How to Insulate CPVC

Insulating your water pipes can shield them from freezing during winter weather. It can also reduce noise from water hammering and protect the pipes in the resulting vibration. Chlorinated polyvinyl chloride (CPVC) pipe is recommended over PVC for warm water plumbing because it has a greater temperature tolerance (180 degrees Fahrenheit compared to PVC’s 140-degree rating). CPVC can be securely insulated with the majority of the same techniques and materials as other pipes with a single exception.


Looking for pipes can be found at most home improvement stores. Split-foam sleeves offer you a secure and simple way to rapidly insulate long, straight pipe runs. Fiberglass batting strips with foil or paper backing can also be effective. These need a bit more effort to implement properly and require some security gear for good handling. The only insulation material that should specifically be prevented is spray-on insulation. This kind of insulation is applied in a spray-paint style can and, while convenient, contains chemicals that degrade CPVC pipe and also causes little cracks that may cause leaks or a complete pipe failure.


A sharp utility knife works well to trim and cut both the polyurethane glass and sleeve batting kinds of insulation. Always wear safety goggles, breathing protection and protective gloves when handling glass batting insulation. Immediate exposure to fiberglass can cause skin, eye and respiratory irritation.

Foam Sleeve Application

Foam heels come in the factory split along their length. This split makes use as simple as cutting the sleeve into the appropriate length with a utility knife and also spreading the split borders to fit them over the pipe. Once set up, the sleeves should be secured with tape or plastic cable ties. The tape or ties should be tightened just enough to hold the sleeve in place. Overtightening compresses the foam tube, causing it to eliminate some of its insulation value.

Fiberglass Application

Fiberglass pipes insulation is supplied in narrow rolls. The roster is wrapped in a spiral around the pipe and secured with tape or cable ties. One benefit of utilizing fiberglass batting over foam sleeves is the fact that it’s simpler to install over elbows and other fittings. While these can be problematic with preformed sleeves, simply changing the angle or direction of the wrap enables you to cover the combined or matching without leaving a gap. Much like foam sleeves, you want to apply the tape or tie just tight enough to hold the insulation in place.

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