Trenching - worth trying for a novice?

[Nic3456]

So I'm building a new house and thinking about doing the trenching myself.

Water - 600/ft (quoted $6.50/ft due to needing to be 48" deep) - including pipe
Gas - 600/ft (quoted $2.80/ft buried 30" deep) - including pipe
Elec - 200ft ($2.80/ft,not sure of depth) - elec co provide wiring and charge me separately.
In my area we also have to run the downspouts to discharge 6' away from foundation but can also do this via above ground (would just be nice to trench if I have trencher available)

It's a lot of trenching,but appears I can rent a ride on machine that will go down to 48" for about $300/day. My land is flat with no trees and fairly hard clay about 30" down based upon soil test. I wasn't going to consider doing it myself until the water line quote came in. Something else to consider is the electric lines run E to W (to the transformer) while the gas/water will be running N to S from the road. Im assuming I will just need to hand dig when passing through that area?


Thoughts?

 

[hghvolt]

I've learned from years of doing underground electrical services that you need a trencher that will dig 12" deeper than the lowest depth you want. The chain will fill about that amount back in as you dig.

 

[oldpilgrim]

Beware of large rocks. That can change your plans quickly.

 

[Nic3456]

I've learned from years of doing underground electrical services that you need a trencher that will dig 12" deeper than the lowest depth you want. The chain will fill about that amount back in as you dig.

Are you saying I should dig it deeper to account for that or just get one capable?

 

[EddieWalker]

Water is going to need a smooth bottom on your trench, which means a lot of shoveling to get it cleaned out. Trenchers only remove most of the dirt, there will always be some on the bottom that needs to come out. Gas doesn't care if it's a long roll without any joints. Electric doesn't care, but the trench is the easy part. Getting your wire inside the conduit is where all the work is.

What type of pipe are you using for water? Type of pipe really depends on your soil type. I would talk to your water department to find out what they recommend. I have red clay that is fairly expansive. When the ground is wet and freezes, it moves a lot. When it dries out in summer, it moves a lot. Water lines of any length need to be gasketed, or they will tear apart over time.

With my riding trencher, I can dig those trenches in half a day. When everything is in place, it will take twice as long to fill and smooth out the trenches with the blade on the front of my trencher. Depending on thee type of pipe you use for water and conduit, that could take a full day to install. If you have to clean out the bottom of a 48 inch deep trench with a shovel, that could take a full day or twice that long.

The savings is there, but there is a lot of work that you will be doing and it's all very physical work. If you get it wrong, you can't call them back to fix it, you'll be responsible for what you do.

 

[Creamer]

Eddie you are just too darn practical.

I tried it myself once and it would have been great if I hadn't found that the previous owner had used a lot of fill that included large chunks of concrete, i.e. back the trencher out and break the concrete and then go again until you hit the next one. I rented a walk beside Vermeer trencher which was a beast - it dug really well even in the mess I got into.

To get a trench 48" deep it is helpful to have a longer beam so that it is not so straight up and down as it cleans the trench much better. The bottom needs only to be smooth and no rocks or hard chunks that would pierce or break the pipe - it does not need to be totally cleaned out. If you are in clay and it is really dry you may want to water the path a few days ahead of time to soften it.

 

[POC]

When we trenched in a bunch of water line my dad made a tool to clean the trenches out.
He took one side of an old post hole digger and bolted it to the end of a 10 foot piece of 2x4 ripped in half. Cut the end at about a 30* angle. Bolt the post hole digger piece on the angle. You can stand outside of the ditch and drag the dirt toward you. It made a world of difference for us.

 

[Nic3456]

Water company's suggestion is USE 2-INCH SOR 21 PVC PIPE WITH A WORKING PRESSURE OF 200 S.I.

 

[C4Ranch]

I trenched several hundred feet with a 45hp ride on trencher. Had rocks so I first cleared them with a subsoiler.

Had electrician do the electric then I did the water.

Was a lot easier to backfill with the trencher front blade but I had already turned it in by the time I finished it out so I used my box blade and pushed in by backing into at an angle.

 

[EddieWalker]

Water company's suggestion is USE 2-INCH SOR 21 PVC PIPE WITH A WORKING PRESSURE OF 200 S.I.

I'm guessing SOR is a typo and it should be SDR 21. I've never used that. I've always gone with gasketed pipe when going that big or bigger. Since it's a solved welded pipe, or glued together pipe, be sure to follow the instructions to the letter on what to use to glue it together. My guess is that it's similar to Schedule 40 PVC, but I don't know that for a face. When working with Schedule 40, you have to use purple primer and heavy duty clear cement. The primer conditions, or softens the pipe. Then the cement melts, or welds it together.