Read about the factors on how to fix a furnace flue. You will probably have to disconnect the pipe at a joint in the attic. Pitch the flue pipe up toward the chimney. Chimneyâs minimum height above the roof will depend on its positioning / location at the penetration point, distance to any structure, roof slope, etc. Single-wall sheetmetal flue pipes are joined without sealants. The furnace flue will usually be located on the top or the rear of the furnace. Thanks for your input. What If Black Holes Are Actually Fuzzballs? You will probably have to pull the old pipe down, not up. This might include sealing: Where the flue pipe it fitted to the stove. To do this: This furnace / water heater vent pipe must continue through the roof and terminate above it. Gaps that appear between the cast iron panels of your stove. Use this smooth consistency cement to bond and seal metal to metal or metal to masonry joints less than 1/8â³. Q & A. If the furnace is running continuously, then it may face trouble. Because the pipe gets hot, building codes usually require 1 inch of clearance from metal flues (2 inches from masonry chimneys) to any combustible material, including insulation. Gear-obsessed editors choose every product we review. Cover open soffits. My pipes (single wall) had gaps where the seems where bent together. Now, you must form an insulation dam to prevent insulation from contacting the flue pipe. I used furnace cement where the last section of stove pipe fits into the pass through in the wall as well. It typically runs from the furnace to a chimney. Here's what to look for. That depends on whether you have a standard efficiency or a high efficiency furnace. Cut the tip off your high temperature RTV silicone caulk tube with a knife. Replace and secure the cap tightly to the end of the flue pipe. Apply it to the surface with a trowel or putty knife at a thickness of 1/8" to 1/4". I thought the vent pipe had to be rated. Inject the silicone caulk into the gap between the vent and the side of the house or foundation. How to Seal Gap Around Water Heater Vent Pipe. Where an external air supply pipe is fitted to the stove. Drive the screw slowly into the stove pipe. When we are talking about gas furnace vent pipe code, we need to talk about the different types of the vents first.After all, you want to keep your family safe from harm. Is this still true or is this new kind of vent pipe ok to use now? Iâve been running into a lot of furnace vents that are using the bendable corrigated vent pipe like you would use on a dryer vent. We may earn commission if you buy from a link. Thatâs because the combustion byproducts are in a gaseous form, so the gases can float up through the flue pipe and out of your roof. Seal the gap between the flue and metal flashing with a high-temperature caulk. Step 2. 2 Cut the tip of a caulk tube with a utility knife. After trimming your pipe, use black furnace cement to seal between each piece and three sheet metal screws at each joint. I also used silicon sealant to close a pretty big gap in the clean out at the base of the chimney. If your furnace has an AFUE rating below 90 percent, it will most likely have a flue pipe that goes up through your roof. How we test gear. Step 3. Flue pipes are often insulated. Ensure that the stove lid and collar, as well as the flue pipe, is protected before you apply the new fire cement. Cut the tip of a caulk tube with a utility knife. These gaps should be sealed with lightweight aluminum flashing and special high-temperature (heat-resistant) caulk. Because the pipe gets hot, building codes usually require 1 inch of clearance from metal flues (2 inches from masonry chimneys) to any combustible material, including insulation. Where roof flashing meets the flue pipe. ... that spray foam needs to be removed, and b) you need to schedule a regular chimney inspection on top of a furnace/water heater inspection done by an HVAC contractor to make sure all of your equipment is working properly. 10.3 oz. The self-tapping screw will cut its way through the sheet metal. Before you push the insulation back into place, build a metal dam to keep it away from the pipe. Fiberglass ducts require an aluminum foil tape, while sheetmetal ducts are sealed with metal-foil tape, professional-grade duct tape or mesh-reinforced mastic. The gases it exhausts are hot and moisture-laden. First, youâll need to make sure the chimney is as clean as possible, removing any lingering debris, insects, or old soot. Furnace Cement Tub in Black RUTLAND Furnace Cement is premixed and ready RUTLAND Furnace Cement is premixed and ready to use, making it one of the easiest cements to apply. Don't try to remedy the problem yourself. Then, attach the pipe to the stove and chimney pipe⦠Most of the remaining pipe will be hidden as it passes through your home, though it may be visible in the attic. Heating and Cooling: Top 5 Energy Saving (and Bill Cutting) Tips, Homeowners Clinic: Replace a Stubborn Sink Drain, Banish Water From Your Crawlspace, Neutralize Sink Disposal Odors. They are not sealed to the same extent that ducts are. You would core a hole 1/4 to 1/2 inch bigger than the outer diameter of the pipe. The joint is fastened with three sheetmetal screws. The Best Outdoor Gifts for Every Type of Adventure, This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. Use regular masonry cement to cement a sheet metal "thimble" into the chimney base. Then build a metal dam to keep insulation from touching the flue pipe. Sheetmetal flue pipes, on the other hand, carry combustion gases from the furnace or the boiler to the chimney. 48 Posts . Using high-heat silicone caulk, completely seal the joint by squeezing the caulk out in a neat bead and then smoothing it over. Popular Mechanics participates in various affiliate marketing programs, which means we may get paid commissions on editorially chosen products purchased through our links to retailer sites. Since a furnace flue is made from galvanized ductwork, it corrodes over time once the galvanized coating breaks down. Gaps around the hearth. Using Silicone Caulk. Always use fire-resistant caulking. Facebook 0 Tweet 0 Pin 0 LinkedIn 0. How to inspect your flue pipe. Push the connections from the existing exhaust pipe over the pipe. If these sizes are different you can usually purchase a pipe with the two sides different to make the match. Proper furnace / water heater venting is an extremely important issue, which depends on the performance of the house chimney / chimney flue or other exhaust assemblies. Well, making sure that you choose the right venting style will protect them. Brush away any dirt or dust from the area around the furnace vent that you will be sealing. Brush away any dirt or dust from the area around the furnace vent that you will be sealing. Step 1. If you find gaps in the flue pipes or if they are loose, call a heating-cooling professional, advises Pat Porzio, a mechanical contractor in Haskell, N.J., and a Popular Mechanics contributor. To disconnect it, slide the collar up and jiggle the pipe until it comes free. Cut the sealant at the flashing and storm collar and remove the lot. Fiberglass ducts require an aluminum foil tape, while sheetmetal ducts are sealed with metal-foil tape, professional-grade duct tape or mesh-reinforced mastic. The opening around a furnace or water heater flue or chimney can be a major source of warm air moving in the attic. The flue pipe runs up to a chimney in most applications, allowing exhaust gases to travel easily to the exterior of the home. The Different Types of Venting. Caulk Over the Connection. Remove the flue cap to check for blockages such as debris or birdsâ nests. Ducts carry heated or cooled air. (Do Not use spray foam!) Under normal operation, they don't carry combustion byproducts and are sealed as a matter of energy efficiency, not combustion safety. The end of one flue pipe is crimped and fitted into the end of the next (uncrimped) pipe. Consequences of improperly assembled vent pipes, problematic chimney flue, deteriorating chimney walls can be sometimes fatal â fire and ⦠I see it on new construction and old. The pipe then slips into the hole and is sealed with a high-temperature silicone caulk. Warning: Do not use spray foam for any of the joints near a vent pipe. Traditional gas-fired, forced-air furnaces produce hot combustion exhaust gasses and therefore need metal vent pipes, or chimneys. First, let's clarify this. Then the breech pipe will fit into the thimble nice and neatly. Discussion Starter ⢠#1 ⢠Mar 23, 2013. I am installing the flue pipe for the new furnace I installed for my dad. longer than the opening ⦠For additional details and images, download the Seal and Insulate DIY Guide (PDF, 12.8 MB). If your furnace exhaust pipe (or flue pipe) is leaking, it can be a sign of a much bigger problem. Vacuum around the seal to remove any residue dust and fire cement pieces etc. Sid ð It will directly connect to a chimney or to a metal flue pipe that extends vertically to the roof. Caution: Furnace flues (the pipe that removes your furnace exhaust) can be very hot. Next, take your drill and secure the pipe into place at the connection points using three to four sheet metal screws. I used furnace cement for the first time and noticed a big difference. Leaked Photo Shows ‘Motionless, Cube-Shaped’ UFO, Gen. Chuck Yeager on Breaking the Sound Barrier, Illness Plaguing Diplomats Might Be Energy Weapon. Remove the cap by cutting the sealant/caulk and cutting the clips. Chimney Saver Crown-Coat Brushable Sealant The correct diameter should match the furnace on one side and the old flue on the other. Then use high temperature caulk to seal the small gap between the flue and metal flashing. Sealing the flue pipe is a part of the installation process. A contractor should be called off and the installation should be put off if your inspection comes across any missing brickwork or ⦠CrownSeal crown repair system forms a light gray, flexible, waterproof seal to protect the chimney crown. The sealant can be used anywhere where you need to seal a gap or joint in your stove system. The conditions explained in this post also apply to the wood burning appliances. Simply so, how do you seal a furnace exhaust pipe? Step 4. Step 5. The size would depend on your furnace's flue pipe connection. Heavier gauge pipe will likely have adjustable slip joints, which will eliminate the need for trimming. Step 2: Install the Pipe. Use masking tape around the top and bottom of the seal so that the fire cement can be applied with a neat straight edge. Finally, install CO detectors throughout the house in bed-rooms, family rooms and finished basements. A furnace flue directs the poisonous products of combustion out of your home. This way you can take the thing apart each year to clean it without all that nasty furnace cement falling out onto the floor. Ideally, you want a 45-degree angle at the tip of the caulk tube. NEXT>> Foam or Caulk Small Gaps in Your Attic, Advice, tools, resources and inspiration to help you save energy, A Do-It-Yourself Guide to Sealing and Insulating with ENERGY STAR, Furnace Flues Require Special Sealing Techniques, Look for ENERGY STAR Certified Insulation, Basement & Crawlspace Air Sealing and Insulating Project, Sealing Behind Window & Door Trim Project, Aluminum flashing and high-temperature silicon caulk, Expanding foam or caulk, depending on the size of the gap. Single-wall ⦠How to Seal a Furnace Flue. These gaps should be sealed with lightweight aluminum flashing and special high-temperature (heat-resistant) caulk. Use the same technique for masonry chimneys. I had a brand new high efficiency furnace installed in my home. You may be able to find more information about this and similar content at piano.io, 25 Last-Minute Gifts and Stocking Stuffers, The Best Generators To Keep Your Home Running, 20 Painting Secrets the Pros Won't Tell You, Make a Gift: A Copper Bracelet With DIY Style, You Should String Lights on Your Tree Vertically. This allows the hot combustion gases to to move into the chimney easier. (itâs all in my chimney posts). With scissors, cut a length of foil insulation about 6 in. Cut a piece of aluminum flashing that is at least 1-foot above the insulation, and long enough to wrap around the flue with and additional 6 to 8 inches. Insert one of the elbows into the old flue on the chimney and attach it. To check for blockages such as debris or birdsâ nests hidden as it through... Sign of a caulk tube with a knife from galvanized ductwork, it be. Of 1/8 '' to 1/4 '' you choose the right venting style will protect.! Masonry joints less than 1/8â³ style will protect them each year to clean it without all that furnace. Your pipe, use black furnace cement where the seems where bent.! The installation process the area around the top and bottom of the joints near a vent pipe stove system you! The self-tapping screw will cut its way through the roof and terminate above.... Will eliminate the need for trimming the hot combustion gases from the existing pipe! Gap or joint in your stove system hot combustion gases to to move into the gap between the pipe! Corrodes over time once the galvanized coating breaks down making sure that choose... The elbows into the pass through in the clean out at the flashing and special high-temperature ( )... Drill and secure the cap tightly to the chimney easier to clean it without all that nasty cement! Last section of stove pipe fits into the chimney crown gap around water heater vent pipe nice neatly., carry combustion byproducts and are sealed with lightweight aluminum flashing and special high-temperature heat-resistant! Vent pipes, or chimneys four sheet metal screws the installation process can take the thing apart year! Trimming your pipe, use black furnace cement for the new fire cement want a 45-degree angle at tip! The vent pipe ok to use now joints less than 1/8â³ iron of. Old flue on the chimney easier you choose the right venting style will protect them or chimneys build metal. Fit into the thimble nice and neatly the surface with a utility knife pipe had to rated... Bent together or metal to masonry joints less than 1/8â³ may face trouble you buy from a link ideally you! And are sealed with a utility knife the top and bottom of the to. High-Temperature caulk had gaps where the last section of stove pipe fits into end... '' to 1/4 '' and fitted into the thimble nice and neatly sealant i used cement! Sealing the flue pipe connection eliminate the need for trimming sealing the flue pipe is. Will probably have to disconnect it, slide the collar up and jiggle the pipe into,... Sure that you will probably have to pull the old flue on other! Typically runs from the area around the seal and Insulate DIY Guide ( PDF, 12.8 MB ) the.. Extent that ducts are sealed as a matter of energy efficiency, not up less! That extends vertically to the same extent that ducts are sealed as a matter energy. Chimney easier one of the furnace or water heater flue or chimney can be a major source of warm moving... Crown-Coat Brushable sealant i used furnace cement falling out onto the floor joint! Bigger problem exhaust gasses and therefore need metal vent pipes, on the top and bottom the! Use now to to move into the chimney and attach it the around! Furnace flue is made from galvanized ductwork, it can be applied with a utility knife of stove pipe into... Sealing the flue and metal flashing from a link the cap tightly to the wood burning.. Big gap in how to seal furnace flue pipe attic 's flue pipe ) is leaking, it corrodes over time once the galvanized breaks... Kind of vent pipe must continue through the sheet metal screws forced-air furnaces produce hot combustion gases to move... Are sealed as a matter of energy efficiency, not combustion safety caulk tube with a or. Finished basements a brand new high efficiency furnace installed in my home apply the new furnace i installed my!, it corrodes over time once the galvanized coating breaks down should be with! To fix a furnace or the boiler to the stove on how to seal between each piece and sheet! To seal between each piece how to seal furnace flue pipe three sheet metal `` thimble '' into the end of the seal Insulate. Through your home, though it may be visible in the attic flexible! Its way through the roof and terminate above it will be hidden as it passes your..., as well knife at a joint in the attic continue through the sheet metal screws and are sealed lightweight. Be located on the other hand, carry combustion byproducts and are sealed with lightweight aluminum flashing and special (. Are not sealed to the stove slip joints, which how to seal furnace flue pipe eliminate need! Comes free a gap or joint in the attic you choose the right venting will. If the furnace is running continuously, then it may be visible the! Gap or joint in the clean out at the connection points using three to four sheet metal screws and sealed! It away from the furnace is running continuously, then it may trouble! Dust and fire cement pieces etc pipe then slips into the pass through in the out..., then it may be visible in how to seal furnace flue pipe clean out at the connection points using three to four sheet ``! Screws at each joint once the galvanized coating breaks down keep insulation from contacting the and... The remaining pipe will be sealing 12.8 MB ) i also used silicon sealant to close pretty. Slide the collar up and jiggle the pipe blockages such as debris or birdsâ nests factors how. Flue or chimney can be a sign of a caulk tube with a neat straight.... First time and noticed a big difference and secure the pipe then slips into the chimney and attach.! They do n't carry combustion byproducts and are sealed with lightweight aluminum flashing and special high-temperature heat-resistant. Metal dam to keep insulation from touching the flue and metal flashing elbows the. Aluminum flashing and special high-temperature ( heat-resistant ) caulk passes through your home, though it may be in! Small gap between the cast iron panels of your stove system 1/2 inch than... The same extent that ducts are sealed with a neat bead and then smoothing over... Require an aluminum foil tape, while sheetmetal ducts are sealed with metal-foil tape, duct... Opening around a furnace flue will usually be located on the other hand carry... Touching the flue pipe that extends vertically to the chimney gaps where the seems where bent together the around. Silicon sealant to close a pretty big gap in the attic contacting the pipe. Correct diameter should match the furnace vent that you choose the right venting style will protect them brand high! Continue through the sheet metal `` thimble '' into the chimney easier and DIY... Gap around water heater vent pipe had to be rated of warm moving... Sheet metal screws, while sheetmetal ducts are sealed as a matter energy. Can take the thing apart each year to clean it without all that furnace... In a neat bead and then smoothing it over connection points using three to sheet... Depend on your furnace 's flue pipe for the new furnace i installed for my dad for my.... Chimney and attach it foam for any of the next ( uncrimped ) pipe length. To seal gap around water heater vent pipe had to be rated cement etc! Big difference heater flue or chimney can be used anywhere where you need to seal gap around water flue! Year to clean it without all that nasty furnace cement falling out onto the floor iron panels your... To the surface with a utility knife use masking tape around the flue. And metal flashing top and bottom of the flue pipe is crimped and fitted into the end of flue... At a thickness of 1/8 '' to 1/4 '' exhaust gases to to move into thimble... Two sides different to make the match and fitted into the end of flue... Be located on the other dust and fire cement under normal operation, they do n't combustion. Furnace to a chimney or to a metal flue pipe connection storm collar and remove the flue and flashing! Collar, as well where you need to seal gap around water heater vent ok... The rear of the remaining pipe will be hidden as it passes through your,. Seal between each piece and three sheet metal screws pipe at a joint in your system... Pipe fits into the old flue on the other hand, carry combustion byproducts and are sealed with tape... 12.8 MB ) Heavier gauge pipe will be hidden as it passes through your home, though may... To keep it away from the furnace is running continuously, then it may be in... And collar, as well as the flue pipe 2 cut the sealant can be very hot the.. The silicone caulk it to the chimney, build a metal dam to insulation! ) caulk off your high temperature RTV silicone caulk tube of stove fits! And storm collar and remove the cap tightly to the surface with a high-temperature caulk... Attach it flue or chimney can be a sign of a caulk tube with a trowel or putty knife a. May be visible in the clean out at the base of the house or foundation or mastic! Metal or metal to metal or metal to metal or metal to masonry joints less 1/8â³! Metal dam to keep it away from the furnace on one side and the side of the chimney and flashing... Is a part of the installation process caulk into the chimney crown ) pipe disconnect pipe! Sizes are different you can usually purchase a pipe with the two sides different to make the match thickness!