Replacing Poly with PEX without opening walls

[DavidBr]

I would like to replace my failing POLY with PEX all the way to the angle stop without opening walls. I have watched videos and googled it but I figure I would ask everyone to see what really works.

1/2 Poly
Interior Drywall
Most have 90 degree elbows in the wall

I have free access under the house so I can widen a whole to pull a 90 degree out.

Again, I would like to replace the poly inside my walls with PEX without opening the walls and I will not use 90's with the PEX, just a home run.

Ideas - what actually works?

Thank you.

 

[Reach4]

I would like to replace my failing POLY

I expect you mean polybutylene rather than polyethylene. Did you actually have a leak yourself?

You want to repipe your residence? I would think you would leave your old piping in the wall and run new around it.

With PEX, you are supposed to support it every 32 inches for horizontal. If you decided to ignore that, you might be able to fish the pipe in as you do when fishing wire thru finished walls. Perhaps it would be easier and better to just open the walls, install the new pipe, and get the walls re-drywalled. I am not a pro.

 

[Sponsor]

 

[DavidBr]

I expect you mean polybutylene rather than polyethylene. Did you actually have a leak yourself?

You want to repipe your residence? I would think you would leave your old piping in the wall and run new around it.

With PEX, you are supposed to support it every 32 inches for horizontal. If you decided to ignore that, you might be able to fish the pipe in as you do when fishing wire thru finished walls. Perhaps it would be easier and better to just open the walls, install the new pipe, and get the walls re-drywalled. I am not a pro.

Yes, I meant polybutylene - sorry about that.

We just remodeled the home and all the old poly crimps are starting to leak that was pre-existing. Rather not create new holes and new drywall work. What i have seen on youtube and google searches is to run a line in the pipe and then pull the old poly and the new pex should follow the line. They made it look easy in the video but I wanted to see if anyone actually tried anything.

 

[Gsmith22]

i would think how the existing pipe is attached to the framing will be your biggest obstacle in just being able to pull it out as you indicate. I doubt it is just floating in the wall. Then once out, how do you attach the new pex so it isn't banging around within the wall? Reach is correct about horizontal attachment at 32". Vertical attachment spacing is 5' (If I remember correctly). If you have access under the house (guessing crawl space) and it is a 1 story house with 8' ceilings and an attic, maybe its okay? But on its face, doesn't sound as simple as these videos you watched would indicate to remove or replace and attach properly.

 

[Reach4]

I wonder if your PB piping is clamped as pex usually is. That would keep you from being able to pull it out.

We just remodeled the home and all the old poly crimps are starting to leak that was pre-existing.

If it is just the fittings, there are transition fittings. https://www.lowes.com/pd/SharkBite-1-2-in-dia-Brass-PEX-Polybutylene-Adapter-Crimp-Fitting/1000182965

I read that the PB fittings with an aluminum ring had frequent problems.

 

[DavidBr]

i would think how the existing pipe is attached to the framing will be your biggest obstacle in just being able to pull it out as you indicate. I doubt it is just floating in the wall. Then once out, how do you attach the new pex so it isn't banging around within the wall? Reach is correct about horizontal attachment at 32". Vertical attachment spacing is 5' (If I remember correctly). If you have access under the house (guessing crawl space) and it is a 1 story house with 8' ceilings and an attic, maybe its okay? But on its face, doesn't sound as simple as these videos you watched would indicate to remove or replace and attach properly.

I would assume that it is fastened in the wall somehow and I thought about that. I have access under the house so the sticky part is mainly the toilets, showers and bathtubs. Under the sinks I can secure the PEX with a stub out or something because I don't have to open the wall and nobody will see it.

For the other areas - tubs and showers - i will have to connect under the house and hope that they don't fail in the wall.

For the exposed areas - the toilets - i want to use the same hole on the drywall side and hopefully the same hole in the sub floor - but I suspect I can open the sub floor hole a little if needed.

I suspect the longest length in the wall is less than 12-18 inches for the sinks and toilets, so the vertical should not be an issue - i assume??

I am trying to home run as much as possible, I am plagued by failing POLY and we want to rip it all out.

 

[Gsmith22]

is it the pipe that is failing, the fittings that are leaking, or both? reach has a good point about just dealing with the fittings if its only that

 

[DavidBr]

Its just the fittings but we are going to redo everything now so i dont have to crawl under the house when we are 80s. We are going to homerun with a manifold as much as possible.

 

[Plumber69]

I repiped a house like this, I managed to get all of it, But had to cut 4 holes in the drywall

 

[Reach4]

When I was fishing PEX, I had trouble locating my fish tool. What worked was shoving an LED light rope in from below. That lit up so I could see to snag that.

Under my enclosed lavatory, I was replacing drains too. So a bigger hole. I put thin interlocking flooring in the back of the cabinet I had cut through.

 

[DavidBr]

I repiped a house like this, I managed to get all of it, But had to cut 4 holes in the drywall

Were you able to resuse some holes and if so, how so?

 

[Plumber69]

Were you able to resuse some holes and if so, how so?

I drill new holes down thru the cabinets for bathroom and kitchen supplys, thru the floor for toilet

 

[WorthFlorida]

Just note that it will take forever with one person, about three times faster with a helper. As one is in the crawl space, the other is above.