Replacing section of lawn sprinkler pipe

[Rebel1]

I have to replace about 20 feet of 1-inch black poly pipe between the house and the five-zone manifold. About six feet of the pipe passes under a paver brick walkway, which I don't want to disturb. The pipe is about 6-8" below the soil, in Central New Jersey.

The first sprinkler company I called said the walkway must be disturbed, and it would be up to me to make arrangements to remove and restore the pavers. If I tackled that job myself, then I could easily replace the pipe as well.

The second company said he would simply pass a 3/4" section of pipe through the existing 1" pipe under the walkway, then use adapters to transition back to 1 inch. (I don't know if meant to make the entire run

3/4" or just the part passing under the walkway. He's looking over the job tomorrow.)

I asked about the reduced flow available through the 3/4" pipe. He said that as long as I don't have more than five sprinkler heads on a zone, I would be okay. My heads are by Hunter and there are only five per zone, so it sounds okay.

Any other suggestions for not disturbing the walkway, or comments on using 3/4" pipe?

Thanks,

Ray

[Rebel1]

I have to replace about 20 feet of 1-inch black poly pipe between the house and the five-zone manifold. About six feet of the pipe passes under a paver brick walkway, which I don't want to disturb. The pipe is about 6-8" below the soil, in Central New Jersey.

The first sprinkler company I called said the walkway must be disturbed, and it would be up to me to make arrangements to remove and restore the pavers. If I tackled that job myself, then I could easily replace the pipe as well.

The second company said he would simply pass a 3/4" section of pipe through the existing 1" pipe under the walkway, then use adapters to transition back to 1 inch. (I don't know if meant to make the entire run

3/4" or just the part passing under the walkway. He's looking over the job tomorrow.)

I asked about the reduced flow available through the 3/4" pipe. He said that as long as I don't have more than five sprinkler heads on a zone, I would be okay. My heads all popups, mostly rotaries by Hunter, but a few non-rotaries, and there are only five per zone, so it sounds okay.

Any comments on using 3/4" pipe, or other suggestions for not disturbing the walkway?

Thanks,

Ray

[jamesgangnc]

I think the 3/4" solution will be fine. A small section of 3/4 won't have that much impact on your flow.

[Rebel1]

I have to replace about 20 feet of 1-inch black poly pipe between the house and the five-zone manifold. About six feet of the pipe passes under a paver brick walkway, which I don't want to disturb. The pipe is about 6-8" below the soil, in Central New Jersey.

The first sprinkler company I called said the walkway must be disturbed, and it would be up to me to make arrangements to remove and restore the pavers. If I tackled that job myself, then I could easily replace the pipe as well.

The second company said he would simply pass a 3/4" section of pipe through the existing 1" pipe under the walkway, then use adapters to transition back to 1 inch. (I don't know if meant to make the entire run

3/4" or just the part passing under the walkway. He's looking over the job tomorrow.)

I asked about the reduced flow available through the 3/4" pipe. He said that as long as I don't have more than five sprinkler heads on a zone, I would be okay. My heads are all pop-ups, mostly rotaries by Hunter, but a few non-rotaries, and there are only five per zone, so it sounds okay. One site says that typical head delivers 1/2 gal/minute, so with five per zone, that's 2.5 gpm, well below what a 3/4" pipe can deliver (about

23 gpm).

Any comments on using 3/4" pipe, or other suggestions for not disturbing the walkway? One website suggested blasting a hole using full-force water through a garden hose. Other suggestions are here:

Thanks,

Ray

[trader4]

First question is, what's wrong with the 1" section that runs under the sidewalk now? Usually this pipe lasts virtually forever, unless it gets damaged. Unless there is evidence that it is all failing for some reason, then I'd just leave the section under the sidewalk and use it.

Second, any irrigation company that tells the homeowner they have to remove the paver sidewalk is being run by idiots. Any decent company has the eqpt to easily get a 1" pipe under a sidewalk. They use a driving tool that is powered off an air compressor and do it every day to cross 20ft driveways or more.

In your case, that span could also be crossed by hand, using a steel driving pipe and sledgehammer without very much difficulty.

The 3/4" pipe solution for the sidewalk could be OK. Besides the number of heads, it also depends on how many GPM the heads. But I have to wonder. Will 3/4" pipe fit thorugh 1" pipe? Would seem to me it could be a close fit.

[ransley]

When mine broke they just pulled a new section through, but I wasnt there to see how it was done. Call companies till you get a real pro that has equipment and knows how to do the job. Cutting the size of the pipe will probably cut flow in half, I would not remove the pavers since they will never be the same, the dirt will settle over time and you will have a depression in the pavers.

[Andy]

Andy comments:

The 3/4 inside of a 1" for 20 feet will drop the pressure only slightly, depending on your flow rate. You can do this yourself..

If you do, try this:

After you have cut the existing 1 inch pipe at both ends and fed the 3/4 pipe thru it, see if you can rotate the 1 inch pipe. If you can, and it is loose, then you might be able to remove it and put a new 1 inch pipe thru the hole, using the 3/4 inch pipe as a guide. Sort of like running one piece of pipe along the outside of another. If it works, you can then take the 3/4 back out and just bond the 1 inch in...

I've never done this, but , IF the 1 inch pipe is in the right kind of soil, this would be worth trying. At the worst, you still have the 3/4 pipe in place, as before.....

If you try this, and it works, please report back here. I'm sure we'd all like to see if it works....

Andy in Eureka, Texas

[Rebel1]

As I think more about it, maybe another approach will work.

There is 5 feet of pipe between the house and the walkway, 5 feet under the walkway, and 12-15 feet more to the manifold.

1. I dig on both sides of the walkway until all the pipe is exposed.
2. I cut and remove the section between the walkway and the house, and cover the exposed end to prevent soil from entering during step 5.
3. I cut the pipe on other side of the walkway, leaving a 1-foot "stub," and remove the pipe all the way to the manifold.
4. I connect the replacement pipe to this stub with an ordinary lawn-pipe connector that slips inside both ends. (I pour hot water on the ends of the pipe to make inserting the connector easier.)
5. I simply push the new pipe under the walkway toward the house and cut off the old section after it emerges.

Of course there will be the friction of the soil to overcome. But the break is under the walkway, so before starting the above, I'll simply turn on the water for a couple of seconds so the water coming out of the break will act as a lubricant.

Have I overlooked something?

Ray

[jamesgangnc]

Sure if you are going to do the work yourself that's not a bad solution. I'd do that. In your original post it sounded like you were going to hire it out. That's different, in that case you want the fastest solution that is acceptable. Because time =3D money when you are hiring someone to do something. If you do it yourself time is free.

[Rebel1]

The original plan was to hire out. But after thinking about one's guys suggestion for threading the 3/4" pipe though the 1" one, I came up with this approach just about two hours ago.

[jamesgangnc]

I've got a mix of 1" and 3/4" white pvc. Our irrigation slowly expanded over the years because I did it all myself. In the begining I was cautious to only use 1" for anything that had large rotating sprayer heads on it. But as time went on I realized that the 3/4 really was not as much an issue as I thought it was. Our service from the street is 3/4". You can always use smaller nozzles and run for longer too.

[trader4]

No, you haven't overlooked anything, but I think you have seriously underestimated the friction of the soil against the existing pipe. IMO, ain't no way you're gonna just pull on one end and have a new piece of pipe follow the old one.

Use a steel pipe, with one end beat closed to form a chisel type end, a cap on the other and a sledge hammer. It;'s only a sidewalk, not the island of Manhattan you have to cross.

[Rebel1]

It's leaking right below the paver walkway.

I'll find that out first-hand tomorrow, when the guy comes for an estimate.

The present 1" pipe has an inside diameter of 1.0" and a wall thickness of 1/16". Assuming the 3/4" pipe has the same wall thickness, its outside diameter would be 3/4 + 1/16 + 1/16 = 7/8". That only leaves

1/8" of clearance, but how much does one need? (Assuming everything is round, rather that slightly oval.)

[Notat Home]

If the walkway is properly built, there is probably a layer of gravel under it (possibly some gravel caused the leak) so you will have to deal with that, probably by going under it.

I had a similar situation. I bought some PVC and cut some teeth in one end. Using a strap wrench, a sledge, a garden hose (I ran this into the pipe every few minutes and used the water to erode the dirt), and some creative languaqe, I got the PVC to the other side of the sidewalk. I left the PVC in place to help support the sidewalk, and easily slid my poly through this tunnel. I used 2 inch PVC as it seemed stronger and would take the twisting and hammering, and would easily hold the one inch poly.

[jamesgangnc]

That's not a bad idea. I'd be tempted to 1 1/4" just cause it's smaller and would be easier to get through.

[chaniarts]

get a piece of 1" pvc thick walled pipe. glue a hose thread female adapter to one end. put a hose thread mail end on the other end.

dig a trench long enough on one side of the walk deep enough to get below the walk and any stone base. hook a hose to the female end. use a brass hose nozzle on the male end. turn water to hose on full blast. adjust nozzle to get a powerful thin get. insert pipe in trench and aim jet under the walk. you'll probably jet a hole under the walk in less than 30 minutes. remove both ends of the pipe and use it either directly, or thread your new pipe through it.

[Airport Shuttle]

Sounds like a fun little project please lets us no how it works out.

[chaniarts]

[Rebel1]

I excel at that.

Thanks for the excellent idea. So much for me to consider over what should be an easy task.

Ray

[jeff_wisnia]

And it runs fairly straight too.

Jeff