Where & How to Add Insulation to Prevent Frozen Pipes
INSULATION to AVOID FROZEN PIPES - CONTENTS: how & where to add pipe insulation or other insulation for freeze protection of supply piping, drain piping, fuel piping, & heating system piping in buildings
POST a QUESTION or READ FAQs about how to protect buildings from freeze damage: prevent frozen pipes, frost heaves, cracking due to freezing, and prevent water and mold damage that follows frozen, burst pipes.
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Pipe freeze-protection for buildings:
This article explains where, why, and how to add pipe insulation or in some cases building insulation and draft-stopping materials at cold problem spots to avoid freezing pipes.
The articles in this series will answer most questions about freeze protection for piping and other building plumbing and heating system components: how to winterize a building to avoid frozen pipes, and how to thaw frozen water supply & drain piping, wells, & water tanks, heating system piping and heating oil piping.
Add Water Pipe insulation to prevent freezing: can be added to protect pipes routed through un-heated areas or near cold building corners. We particularly like to add slip-on foam pipe insulation where a plumbing line is run past a cold spot that is hard to warm up.
Some writers believe that if you insulate all of your water supply piping you won't have a frozen pipe problem. That may be a bit optimistic: we fear that a cold corner somewhere will be missed and left un insulated, or that a house left without heat for too long will get cold enough to freeze even an insulated pipe.
The advantage of insulating pipes is that it slows the rate at which a water pipe will freeze, possibly getting the pipe through the coldest part of the night and into a (hopefully) warmer daytime to warm-up again.
Remember, when insulating a water pipe, that you need to insulate all of it. Don't leave those awkward elbows or pipe tees un insulated.
Does Insulation Prevent Pipe Freezing in Prolong Cold Periods? Probably Not.
Watch out: Here is a speculative warning about relying on pipe insulation alone to avoid freezing, that is, we don't have hard science to back up this opinion:
Insulation on a water pipe will often protect building supply or drain pipes, un-used heating pipes & heating oillines from freezing during a brief spell of freezing temperatures.
But during a period of prolonged very cold nights and only moderately warmer days, we are not so sure that the insulation permits the pipes to accumulate "cold" rather than warmth. When this is the case, ultimately the pipes reach the freezing point.
Plastic piping to resist freezing: modern plastic piping is considerably more tolerant of freezing without bursting than copper or steel water pipes. In a home intended for regular winterization some builders use exclusively plastic pipes to resist freeze damage.
Watch out: even when freeze-tolerant piping is used, the piping connections, elbows, unions, couplings, and plumbing fixtures are still at risk of frost damage.
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what about using heat tape on sewer pipes - our mobile home sewer line keeps freezing
You don't say anything regarding using heat tape on sewer pipes. We have an annual problem with a mobile home sewer line freezing. The line connects a toilet, shower and tub so when it freezes it is a mess. - Anon. 9/19/11
Anon, you can add a heat tape on a sewer line provided the tape you choose is connected and secured to the sewer line the way the manufacturer instructs. Make sure that the bottom of the waste pipe is in contact with the heat tape, and provided the heat tape manufacturer permits, insulate the line as well. The combination of a proper heat tape and sewer line insulation is usually enough to stop freeze-up but here are some additional tips for mobile home waste line freeze problems:
Watch out: some heating tapes cannot safely be used on drain pipes, possibly because of a concern for heat damage to the piping. Details are in the article above at HEAT TAPES to AVOID FROZEN PIPES
Because the waste line typically has a vertical segment between the floor of the mobile home and the ground and because that segment is exposed to cold air in the crawl space beneath the home you will want to insulate it. But in termite prone areas the risk is that your insulation provides an insect path from the soil up into the floor of the home. Ask your local pest company for advice about protecting this area from insects or perhaps construct a surrounding (openable for inspection and repair) partition wall that uses termite shields.
Watch out for dripping faucets and running toilets. A drain line does not normally contain standing water but when routed through freezing spaces and when there is a small rivulet of water in the drain due to a slow leak indoors such as a drip or running toilet, that water can freeze and accumulate until the line becomes blocked, frozen solid, and burst.
Question: what kind of heating tapes can be used on PVC plumbing drains?
I have a PVC drain line for my water softener that goes outside. When it got very cold two winters ago, the drain line froze and it backed up into house. The drain line lays on the ground. I went to a local store to look for heat tape and they specifically stated not to use on drain lines. Is there some type of tape I could use that would be safe, and how should it be installed? - Don Corbett 9/30/11
A concern with heat tapes on plastic piping is that it may damage the pipes. And if your water softener drain is simply draining onto the ground surface, that is an improper and illegal disposition of wastewater in just about every jurisdiction. Unfortunately the proper fix is costly: reroute drainage to a drywell or other approved drainage destination.
If you use drain piping of sufficient diameter and proper slope, even exposed to cold temperatures the drainage will generally not freeze up in normal use. More help on avoiding freezing piping is at WINTERIZE A BUILDING.
Heating tapes and cables can be installed on PVC supply and drain piping provided you choose the right kind of heating tape or cable and that you follow the manufacturer's instructions. Details are in the article above at HEAT TAPES to AVOID FROZEN PIPES.
Question: is it OK for the water line to run atop a concrete slab or should it be under ground?
In a mobile home in N.E. should the water supply line be placed on top of the concrete slap for 30 feet or more. Would that be up to code?
Should the line from the street be 4 feet under ground to within 6 feet of the hot water heater? - Lee Broad 1/23/12
Lee, if you are describing a water line atop the rat slab beneath a mobile home, there are a couple of hazards including freezing and also movement-caused abrasion and leakage. If the line is supported off of the slab by blocks and insulated you may be OK, else you'll need to add frost protection as well. Heating cables (see advice above in this article) are readily available in lengths up to 60 ft. so you won't have trouble finding one long enough. Don't buy one longer than you need and be sure it is connected according to the manufacturer's instructions.
Question: what is the best way to heat a well pit?
what is the best way to heat a well pit - Jim, 10/18/2012
A well pit is intended to protect its contents, well head, piping, possibly even a water tank and pump from freezing by its depth below ground. If you have to add heat then the pit was perhaps not properly constructed, not deep enough, or left uncovered.
That griping done, you could consider adding a small electric heater; We have also used a simple light bulb in a small, closed well pit. The risk of course is that electricity fails or the bulb burns out. That's why I think a small oil-filled electric heater is probably more safe. Be sure that ALL electrical components in a well pit are protected from water, including the occasional well pit flood. - See more at: https://InspectAPedia.com/plumbing/Pipe_Heat_Add_Points.php#sthash.Nk3hbfK8.dpuf.
Question: tips on how to use a circulating pump to prevent water from freezing
Great suggestions - good article!
Beside insulating pipes from cold weather, or trying to use heat tape, a very effective way of protecting pipes from freezing is to introduce a circulating pump into the water system. By installing a circulation system, the water from the 'hot' side of the system gets sent to the 'cold' water line. This greatly reduces the possibility of water pipes freezing because the water temperature never reaches the critical freezing point.
The best circulation system on the market that I've seen is available at http://avoidfrozenpipes.com/ It is the only circulating pump I've seen that doesn't need electricity to run. It can be installed anywhere in the water system, and save hundreds if not thousands of dollars in home repairs if frozen pipes burst from water expansion.
That's my two cents; I hope it helps! - Vincent 1/21/2013
Thanks so much Vincent. We welcome content critique & suggestions for InspectApedia articles. Working together we are smarter than any individual. - Daniel
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Questions & answers or comments about how & where to add heat as a means to protect pipes from freezing. .
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 "New Electric Heat Tapes Help Prevent Fires," US Consumer Product Safety Commission (CPSC) #00936
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: email@example.com
 "Freezeproof Your House," Mike McClintock, Rodale's New Shelter, p. 30, October 1985 (approximate date)
 "How to Winterize Your Pipes," Mike McClintock, Homeowners How-To Magazine, p. 59-62, Nov-Dec 1979.
 "HUD Regulation for Manufactured Homes; Requirement that Heat-Tape not include a GFCI [ copy on file as /plumbing/GFCI_Heat_Tapes_HUD_CPSC_Letter1994.pdf ] - ", Meeting Log, US CPSC, HUD, Dennis McCoskrie, ESEE, 2/14/1994
 Thanks to reader Ryan T. Duffy for discussing the suggestion for GFCI's on heat tape circuits to reduce fire risk, October 2010.
 Easy Heat heating cables, "Easy Heat AHB-013 Cold Weather Valve and Pipe Heating Cable",
http://www.emersonindustrial.com/, retrieved 3/2/2013,
Product Description: Temperature-controlled cable runs straight along pipe and valves, held in place by application tape and plugs into grounded electrical outlet. Keeps water flowing down to -380. For odd lengths of pipe over 3/4 inches in diameter, we recommend two separate cables on opposite sides of the pipe with up to 3 feet of overrun at center of pipe run. Metal pipe requires 1/2-inch fiberglass insulation around cable. For plastic pipe, its recommended wrapping pipe with aluminum foil before cable installation. The traditional resistance cable produces a fixed amount of heat based on the electrical line feed. It comes with a built-in thermostat that switches the flow of electricity on and off based on temperature. Cable installs fast and easy. Each package contains grounded plug, built in thermostat and instructions. Cable has weather resistant PVC outer jacket and inner insulation. Keeps water flowing down to 40 F.
 Easy Heat, "Easy Heat® Freeze Free® Preset Thermostat (EH-38)" , EGS Electrical Group, 9377 W. Higgins Rd.
Rosemont, IL 60018, USA or EGS Electrical Group, 99 Union Street
Elmira, ON N3B 3L7, Canada. Tel: 800.621.1506,
Product specifications: 15 amps, 120 volts
Thermostat for use with Freeze Free Self-Regulating pipe heating cable,
For dry location only,
 RayChem "Self-Regulating Pipe Heating and Roof/Gutter De-Icing Cable", Rachem Corporation, 300 Constitution Drive, Menlo Park, California 94025-1164, U.S.A., Website: http://raychem.te.com/, retrieved 3/2/2013, Product Description:
Self Regulating Heating Cable, Mounting Location Dry, Cable Length 50 ft., Max. Circuit Length 200 ft., Voltage 120, 6 Watts per Foot @ 40F, 0.050 Amps per Foot @ 40FFeatures Self Regulating, Automatically Adjust Heat Output, For Use With Lighter Plastic or Metal Pipes Up to 8 In. Dia., Standards UL Listed and CSA Certified, Includes Cable Only;
Characteristics : Tough Metal Braided Self Regulating Heating Cables, Can be Overlapped and Insulated without Overheating or Burning Out, Automatically Adjust Heat Output at Each Point Along its Length without Using Thermostats, Standards : UL Listed and CSA Certified, Includes : Cable Only
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