Restoring a 1915 Colonial Revival house
Heat Pipe Insulation


The first winter we spent  in the house was one of the worst winters on record for the state of Maryland. We had three blizzards in the same winter and a total snowfall of over 80 inches. Needless to say, the heat ran a lot that winter. One thing we noticed when the heat was running was how warm the basement was compared to the rest of the house, which made sense. There was over 200 linear feet of cast iron pipe in our basement circulating 140 degree water that was not insulated. The uninsulated cast iron pipe was acting like a large radiator and made the basement about 80 degrees while the rest of the house was freezing.

Before I go on, I think everyone should know why these pipes were not insulated. When we first looked at the house, the heating pipes were insulated with asbestos wrap that was encapsulated in a layer of plaster. We didn't have a problem with that, but our lender was nice enough to bring our loan application to a screeching halt over it and almost caused the deal on the house to fall through. Their excuse was they didn't want to finance a house that was a "health hazard". Needless to say they were overreacting a bit, as the asbestos was encapsulated. They required an asbestos contractor to come in and remove the insulation and charge the seller of the house several thousand dollars.

This would be a good time to talk about asbestos and safety precautions that should be observed around it. Asbestos was used in thousands of everyday products manufactured in the US and around the world from around 1910 through the mid 1980s. Virtually every house built before about 1985 has asbestos in it somewhere, whether it be pipe insulation, tile, roofing material, etc. Ever since about 1990, it seems that there has been a witch hunt mentality about asbestos and it's many supposed evils. Yes, asbestos is a hazardous material and should be treated with respect. HOWEVER, asbestos, especially if it is encapsulated like it was in the case of our heating pipes should be LEFT ALONE. When the insulation is removed, it allows the asbestos fibers that separate as the insulation breaks off to become airborne. Airborne asbestos fibers become an inhalation hazard, a condition they would not be in if the asbestos material had been left alone in the first place.

Bottom line was, our insulation was gone. And it was now winter and the basement was about the only comfortable area of the house. We needed to quit wasting heat down there and push more of it upstairs. We looked around locally for heat pipe insulation, but were unable to find anything in the area. Either no one had it or they didn't have enough to do a job the size of ours. And, to complicate matters even more, our heat pipes consist of several different diameters of pipe.

We ended up ordering the pipe insulation we needed from Express Insulation. Total cost was about $450. The insulation is manufactured by Knauf and comes in three foot lengths. The inner tube is made of fiberglass and there is a heavy paper backing on the outside.




To give a little extra insulation, we started out by wrapping the heat supply pipe going through the basement ceiling to the radiators in narrow strips of fiberglass. This will make the tubes of pipe insulation a little more secure and add extra insulating capability. The way the pipes are arranged in the basement, it made the most sense to start working along the walls at the hardest to reach pipes and work our way outward.



After the fiberglass was wrapped around the pipes, it was time to put on the pipe insulation. The paper backing on the tubes on insulation have adhesive on the ends where it wraps around the opening in the tube as seen below:



When the tube is closed, the adhesive on the paper backing keeps it in place.



With the linear pieces of heat pipe insulated, we still had to address the joints. We did this by wrapping the joints and ells with the same fiberglass strips as we did on the pipes. Once they were wrapped to where the thickness matched the insulation tubes, they were covered in jacket tape. Below are the tape and fiberglass strips we used. They are available at most hardware stores.






With the pipes insulated, we could immediately tell the difference in the temperature of the house. The first and second floors were now warm, the heat wasn't escaping into the basement, and the boiler wasn't running as long or as often.

This was one of our first small victories with the house after we moved in.