Pipes in the Cold Wall
This is the least glamorous page on this site and probably the most useful one. It costs a little now and saves a lot later.
How to tell
Relocating supply lines out of an exterior wall during a Lansing remodel adds $900-2,600; the same work after the tile is back on typically costs three to four times that.
- Work out which walls of your bathroom face outside. Stand outside the house and line up the window.
- Look at where the taps and the shower valve are. If they are on a wall that faces outdoors, the supply lines are almost certainly running inside it.
- Think back to cold snaps. Has water pressure ever dropped on a very cold morning, or has a tap ever run slow then come back once it warmed up? That is a partial freeze and it is a warning.
- Check whether anyone has told you to leave a tap dripping in winter. That habit is usually a response to exactly this situation.
A pipe does not have to burst to cause damage. Repeated partial freezing stresses joints and fittings, and the failure often happens months later on a mild day when nobody is thinking about it.
The single most common repair we hear about locally is not a burst main - it is a supply line in a bathroom wall that split at the fitting.
The three options, in order of preference
| Option | Typical cost during a remodel | Notes |
|---|---|---|
| Move the lines to an interior wall | $900-2,600 | Best. Removes the problem permanently |
| Keep them, insulate on the cold side | $250-700 | Acceptable when moving is impractical |
| Keep them, add heat trace cable | $300-800 | Works but relies on power and eventually fails |
The second option is the one to insist on if the first is impossible. The insulation must go between the pipe and the outside - not stuffed behind the pipe on the room side, which is the intuitive way to do it and the wrong way. Behind the pipe, the insulation cuts the pipe off from the heated room and makes freezing more likely, not less.
Common questions
Can I just leave the tap dripping?
It works, in the sense that moving water freezes at a lower temperature and a drip relieves pressure if ice does form. It is a mitigation, not a fix, and it depends on somebody remembering every cold night for the rest of the time you own the house.
Does this affect the drain too?
Drains are less vulnerable because they are not full of standing water and they are usually larger. A trap can freeze in a rarely used bathroom on an exterior wall, but supply lines are the real risk.
Will my insurer care?
They care after the event. A frozen pipe claim can be denied if the property was left unheated, and repeat claims affect renewal. Fixing it during a remodel is the cheapest insurance available.
Get it checked during your quote
Mention it when you enquire and a local contractor will look while they are measuring. Costs nothing to ask. No obligation.
Or call (877) 701-2518