Heat-trace or insulation for a drainpipe?
QUESTION: Can you please advise if my washing machine plastic drainpipe needs to be heat-traced or insulated in my cold crawl space? Some say yes, insulate. Others say no, heat-trace. Still others say as it doesn’t contain water, do nothing. Finally, a friend said, yes, insulate as there will be some condensation forming when the warmer basement air migrates up the open end and encounters the pipe in the crawl space area.
It has a good fall and a run of about 10 feet to where it penetrates the basement wall to dump water, about a three-foot vertical drop, into the laundry tub. Thanks very much for any clarification. Dan Hall, Toronto
ANSWER: You have posed a question about an unusual situation for a normally simple issue. The answer may depend on the insulation and average winter temperature in your crawl space, but also raises some other possible issues. Before I directly address your question, I will discuss these issues.
The normal situation for a washing machine drain hose is to discharge directly into a dedicated drain standpipe with a trap to prevent sewer gas intrusion into the living space. Because the waste water from the washer is discharged by a pump, the drainpipe should be reasonably well-secured to the drain pipe to prevent leakage.
Most washer drain hoses have a semi-rigid loop on the end to ensure they don’t easily pull out of the drainpipe when discharging. This loop can also be hooked over the edge of a typical laundry tub, as is the case in your home, as long as it is properly secured and the tub drain is properly plumbed. It is not wise to extend this hose to extreme lengths, as you have done, which may cause several problems.
To extend a washer drain hose to the length you have described, it will require at least one and possibly more joints. If the flexible drain hose is connected to other flexible material, the joints will have to be properly connected with pipe clamps. If lower-quality joint connectors are used, the pressure in the drain hose can cause the connectors to come loose or break. Also, a flexible hose of that length would sag significantly and will require proper support at many areas.
To jump ahead to your question, sagging sections of flexible hose would be more subject to freezing due to standing water in the pipes. However, the real concern would be leakage at the joints in the pipe should the connectors come loose, which would be difficult to see in the crawl space before significant leakage could occur.
I’m assuming you have run the long washer drainpipe in the crawl space because there are no accessible drains in the area in or adjacent to the laundry room over the crawl space. If there are drains nearby, perhaps in the walls or under the counter in a nearby bathroom or kitchen, a better option would be to attach a laundry drainpipe and trap to this existing drain. This would be dependent on the distance between the washer and the vent for the existing drain, but would eliminate two of your main problems.
Because this new drain would be completely within the conditioned space of the home, there would be no problem with freezing. Also, this new drain could be constructed of proper ABS piping with glued joints, which would eliminate the possibility of leakage from poor fasteners.
If there are no plumbing drains close enough to the laundry area to allow easy access, you should ensure you still have proper drain piping in the crawl space. By that I mean to suggest you replace any flexible hose with properly supported and sloped ABS pipes. This will not only prevent the possibility of leakage from loose pipe clamps but will only require minimal numbers of joints or connectors.
To accomplish this, the drainpipe should be installed according to the washer manufacturer’s instructions with a full standpipe inside the laundry room. This will allow you to install the washer loop into the top of the standpipe inside the laundry room where it can be monitored for leakage.
If you install a proper drain assembly in the crawl space, with proper slopes and minimal joints, it should not require heating or insulating. Because the water from the washer is forced into the piping by a pump, it is less likely it will have slow enough movement to freeze. This will only be completely true if you also connect the bottom of the drain to the proper drain piping below the laundry tub in the basement. This will allow the system to be primarily closed and prevent the warm air intrusion from the basement, which was another concern of yours.
It appears that you have a drain for your clothes washer installed by an amateur or do-it-yourselfer. These installations are not usually a problem if the distance is short between the washer and laundry sink. In your home, it can be much more of a concern because the drain is excessive in length and travels through an unheated crawl space.
Installation of proper ABS drain piping, complete with traps and proper venting, will eliminate most of your concerns with freezing. If you do not feel that this job is within your capabilities, contact a licensed plumber who will be capable of doing the job properly and according to the applicable building codes.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the president of the Canadian Association of Home & Property Inspectors — Manitoba (www.cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at (204) 2915358 or check out his website at www. trainedeye.ca