Insulate to Prevent Frozen Pipes
+ Identify Types of Pipe Insulation

Add Water Pipe insulation to prevent freezing:

Insulation can be added to protect pipes routed through unheated 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 uninsulated, 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 uninsulated.

Does Insulation Prevent Pipe Freezing in Prolonged 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, unused heating pipes & heating oil lines 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.

Identify Common Pipe Insulating Materials

Below we provide a complete guide to different kinds of pipe insulating materials including common and modern products as well as photographs and properties of older pipe insulating products that are not found in newer buildings.

Photo: felted pipe lagging wrap material discussed in more detail below.

[Click to enlarge any image]

Pipe insulating products are sold in a variety of forms including foil faced, plastic faced, wrap-on strips, usually self-adhesive, and pre-formed foam or fiberglass insulating sections that are usually snapped over existing pipes or slipped over pipes during initial assembly.

• CREPE / KRAFT PAPER INSULATING PIPE WRAP
• FELT PIPE INSULATION, WOOL & OTHER
• FIBERGLASS, FOIL-FACED PIPE INSULATION
• FIBERGLASS PIPE INSULATION (PLAIN)
• FIBERGLASS PIPE INSULATION (FORMED, SPLIT TUBULAR)
• FOAM PIPE INSULATION (SPLIT TUBULAR)
• FOAM PIPE WRAP, ADHESIVE, FOIL FACED
• FOAM PIPE WRAP, ADHESIVE, PLAIN
• HESSIAN or JUTE PIPE INSULATION
• MINERAL WOOL PIPE INSULATION
• OLDER PIPE INSULATION PRODUCTS - including asbestos, sticky putty wrap, and magnesium carbonate insulation
• UNIDENTIFIED PIPE INSULATION - photos

Depending on where you live, pipe insulation may be referred to as pipe lagging or pipe felting or pipe sleeving.

Pipe insulating lagging may be sold as a tube or sleeve slipped over or onto piping or as a wrap-around product.

Identify Crepe / Kraft Paper Pipe Wrap

Shown above, Crepe or Kraft paper insulating batts, sometimes sold in narrow strips used as pipe wrap.

See details at KRAFT PAPER INSULATION CREPE KIMSUL

Identify Wool & Other Types of Felt Pipe Insulating Wrap

Felt pipe insulation or lagging may be stitched or plain, and are often a combination of animal, vegetable and man-made fibres needled or "felted" to adhere to form the insulating wrap shown above, sometimes sold with a polythene backing material.

Many felt pipe lagging products are made of natural sheep wool and by some vendors are referred to as "hair felt" pipe lagging or sleeving.

Below: this wool felt pipe wrap was found in a 1950s London home. Photo courtesy of an InspectApedia reader Daniel H.

Below: typical wool felt pipe wrap or lagging.

Also see

• SHEEPS WOOL INSULATION

Identify Hessian or Jute Pipe Sleeving, Insulation, Lagging

Felt sleeving products are a tubular insulation material intended to be slipped over new piping during initial assembly. Thinner felt sleeving is more useful (in our OPINION) as sound proofing or in moderate climates while in colder climates a thicker jute wrap like that shown below may be more appropriate.

Jute or other felted insulating product are produced by various methods to join fibers together to form a thick, cohesive mat by some means other than weaving (as in cloth), often by a combination rolling, pressing, wetting fibers with hot water, possibly using special needles.

Felting is one of the oldest methods for making fabrics, probably originating in the production of wool felts made by rolling up wool into a cylinder or ball and then stabbing it with a needle to cause the fibers to bind together.

Below: based on color and texture, this is probably jute pipe insulation wrap, courtesy of an InspectApedia reader, Jay.

Wrap-around insulation products like that shown below are intended to be added to existing piping installations by wrapping the material in a spiral around the pipe.

See details about Jute insulation at

• HEMP / JUTE INSULATION
• Samanta, Kartick K., Izhar Mustafa, Sayandeep Debnath, Esha Das, G. Basu, and S. K. Ghosh. "Study of thermal insulation performance of layered jute nonwoven: A sustainable material." Journal of Natural Fibers 19, no. 11 (2022): 4249-4262.
  Abstract: excerpt
  
  An eco-friendly sustainable thermal insulator has been developed as a replacement of some commercially available manmade materials to control heat transfer in case of buildings, and semi-permanent/temporary structures. Jute felts were prepared by needle pinching of fiber fleece.
  
  It is a self-sustained semi-rigid structure and could be placed on various surface profiles of the building/structure due to its balanced flexural rigidity and surface property of fiber. ...

On 2023-07-26 by Conor - what is this lagging on copper radiator pipes: Asbestos or something else?

Lagging on copper pipe for radiator, what's the thoughts, asbestos or something else?

This Q&A were posted originally at ASBESTOS PIPE INSULATION

On 2023-07-26 by InspectApedia Publisher (mod) - Jute-like pipe lagging insulation

@Conor,

That is "something else," other than an asbestos pipe insulation product, probably jute, hessian, or a similar plant fiber pipe wrap.

Notice its brown color and the coarse tan woody fibres.

On 2023-07-26 y CONOR

@InspectApedia Publisher, thank you!!

Identify Foil faced Fiberglass Pipe Insulation

Illustrated above.

Identify Plain Fiberglass Wrap Pipe Insulation

Illustrated above and shown below, plain fiberglass insulation is shown wrapped on a pipe, courtesy of an InspectApedia reader.

Identify Split Tubular Foam Pipe Insulation

As you can see from this example photo, foam pipe lagging or insulation is usually sold as a foam tube that is split lengthwise so that it can be opened and fit around existing piping. Typically this is a polyethylene foam productor "PE" in the product literature.

Some foam pipe insulation / lagging is sold unsplit and can be simply slipped over pipe during the pipe's initial installation. But if you find you've bought unsplit foam pipe insulating tubing that you need to install onto existing piping, simply slit the tubing lengthwise with a sharp knife. We sometimes use an old sharp bread knife.

Foam tubing pipe insulation is sold in various diameters whose internal opening diameter is sized to fit pipes of that outer diameter measure.

Identify Split Formed Fiberglass Pipe Insulation with a plastic or similar exterior barrier

Above: split fiberglass pipe covering.

Below: a larger diameter split fiberglass insulating product used on larger pipes or on HVAC air ducts.

Identify Foil faced Foam Wrap-around Pipe Insulation, self-adhesive

Illustrated above, this pipe wrap is self-adhesive.

Below: plain foam tape self-adhesive wrap-around pipe insulation.

Illustrated above.

Identify Mineral Wool Pipe Insulation

Illustrated above.

Excerpting from GLT Products' description given in detail below:

Mineral wool fabricated pipe and fittings insulation is made from felted mineral wool bonded with a high temperature binder.

The resulting product is precisely fabricated to fit NPS and tube sizes for both commercial and industrial applications. The temperature range is from -20ºF (-29ºC) to 1200ºF (649ºC).

See details at

• MINERAL WOOL - ROCK WOOL INSULATION
• MINERAL WOOL PIPE INSULATION PRODUCT DATA SHEET [PDF] GLT Products, SPI Corporate Headquarters 2101 Rexford Road, Ste 300E Charlotte, NC 28211 USA Tel: 704.336.9555 Tel: 1-800-874-1748. retrieved 2023/07/27, original source: gltproducts.com/user/general_pdfs/21091/pdfae48.pdf?t=1595346345
  Website excerpt:
  GLT Products is a ... manufacturer and producer of products that are used in both the industrial and commercial insulation markets.  Founded in 1956 under the originating title of Great Lakes Textiles, ... GLT was acquired by SPI in May 2021.

Identify Older Pipe Wraps & Insulating Materials (including Asbestos)

Watch out: Asbestos pipe insulation is not in contemporary use and may be hazardous if disturbed. See details

at ASBESTOS PIPE INSULATION

Putty type wrap-on stick-on pipe insulating products - below, courtesy of InspectApedia readers John & Lee.

...

This pipe wrap is a sticky, putty-like material that sticks to itself and to the pipe and may be black, gray, or white in colour.

Watch out: Some older versions of this pipe insulation might contain asbestos [not verified - Ed.]. Treat it as non-friable ACM or have a sample tested.

This insulation is discussed in detail at ASBESTOS PIPE INSULATION

Magnesia Carbonate Pipe Insulation - illustrated below.

Magnesia carbonate insulation as well as the uncertain pipe insulation shown just below are discussed in detail

at MAGNESIUM CARBONATE ASBESTOS PIPE INSULATION

Below: unidentified pipe insulation, appearing to include a combination of materials.

This product is discussed in detail at ASBESTOS PIPE INSULATION

Guesses at Unidentified Pipe Insulation Products

On 2023-07-26 by Craig - what is this unidentified pipe cloth lagging material?

I don't think it is asbestos, but would like another opinion.

The white cloth is soft to the touch where not covered with the yellow paint/sealer. I understand positive/negative confirmation is not possible based on image alone, your opinion on likelihood is appreciated. Thank you.

This Q&A were posted originally at ASBESTOS PIPE INSULATION

On 2023-07-27 by InspectApedia Publisher (mod) - white fabric, cotton or painted jute or something else?

@Craig, I agree that that pipe wrap looks like a painted cotton or maybe jute fabric but honestly I can't be certain from just the photo. Where is the building?

On 2023-07-27 by Craig

@InspectApedia Publisher, Thank you!

On 2023-07-25 by Jarvin - what is this wrapping material around a wooden strut - a bandage? Asbestos?

Hi, I know this isn't a pipe but I thought this was probably still the best place to ask!

I have this wrap around a single wooden roof strut in my attic space. I can't think why you would insulate a strut, but it struck me that it looked a little like it could be some sort of wrap insulation.

The property was renovated in the 1970s. It looks like a bandage to me, but I was concerned it could be some sort of ACM.

What do you think? Thanks in advance.

This Q&A were posted originally at ASBESTOS PIPE INSULATION

On 2023-07-25 by InspectApedia Publisher (mod) - elastic bandage wrapped around a trip hazard?

@Jarvin,

I agree that the material in your photo looks like an elastic bandage - not something that would be an asbestos insulation product.

I would unwrap it from the wooden member - post another photo of what you see.

Perhaps it was put there to buffer impact after someone bumped their shin, or perhaps simply wrapped by a child.

Let's see what you find.