How to freezeproof a building: where pipes freeze.

This article discusses the details of winterizing a building to prevent freezing pipes, focusing on how to find and fix cold spots that lead to frozen pipes in a building.

If your pipes are already frozen this article points to places to look for the most-likely places where freezing may have occurred in your water supply system.

Our page top photo illustrates a common point at which water supply piping is at extra risk of freezing - in a hard-to-access, poorly-insulated corner of a building.

The articles at this website 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 & dr ain piping, wells, & water tanks.

Guide to Finding & Correcting Freeze-Up Risk Points in buildings

You can do a lot to correct a freezing pipe problem in a building that is exposed to cold weather. Even in an occupied building pipes can freeze in some conditions. Here are some examples of places to look for freezing trouble and what to do about them:

What are the most common places where water pipes, drain pipes, or heating pipes freeze?

Our photo at left, a close-up of the page top photo, shows one way that pipes burst from freezing: ice forming at a specific location in the copper pipe expanded causing a round bulge that ultimately splits.

Common locations where heating tapes are used on plumbing to prevent freezing pipes include these high risk freeze spots for water supply piping, water drain piping, and in some circumstances even the hot water heating piping, baseboards, or radiators in a building:

• Water pipes run through attics
• Water pipes run through un-heated floors
• Water pipes run through un-heated crawl spaces
• Water pipes and equipment in un-heated garages
• Water equipment in well pits
• Water pipes running under porches
• Water pipes run along or near the building perimeter in a basement or crawl space, where lack of insulation or cold air drafts create pipe freeze risk points
• Hot water heating system pipes that run along the foundation wall top, at building outside corners, where there are outside cold-air drafts, and when heat is left off sufficiently long for the pipe to freeze. Rather than relying on heating tapes on heating pipes (which sounds ridiculous if not dangerous) you should be fixing drafts, re-routing piping if necessary, or for heating system piping, using an antifreeze mix.
  
  See ANTIFREEZE for BOILERS

Some older or less costly models of heating tapes present a fire risk, particularly if the heating tape is crossed over itself. Be sure to read the product specifications, safety warnings, and installation guide before installing a heating tape on building piping of any kind.

Check the routing of both hot and cold water supply pipes to identify spots where freezeproofing is needed

Water pipes 

(both supply & drain) & hot water heating pipes or steam heat condensate pipes or building drains routed through un-heated areas or passing by areas exposed to cold drafts.

Check piping that runs along or near the building sills or building perimeter in basements, crawl spaces, attics.

Check water supply piping and horizontal drain lines and fixture traps in cold areas where building heat does not easily enter, such as the pipe chase at left.

Often you can simply cut an opening to let warm air enter such spots - a technique that we illustrate later in this article.

Our photo (above left) provides a closeup showing one of several patterns in which a copper water pipe will swell and burst due to freezing. Details about the different patterns in which pipes freeze and burst are

at PIPE FREEZE-BURST PATTERNS.

• Look for drafts: 
  
  On a cold, windy day, explore your home, especially the un-heated areas such as where pipes pass along or close to the building perimeter sills or foundation top in basements or crawl spaces.
  
  If the building has sections of floor that overhang lower parts of the building (such as a raised ranch) be sure the floor under-side is well-insulated and thoroughly sealed against drafts. When cold wind blows against a home which has an overhanging floor, wind against the building can force cold air into the wall cavity or even up into the building walls through a poorly-sealed under-side of the overhanging floor.
  
  Explore the building on a cold windy day, looking for drafts: feel for cold drafts that blow on water piping or heating piping. Fix those drafts and you'll significantly reduce the chances of a frozen pipe. Fixing a draft means adding caulking, a plastic air barrier, using foam insulation, or other means to block un-wanted air flow into a building.

• Look for places where pipes touch un-heated surfaces,
  
  such as foundation surfaces or framing. These may conduct heat away from the pipe and speed freezing at that point.
  
  Our photo (left) illustrates a solution to a problem with pipes that froze repeatedly where they ran along the floor touching baseboard trim that was against a cold wall of a 1920's home in New York.
  
  We moved the hot and cold water pipes to the room interior, used supports to hold the pipes 1/2-inch off of the trim board, then for better appearance we "boxed in" the hot and cold water pipes with a white-painted cover.
  
  The red and blue lines portray water pipes that are actually hidden by the cover. By leaving 1/2" of air space at the cover bottom and a still smaller gap between the L-shaped cover and its abutment to the house wall, warm air circulates by convection (orange arrow) keeping these pipes from freezing.
• Look for the coldest of the un-heated areas
  
   where pipes run, such as an un-insulated attic, a pipe chase in a building corner, a crawl space (especially near foundation vents or other drafty spots), or as we explained just above,
  
  in a raised-ranch type home, where pipes run in the section of an upper floor which overhangs the building foundation (and may be poorly insulated).

• Look for evidence that pipes have frozen before,
  
  and find out why the freeze occurred in that spot.
• You may see a bulged pipe that didn't burst
  
   (if it burst it would have leaked and been repaired),
  
  or you may see a section of piping with one or even several pipe couplings soldered in place, a likely indicator that that section of piping has frozen before.
  
  In our photo at left you can see that freezing has damaged the heating baseboard pipe and a copper pipe coupling has been used to make a repair by replacing a damaged section.

Plumbing fixtures in un-heated areas such as a bathroom or kitchen sink in a room that does not have its own heat source;

in kitchens and bathrooms we may leave open vanity cabinet doors to permit warmer building air to reach pipes in those areas.

Freeze-protect outdoor faucets to avoid a building flood

Plumbing faucets outdoors:

traditional simple hose bibs or outdoor faucets can easily freeze where they pass through the building wall if the faucet is not shut off and drained; longer-stem frost-proof outdoor faucets are available and are used in new construction in most jurisdictions.

These newer faucets make sure that the actual valve that turns off water flow is well inside the (supposedly heated) space.

Our photo (left) shows what we found on arriving at an unoccupied New York home shortly after freezing conditions had abated. Water was spewing out of the building wall just above the foundation.

The owner/occupant had forgotten to turn off water to the outside hose hook-up, leaving that line full of water. The water line just inside the foundation froze and burst.

If your outdoor faucet is the older type that is not frost-proof, you should be able to turn off water to that faucet and open a small screw fitting on the faucet body side to assist in draining that device when draining the building piping.

Even in a building where heat and water are being left on for the winter we make sure to find and use (or install if needed) the valve to turn off water to each outdoor faucet. Then we open the faucet to let it drain, leaving it open (and making sure it's not dripping from an indoor shutoff valve that is not working well).

Never leave a garden hose attached to your outdoor faucet in winter as water in the hose may add to the risk that the faucet will be freeze damaged.

See details about outdoor faucets, hose bibbs, sillcocks at FAUCETS, OUTDOOR HOSE BIBBS

and at FAUCET, SILLCOCK ANTI SIPHON / FROSTPROOF LEAK REPAIR.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: our space heaters still haven't thawed out our frozen water supply pipes

2018/02/03 Jeanette said:

Space heaters been on 13 hours and no water

This question and reply were posted originally at WELL PITS - designed to avoid frozen well heads for well casings that are not completely buried below the frost line.

Reply: where to look to find which pipes are frozen when you have no water

Jeanette

I am GUESSING that you are saying your pipes were frozen and you had no water and you're trying to thaw things out.

You need to trace the piping to find the most-likely frozen spots and add heat in those areas.

See details in the article above on this page where we mention where water supply pipes are most-likely to freeze

and HEAT SOURCES to AVOID FROZEN PIPES (live link is given in the article list below) where we suggest where to add heat.

If your drains are also found frozen, see DRAIN FREEZE PROTECTION (live link is given in the article list below) where we give examples of where pipes freeze on drains

On 2017-01-28 by Donna

we have a crawl space under our house. with a sump pump and it discharges outside this year we had very cold weather and our pipe froze. Should we try heat tapes?

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Continue reading  at PIPE FREEZE PROTECTION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Pipe Freeze Protection Articles

• ANTIFREEZE for BOILERS
• DRAIN a WATER HEATER TANK
• FAUCETS, OUTDOOR HOSE BIBBS
• FREEZING FORCE of ICE
• FROZEN PIPE THAW-OUT
• GREYWATER FREEZE PROTECTION
• PIPE FREEZE PROTECTION - home
  • DRAIN FREEZE PROTECTION
  • HEAT SOURCES to AVOID FROZEN PIPES
  • HEAT TAPES to AVOID FROZEN PIPES
  • HEAT TAPES on OIL TANK PIPING
  • HEAT TAPE HAZARD ON OIL TANK
  • INSULATION to AVOID FROZEN PIPES
  • PIPE FREEZE-BURST PATTERNS
  • PIPE FREEZE-UP POINTS
  • PIPE INSULATION CHOICES, MATERIALS, TYPES
  • WELL SNIFTER & DRAIN BACK VALVES
• WINTERIZE A BUILDING - home

Suggested citation for this web page

PIPE FREEZE-UP POINTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING FREEZE PROTECTION

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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