Posts made in March 2011

This Old Chimney Part 2

Problems With Older Chimneys Continued

In this two part series, we’re discussing typical problems that owners of old homes have with their chimneys. This Old Chimney Part 1 begins the conversation that we’re continuing this week.

Chimney Smoking Issues

Fix a Fireplace Smoking Problem

Smoke Stains on a Fireplace

If you see smoke on the face of the fireplace above the lintel (The thick metal bar that holds the bricks across top of the opening,) it is a sign that the chimney is smoking. This is fairly common issue with old chimneys. There are a few reasons why chimney airflow problems occur.

Older houses are usually not very air tight; in fact they’re more likely to be drafty. But maybe the house has new windows and doors, the walls are tight etc. so maybe the house can’t breathe. This can cause a change in air pressure that hurts the drafting process that causes smoke and gasses to rise up the chimney. It’s unlikely that an old house can be sealed up so effectively, but it is a possibility.

More likely is that the flue is either blocked or was never properly sized. Proper sizing means that there is a relationship between the size of the flue and the opening of the fireplace. Think of this in a ridiculous extreme: if you had a flue the size of a soda straw you would not expect a fireplace to draft properly. There are ratios that work or don’t work. That ratio can be changed with a smoke guard. These are commonly available from hearth shops and chimney sweeps. Glass doors usually will help a chimney smoking problem as well.

Gaps in the Chimney Bricks: Fixing Fireplace Air Leaks

Fireplace Air Leaks

Gaps in the Bricks Causing Air Leaks

There’s often a space between the bricks on the front of the fireplace (the wall, or the “face bricks”) and the structure of the fireplace itself. Sometimes that gap is on the floor by the hearth (in front of the wood burning fireplace too.) Not good. These gaps are probably caused by the old house settling over time.

You should inspect the fireplace carefully with a bright light to see if any wood is visible. If so, stop all action and call in a professional CSIA Certified Chimney Sweep. Wood in this area can cause fires quite easily and is a real safety hazard. If you don’t see anything, then get a chimney sweep to pack the gap with ceramic wool and refractory cement. Packing the hole yourself with typical cement won’t work because of the extreme temperatures in the fireplace.

Common Hearth Issues

Did you ever wonder how the hearth “stays up” that is to say: what supports all that weight? What’s under those bricks and that heavy firebox? The answer could surprise you- sometimes very little! Or sometimes, commonly found in old houses, there’s wood. Not good.

Go to the basement and look up to see what’s supporting the hearth. If you have metal I beams then great (I’d be surprised if you do.) Perhaps it’s supported on a masonry foundation, and that’s good. Or if you see cement that’s probably fine too, while it’s not clear what’s holding the cement in the air (though something obviously is) at least it’s not combustible.

But if your hearth is supported by sitting on a piece of plywood, you need to change that. More than one house has burned down because of that sort of thing.

Improving the Smoke Chamber of your Old Fireplace

Fireplace Smoke Chamber Parging

Parging the Smoke Chamber of The Fireplace

Above the damper area is the smoke chamber. This is the area where the wide fireplace funnels up to the smaller flue. The bricks are stepped in, or corbelled. That’s a rough surface, and it makes for a) less draft, b) more heat transfer though the wall c) a dirtier chimney. And modern codes say they should be parged. Parging is the practice of spreading some sort of cement over the corbelling to smooth out those square steps. This is not something you can do yourself. Somebody has to open the back of the smoke chamber (take bricks out) and reach through the hole to parge. Alternatively there are materials that can be sprayed (sort of like Gunnite, only it’s a different material.)

Call a chimney sweep and ask him if he’s able to spray or parge the inside of the smoke chamber. You may need to make a few calls to find somebody, because the work isn’t easy and it’s not fun. But it’s worth doing- the smoke chamber is usually the weakest part of the system next to the chimney itself.

If you’re lucky, that area is already parged and the parging is holding up well.

Common Old Chimney Problems

Well, that wraps up our conversation on old chimney problems. Have questions? Old home stories? Let us know in the comments section!

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!

The Difference Between Fireplaces and Fireplace Inserts

What’s the difference between Fireplaces and Fireplace Inserts?

There is a lot of confusion about these terms. After all, a “fireplace” ought to be any place you can have a fire, right? Yep, but there is a difference anyway and today I’ll lay it out for everyone.

Open Fireplace example

An Example of an Open Fireplace

 

What is a fireplace?

When folks talk about a “fireplace” they generally mean an open fireplace. This usually means an opening in the wall with a flue above it so you can have a fire indoors. The key here is that it’s open. To confuse the matter more, a lot of fireplaces have glass doors on the front. You might point out that it’s not open anymore, and you’d be right, but it’s still “a fireplace.”

Types of Fireplaces

Fireplaces can be either masonry fireplaces or factory-built fireplaces (also called prefabricated or “prefabs.)

Masonry Fireplace

A masonry fireplace is almost always built of bricks. There are some specialty types that are more exotic and use refractory materials, but 99.9% of them are made with bricks.

Factory Built Fireplace

A factory-built fireplace is a metal box with refractory bricks inside manufactured to be framed into a house, without masonry. Sometimes they are gas fireplaces, but they are often for burning wood. These are perfectly safe when installed according to the manufacturer’s instructions.

The Heatalator

There’s also sort of “an in-between” situation, commonly called the Heatalator. Heatalator is a brand name which is applied to products which are generally like it. Just as all tissues aren’t Kleenex brand, it’s pretty common to just ask for a Kleenex and everybody understands. The same is true with Heatalator. It’s a metal firebox which is built into a masonry structure. Even though it was built in a factory, this is still considered a masonry fireplace. This is because of clearance and heat transfer requirements etc. Too much information? Suffice to say Heatalators are also fireplaces.

Fireplace Inserts

regency alterra CI1250-ASo what’s a fireplace insert? In a word, it’s a stove. Either gas or wood, it’s a stove which is inserted into an open fireplace.

Fireplace inserts are almost exclusively installed into masonry fireplaces, though there are a few very special models which are listed to be installed into prefabricated fireplaces, such as the Regency Alltera CI1250.

A fireplace insert must always be installed according to the manufacturer’s instructions and listings or you’ll put your house in serious jeopardy. Following these two bits of advice will go a long way toward keeping you and your family warm and safe at the same time!

  • Insist that your stove have a properly-sized liner all the way from the top of the stove out of the top of the existing chimney. Click here for more information about chimney liners.
  • Insist on knowing that any insert you buy is listed for installation into your fireplace.