PEX or Copper? Choosing Material for a Repipe Here

This article assumes the decision is made

Whether to repipe at all is its own question, and it turns on how many failures you have had, where they were, and how long you plan to stay. If you are still weighing that, the piece on repairing versus repiping an eighties house covers it properly.

What follows assumes you have decided. At that point the questions change entirely, and they are mostly questions people do not know to ask until the work is already underway and the answers have been decided for them.

There are four: what material, how much stays under the floor, what happens to the openings, and what else should be dealt with while access exists.

PEX and copper, without the ideology

Both are legitimate. Both are used constantly in this region. Anybody presenting one as obviously correct and the other as obviously wrong is telling you about their own habits rather than about your house.

PEX is flexible tubing. Its practical advantage in a house like this is that long runs can be pulled through a crawl space with very few joints, and a joint is where a supply system is most likely to fail. It tolerates movement, it is quick to install which affects labour cost, and it handles freezing better than rigid pipe because it can expand somewhat before splitting. That last point matters less here than it would east of the mountains, but it is not nothing during the occasional hard snap.

Copper is rigid, extremely well established, and preferred by many for exposed runs where appearance matters or where the pipe might be knocked. It is not affected by ultraviolet light, which matters for any short exterior section. It is generally more expensive to buy and slower to install.

The honest summary is that for a full house repipe run largely from a crawl space, PEX is the more common choice in this region for sound practical reasons, and copper remains a perfectly good answer where somebody has a specific reason to want it. What matters more than either is the quality of the installation and the fittings used.

The fittings question, which matters more than the pipe

If you take one thing from this article, take this. The tubing is rarely what fails. The connections are.

With PEX there are several fitting systems in common use, and they are not equivalent. Ask which system the contractor uses, whether it requires a specific tool they actually own, and how they handle the transitions where PEX meets existing copper or meets a fixture connection. Those transition points are where an otherwise good installation goes wrong.

With copper, ask about the joining method and about dielectric separation wherever copper meets a dissimilar metal. Joining copper directly to galvanized without proper separation sets up galvanic corrosion at the junction, and in a house where an older section is being retained that junction is exactly where a new leak will appear in a few years.

That second point is worth pressing on if only part of the house is being repiped. Repiping only a portion makes sense often enough, especially where an original wing and a later extension have had entirely separate histories. What it demands is that somebody thinks properly about the seam where the two meet, rather than dealing with it as the last job on the last afternoon.

The number that predicts your experience

Put the same question to everyone who quotes: how much of this work can you do from underneath, without cutting into any wall?

That single figure tells you more about how the job will feel than the price does.

A high figure means the only holes cut are where pipes come up at fixtures, with the bulk of the disruption confined to a space you never occupy, and the household staying put throughout with water off for planned windows rather than continuously.

Low means ceilings and walls, dust in living space, and a redecoration bill that can rival the plumbing. That is the version of this job most online advice is written about, and it is why the numbers people arrive with are often frightening.

The reason this question is worth asking here specifically is that the answer in this city is usually favourable. The standard build is a single storey or split level over a vented crawl space, which is a comparatively friendly place to run new pipe. A contractor who has not looked underneath before quoting has not established the number that matters most.

What happens to the openings

Get this in writing before work starts, because it is the most common source of a disappointing final invoice.

A plumbing quote that covers the pipework and stops at bare drywall is not a price for the job you want. Somebody has to patch, tape, texture and paint, and if that somebody is not in the quote then it is you, either with your own weekend or with a second trade at a second price.

Ask specifically: are openings closed and finished, to what standard, and is paint included. There are legitimate answers where the homeowner prefers to handle finishing themselves, particularly if redecoration was planned anyway. What is not acceptable is discovering the boundary after the plumber has left.

Ask about pressure testing too. A new system should be tested and held before it is signed off, and asking to see that happen is entirely reasonable.

Two smaller specification points are worth raising while you are asking. Where are the isolation valves going, because a repipe is the one opportunity you will ever get to put shutoffs somewhere sensible, and being able to isolate a bathroom without shutting the house down is worth a great deal over thirty years. And how is the pipe being supported and protected where it passes through framing, since unsupported runs move, and movement is what wears joints.

What else to do while the crawl space is open

This is the part people wish they had thought about, because access is the expensive ingredient in almost everything that happens under a floor.

If insulation is wet from whichever leak started this conversation, it needs removing and the space needs drying rather than being closed back up around damp material. In this climate that will not resolve itself, and proper drying is a different job from the pipe work rather than a consequence of it.

A camera down the side sewer costs very little on top of a visit that is already happening, and in a house of the age that needs repiping the lateral is usually of similar vintage. Knowing its condition while you have trades on site beats finding out separately later, and that is what a camera inspection settles in about an hour.

And if the vapour barrier is torn, displaced or absent, that is the moment to sort it. Nobody enjoys paying for a crawl space visit twice.