danger.

This Old Chimney Part 1

Common Issues Found In the Chimneys of Old Houses

Old Masonry Chimney

An Old Masonry Chimney

If you own an old house or at least an older house, you will have different considerations than those who own newer homes. Newer homes are more likely to be built following modern codes and with materials that conform to modern published standards.

This means newer homes are more likely to be safe. This doesn’t necessarily mean that your old home is unsafe, however. You just have to know what you’re looking for and bring certain conditions up to proper safety standards. This article will guide you through the considerations specific to your chimney and educate you about your options.

Types of Fireplaces in Older Homes

By “old” we mean houses more than 60 years old. The fireplaces and chimneys in older homes are almost certainly masonry based. The metal, factory built hearth systems are found mostly in houses built after the 1950s. Most masonry chimneys are made with bricks, though there are also block chimneys.

Why You need To Improve Your Old Chimney Before Using It

Lack of lining is one of the most common issues that we see in older chimneys. As a flat statement, any chimney that is not lined should not be used for any purpose. You may say, “Well, it’s been there for 80 years, so why change it now?” and that’s a reasonable question. In some cases the answer is that nothing has changed – the situation has always gotten worse! The reason why your chimney’s condition has gotten worse is because most things wear out over time and a chimney is certainly no exception to that rule.

Additionally, the fact that furnaces and stoves of 2011 require a more capable chimney to support them makes unimproved, older chimneys more or less obsolete.

Why Chimney Linings Are So Important

Installing Chimney Lining

Installing Flexible Chimney Lining

Here are a few reasons why chimney linings are so important:

  • Unlined chimneys have bad draft characteristics. These bad draft characteristics cause the appliances they serve to work less than optimally.
  • Unlined Chimneys may leak noxious gases into the living space.
  • If used for gas, modern appliances have such low-temperature flue gasses that they produce huge amounts of condensation. With an unlined chimney, the condensation is allowed to adhere to the actual masonry. This ruins wall paper in the house, and the freeze-thaw cycles in the winter slowly demolish the masonry chimney.
  • If the chimney is used for wood burning, the condensation can also help form tar and creosote, which is flammable. In this case, they pose an unnecessary fire danger.
  • When you make a change to the construction of a structure, the system must come up to building code standards. So if you have a new furnace or boiler, a woodstove or insert, the chimney must be lined at that time.
  • You may find yourself without insurance if you make changes without improving the chimney. Check with your insurance company if you intend to disregard the advice here or consult a certified chimney sweep.

Basically, have your chimney lined as soon as possible.

Block Chimneys in Old Houses

Block chimneys do work, but as a general statement they are less than desirable. Block chimneys are really meant to be surrounded with bricks. They are more subject to cracking, leaning and leaking; most any problem you can imagine. As a general statement, if you have a block chimney built right against the house it’s probably not legal and if you have a wood-frame house you probably ought to just tear it down. However, if you can build brick around all four sides, unlikely in most situations, you can get the clearance to combustibles called for in the codes, the chimney can be serviceable.

Old Brick and Mortar Chimneys

Old brick chimneys have their own set of problems. Fortunately, older bricks are often actually better than newer bricks. It’s the way they were fired that makes the biggest difference. That’s why you see some houses from the 1800s or even 1700s where the bricks are still in great condition. Yet you’ve also probably seen modern houses with the faces of the bricks popping off. So if you have an old house, you probably have pretty good bricks!

Shifting Ground and your Old Chimney

The ground is always moving a little bit. Fortunately houses are actually a bit elastic, or at least allow enough give that they don’t split in half when the ground heaves an inch. But over time, those stresses can break bricks. If you have that problem in your chimney or walls of the house, it’s probably visible. Broken bricks are just a fact of life sometimes. You might need to replace them eventually.

Old Masonry Chimney Degradation Due to Weather

Sun, wind and rain are hard on any masonry work, especially the mortar. There are so many different types of mortar and concoctions of mortar cement that there’s no guessing how long your mortar is supposed to last, but suffice to say 60 years on a chimney is a long time.

When the mortar wears out it’s either time to rebuild or re-point. Re-pointing is the process of grinding out about an inch of the old and broken up mortar and putting in new mortar without removing the bricks. Unless your chimney is quite large, it may be just as easy to dismantle it and rebuild using the same bricks.

Waterproofing Your Old Chimney

One thing about those great old bricks is that they soak up water from the rain. On the sunny or windy side of the house that’s probably not a problem because they dry quickly. However, in shady areas the bricks can hold water and in the winter that water can freeze. This type of problem is usually visible. There are good water-proofing materials such as ChimneySaver by Saver Systems which do not block the pores of the masonry. Whatever you do, don’t use silicone, such as Thompson’s, because silicone blocks the pores and it has a shorter life due to UV light breaking down the silicone.

Your Old Chimney Crown (Or Lack Thereof?)

There’s another aspect of the chimney that’s almost always lacking on older homes, and that’s the chimney crown. The crown is the cement part on top of the chimney that keeps the rain from going into the structure below. The crown catches more sun, wind and rain than all the rest of the chimney, and it is usually not as thick as a brick. Crowns are almost always cracked. I can’t think of one crown I ever seen that wasn’t cracked. If the crown is bad enough, it needs to be taken off and re-laid. If it is cracked but still structurally sound there are good materials to coat the crown, which will save money.

Regardless, you should have the crown coated with CrownCoat by Saver Systems or some similar product. If you put up a brand new crown, coat it so it doesn’t break up again.

How to Deal with Lack of Clearance to Combustibles

Clearances to combustibles is something they didn’t worry about in the old days. It is quite common to see wood beams or 2x4s right against the masonry of a chimney. When there are fires in old homes, it’s also common to find that some of this wood ignited. Oddly enough, the process of pyrolization takes place over many, many years. The unscientific definition of that is that the ignition temperature of wood gets lower over time. In other words, it takes less heat to catch it on fire 50 or 100 years later than when it was new.

Chimney Insulation

The way to deal with that is to make sure you have a liner installed to zero-clearance (insulated). The only alternative is to tear out the walls and cut away the wood. Practically speaking, nobody is going to do that, and even if you do, there’s no guarantee you’d get it far enough away. Take a look in the attic and remove wood you find against the chimney up there. That’s not so hard to do.

Removing Debris and Blockages From Your Chimney

At the base of an old heater flue, usually in the basement, there can be all kinds of debris. Sticks and leaves, dead birds, or maybe a lot of soot. Old oil furnaces may have released sulfuric acid in the chimney for years and worn the chimney out from the inside. Aside from that though, the bases are often just blocked by debris. Just be sure to have a chimney sweep come out to make sure it’s open. If you have a flue that was converted from oil to gas, you would be venting carbon monoxide into the house. Be sure to have this checked, and especially if you or your family have a lot of colds or headaches because this could very well be carbon monoxide poisoning.

With regards to that debris in the chimney, many older homes are “finer homes” that are surround by trees or perhaps in a semi-rural setting with lots of animals and leaves. That being said, a chimney chase cover is smart to prevent debris from building up as well as protection from harsh weather conditions.

Read Part 2 for more on old chimney problems!

Benefits Of A Stainless Steel Chimney Liner

Chimney liners are a vital element in the operation of your fireplace or wood stove. And when the liner has deteriorated, cracked or aged beyond its limit you have a choice of materials for the replacement chimney liner. Clay tile is a traditional choice for the liner, although you can also choose cement or aluminum. Stainless steel chimney liners are a popular and durable choice that delivers various benefits.

Long Lasting

Because stainless steel is corrosion resistant you can expect this liner to last for years virtually problem free. And the complete seal applied to the liner keeps nasty emissions away from your masonry, allowing them to last longer and cutting down on required repairs.

Affordable

A stainless steel chimney liner an affordable alternative to most traditional chimney liners. Easier to install than clay tile liners, the initial installation of stainless steel liners is less expensive. Also, chimney sweeps have an easier time cleaning this type of liner thanks to the round shape. No square corners to catch deposits of creosote makes for a faster, more effective clean. In the end, this should cost you less.

Sealed and Smooth

Aged clay tile chimney liners will crack and split, which allows noxious fumes to leak into your home. With a stainless steel liner you will effectively seal those cracks and drastically reduce the chance of them happening ever again.

Added Insulation

Insulation can be fitted around the stainless steel liner or stuffed between the liner and the chimney walls. This insulation cuts down on creosote build up by keeping the air hot all the way up the chimney. It also helps to reduce the cold air draft that could come down the chimney when the fireplace or wood stove is not in use.

Replacing your existing liner with a new stainless steel chimney liner is a wise choice, offering your home all of these benefits and not to mention, a whole lot more.

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 Your Chimney Lining

Lining your Chimney

Why are so many people having their chimneys relined these days? As cold weather approaches and you fire up your heating system, wood stove or fireplace, are you thinking about the inside of your chimney system?  In a perfect world, the inside of a chimney is something you’d never have to think about. Unfortunately the world isn’t perfect and many masonry chimneys aren’t either! Let’s discuss what can go wrong inside of a chimney and how chimney liners figure into it.

A chimney’s purpose is to carry the flue gases out of the home, and it needs to do this without getting over-heated. The problems with the inside of chimneys falls into two general categories: the problems that cause flue gasses to back into a house (smoke or carbon monoxide) and the problems that can cause house fires.

Most masonry chimneys are lined with fireclay tiles. This material has been used for 100 years and was a huge improvement to unlined chimneys of the 1800’s and before. In fact they served well enough until the 1970’s. Here’s what happened.
chimney lining

As people became conscious of the cost of heating, they started to put glass doors on the front of their fireplaces. This changed the fuel-air ration that had existed for eons. Suddenly masonry fireplaces that had never had problems before got full of soot and creosote in a matter of months.

Fireplace inserts caused the same problems, only even more so. The stoves were engineered for flue openings of six or eight inches round but were venting into chimneys built for open fireplaces. And fuel-air ratio was now so low that many chimneys collected a thick, wet, gooey tar. In some cases, chimneys were catching on fire within weeks after the stoves were installed!

Obviously the same was true for freestanding woodstoves.

And what about central heat flues, that is gas and oil? Well, those appliances changed too: they became much more efficient. The problem there isn’t creosote, as these fuels burn much cleaner. But it takes a certain amount of heat loss in the chimney to take the fumes up the flue and it wasn’t there anymore.

Three bad things happened to the masonry chimneys:

  1. More heat was delivered into the home and the flues didn’t have enough heat to carry the gasses up and out!
  2. The water in the exhaust condensed in the flues (instead of in the atmosphere). The inside of gas heaters in particular got very wet. Very, very wet indeed: so wet that they could freeze in the winter and block up, or so wet the wall paper inside the house was peeling where the chimney passed by. So wet that the freezing and thawing deteriorated the outside bricks themselves!
  3. And carbon monoxide levels in the houses skyrocketed! Tens of thousands of people a year are affected by CO poisoning and many don’t even realize it. They just don’t feel so great; lethargic or as if they have a cold. And of course there are even deaths… it’s a bad situation.
    • For reasons more technical than this article will cover, a properly sized liner will extend the appliance life and its heating efficiency. This is true for both central heaters or wood burning appliances.
    • For gas flues you can use aluminum but it often doesn’t have a very long life with modern appliances. The best material for lining a chimney, whether gas, oil or solid fuel, is stainless steel. #316 is a very good alloy for chimney lining and is readily available.
    • The liner must be properly sized to the appliance for it to work properly. Either too big or too small is not good enough. Don’t get this wrong.
    • There are three systems in your home that can kill you: electrical, plumbing and venting.  Unless you really know what you’re doing, unless you’re the kind of do-it-yourselfer who’d dig up his own sewerage system etc. don’t try to do it yourself. While anybody who can work with tools can theoretically do anything, there are enough things to go wrong with a venting system that this isn’t something you should tackle yourself. Hire a professional.

    Add to this that in most cases tile chimneys are not particularly well sealed in the first place, just because that’s the way they’re built. Also, many homes now operated under “negative pressure.” That means that our airtight windows and doors, our weather stripping, and our fans in the house all conspire to prevent good draft in chimneys. All of these factors combine to create the need for smaller, positively sealed venting systems.

    This is where chimney liners come in. The info above pretty well describes why you need a modern chimney liner. Lining your chimney with a good stainless steel liner will pay you and your family dividends both in dollars and in vastly increased safety.  Make it your next home improvement!