How To Insulate A Chimney Outside?

This comprehensive guide on how to insulate a chimney is a step-by-step guide on how to prevent heat loss and improve energy efficiency. A chimney is a structure that connects the flue or smoke chamber of an appliance to open air, allowing proper ventilation while preventing reverse flow. Warm heated gases need to escape your home, and venting them out through your chimney helps prevent heat loss.

Insulating around a chimney can be done using various methods, such as insulation blanket wrap, drywall facing the chimney, and insulation products like Roxul comfortboard or micore. The insulation should be applied between the room and the chimney, with doors on the fireplace opening.

For outside insulation, cover the entire stack of bricks with a layer of rigid insulation (rockwool or expanded polystyrene). A “false” or hollow chase should be built up the left side of the chimney and match the right side so both left and right sides have a 45-degree angle. Some types of spray foam can be used on exterior chimney walls, but always place a fireproof material over the insulation and leave plenty of room for an air leak.

Improving energy efficiency and reducing heating costs can be achieved by using standard insulated wood framed walls to insulate the conditioned space from the vented faux-chimney. On an exterior chase, the outer three walls typically should be weatherized, including air sealing such as foam or caulk, insulation, and rigid insulation.

In summary, insulating a chimney can significantly improve energy efficiency and reduce heating costs. By following these steps, homeowners can save money and improve their home’s overall comfort and energy efficiency.

Can insulation touch a chimney?

Most chimney manufacturers require a 2-inch air space between the chimney and flammable material, including framing, which should not be filled with insulation. The 2″ clearance between flues and combustibles is enshrined in code, and metal air-barriers can pass through walls, ceilings, and roof decks but still need the 2″ clearance. Rock-wool batting is preferable to fiberglass in studs, joists, and rafter bays, while foam with just the 2″ clearance is considered insane.

When going through a foam layer, use 3″ or more rock wool between the flue’s 2″ clearance zone and the foam. Polyiso and polyurethane have an ignition temperature 100F hotter than XPS or EPS, and do not melt when fully engulfed and burning on its own.

Can you insulate around a brick chimney?

The combustion of fuel in a domestic setting generates high levels of heat, which must be dissipated in order to maintain a comfortable internal environment. Spray foam insulation or injection foam can serve to prevent future issues by acting as a barrier. It is also worth noting that traditional insulation materials, such as fiberglass and cellulose, can potentially lead to issues. This is because they may prevent flammable materials from being adequately separated from the heat generated by the fireplace and chimney.

How do I stop cold air coming down my chimney?

To fix cold air problems in a fireplace, close the damper, close glass doors, and have a professional install fireplace doors. Many people expect cold drafts coming out of the fireplace, but this is a common issue. Down draft chimney issues are the second most common complaint of fireplaces, but they should be tolerated. Cold air from the fireplace is controllable, and with a little investigation, your hearth room can be cozy again.

When there isn’t a fire in the fireplace, the fireplace and chimney act as another opening to the outside doors, causing both indoor and cold outside air to flow in the direction of high-pressure moving to low-pressure.

How to fix a drafty chimney?

To stop a draft from a fireplace, first identify the source of the draft. Check the chimney, damper, hearth, chimney chase, chimney balloon, chimney draft stopper, and weatherstripping. Drafts are essential for drawing smoke and harmful particles out of the chimney or flue, keeping the home safe from fire. However, they can also send cold winds when the fireplace is not in use. To address this issue, install a chimney balloon, use a chimney draft stopper, and use weatherstripping.

Does the outside of a brick chimney get hot?

It is imperative that a minimum clearance of 1-4 inches is maintained for chimneys, given the potential for the exterior surfaces to reach elevated temperatures. In the event that a chimney contains multiple flues, it is imperative that a wythe be employed to separate them. It is imperative that flue offsets do not exceed the center of the upper portion or the lower flue’s wall in order to prevent changes in direction. These guidelines are outlined in NFPA 211, section 7. 1. 2.

Does exterior chimney pipe need to be insulated?

An oil or gas furnace produces lower temperatures due to heat extraction for heating the house, resulting in condensation when the exhaust gases cool in the flue area. Insulating an oil or gas flue liner can reduce corrosive condensation by keeping the gases warmer and improving the draft. If venting into a chimney with a clay liner, it is likely too large, cooling the gases and deteriorating the clay liner and mortar.

To install an insulated stainless steel chimney liner, either wrap the liner with insulation before inserting it into the flue or install the liner first and then add pour-down insulation. Selecting the proper diameter liner is crucial, which can be determined by BTUs, the cross-sectional area of the fireplace opening, or by matching the exhaust size of the wood insert or stove. This will help maintain the efficiency of the draft and prevent the deterioration of the clay liner and mortar.

How to insulate an outside chimney?

Spray foam should not be used around a fireplace due to its flammability and increased fire risk. Instead, some types of spray foam can be used on exterior chimney walls, but it is essential to use fireproof material over the insulation and create an air barrier between the chimney and fireplace wall. Closing the damper when the fireplace is not in use can also help reduce drafts and prevent cold air from entering the home.

Insulating your fireplace is a simple way to make your family more comfortable during winter. Trust One Hour Heating and Air Conditioning technicians for expert maintenance and emergency repairs. Request an appointment or call 893-3523 for more information.

How do I make my chimney less drafty?

Dampers in your fireplace can cause drafts and other issues when not in use. They should be tightly closed during non-use to prevent warping or rusting, which can lead to cold air infiltration. Replacing or repairing dampers or adding a top-sealing damper can resolve these issues. The size of your chimney is crucial for the fireplace’s function, and improper size can cause drafts, especially when transitioning from wood-burning to gas. Incorrect liner size and insulation can also cause drafts.

Additionally, chimney size problems can lead to creosote deposits, necessitating frequent cleanings. A small chimney increases the risk of a chimney fire, so it’s essential to keep the chimney size appropriate for the fireplace’s size.

Do masonry chimneys need to be lined?

The National Fire Code mandates that chimneys be lined with brick, clay, or steel. Most homes built in the past 50 years have a clay liner for wood-burning appliances, while older ones may have clay or brick. These liners are typically 8 inches by 8 inches or 8 inches by 12 inches, which is an acceptable area for drafting a fireplace. A round liner can cut the draft area in half, requiring small fires unless smoke is coming back into the house. Steel liners may require 5 or 10 minutes to warm the flue before lighting a fire.

The fire code requires chimneys to be repaired or replaced if they constitute a fire hazard. An inspector may identify a hairline crack in a clay tile liner and suggest a $2000 to $3000 steel liner, often if their company installs these liners. If the flue is not severely damaged, a new liner may be necessary.

Some common times when a steel liner is recommended include installing a wood-burning insert inside a fireplace or a free-standing wood stove, ensuring smoke is not coming back into the house from the chimney, or if a chimney fire has not been resolved rapidly and caused extensive damage to the chimney interior.

Does an outdoor fireplace need a chimney liner?

Chimney liners are essential for all areas, including terra-cotta clay flue, stainless steel flue liner, and heat shield flue lining. Unlined brick or block chimneys should not be used to vent heating appliances or fireplaces. Local jurisdictions may require specific flue liners, and stainless steel flue liners may be required by building code officials.

If your current chimney flue has cracks or missing mortar joints, it is considered unusable. Cracks can occur from chimney fires, home settling, or excess moisture in the flue. It is crucial to fix the damaged flue immediately to prevent carbon monoxide or creosote leakage. Regular chimney inspections are recommended to ensure safety. Installing a stainless steel chimney liner is the easiest solution to repair the chimney flue without requiring a new chimney and flue.

Condensation and moisture are signs of a chimney liner issue, as excess condensation inside a clay flue can cause mortar joints to wash away over time. Condensation is commonly caused by gas and oil-burning appliances venting in the chimney.

How do I stop cold air from coming through my chimney?

The fireplace damper is a crucial defense against cold air entering your home during non-burning fires. It should close tightly, blocking all air above it. If damaged, cold air can pass through. Some homeowners add a top-sealing damper at the top of the chimney for double protection. A chimney balloon or plug can also be used to block cold air from entering your fireplace. These devices are placed above the throat damper and inflated to prevent air from coming down. They are designed for non-burning fires and automatically deflate when lit.