penetrations through block wall

[davidj]

Our 20x30 is now officially 16" high, given that I've laid the first two rows of concrete blocks for the foundation wall.  Only another 21' to go!  But this means I've got to the stage where I need to get the drain (4" ABS), water (1" PVC) and well pump wire (3/4" plastic conduit) through the foundation wall.  What's the right way to do this?  I can get drills for the small pipes, so I don't need to cut the blocks for them, but should I cut the hole for the 4" pipe before laying the block or after?  Do I need to sleeve the pipes where they go through?  I assume I do all of this before grouting?  And then how do I make it water tight, given it's below grade?

[glenn kangiser]

Do whatever works for you.  I have a 6 inch round diamond hole drill  I would drill through with but lacking that I would just get a diamond or abrasive masonry saw blade - notch out a big enough square - hit it with a hammer - put a pipe sleeve wrapped with cardboard and grout around it making it as pretty or ugly as I wanted.   Before grouting is easier.  Take the easy way.

If water tight is necessary use the same waterproofer you use on the rest of the wall.  It will all leak if not sealed.  May not be necessary given proper drainage.

[MikeT]

When I was cutting my hole through my foundation for my dwv pipe, I seemed to have knack for hitting the rebar.  I needed to hit a certain place for my pipe to connect with the septic tank correctly than that was right where the rebar was.

I do not know that there is a moral here, just my experience.

mt

[glenn kangiser]

Murphy's law, Mike. 

I have help for you in some cases.

Carry a spare - you will never have a flat. 

Wash your tractor engine regularly - it won't break down.  They only break down when covered with dirt and oil. 

Order an extra board - you'll never need it unless you order the exact amount.

Don't put a new tire on a trailer with a bunch of old rotten ones.  That's a sure way to get a sidewall puncture on the new tire.

A new trailer tire will always blow out before the one with the cord hanging out.  (Expansion of the above thought).

I have more. I am a fountain of knowledge.

[TheWire]

I would leave 1/2 of a brick out.  Put your sewer line through it, shim it so it doesn't rub the block then fill it expanding spray foam.  I started with hydraulic cement but finished with the foam because it was too hard to fill the nooks and crannies with the cement.  Then seal it from the outside with whatever waterproofing your using on the walls.

Jerry

[rwanders]

Best practice is to always use sleeves to run pipes or wiring through block walls----if you ever have to replace or repair them you will quickly find out why. Most installations use a rubber gasket which have hex headed "expanding nuts" which will produce a watertight seal---should be available through most building suppliers or plumbing supply houses. The sleeves are grouted in and the expanding rubber gasket seals the annular space between the sleeve and the pipe ore conduit. Use abrasive hole saw for smaller sleeves and leave block or part of block out for larger sleeves.

[n74tg]

If you decide to go the diamond blade route, WalMart carries a diamond blade that is about half the cost of the ones at the big box stores.  After I wore out the expensive one, it's replacement came from WalMart and it has performed just as well as it's expensive brother.

In fact, even if you choose not to go this route, you still need a diamond blade in your toolbox.  It has LOTs of uses; you will be glad you bought it.

[davidj]

This is what I ended up doing...

For the water supply and electrical, I drilled through the block with an abrasive hole saw and used regular PVC pipe 1/2" larger than the supply.  And of course I hit the rebar when I drilled (which requires a reasonable level of stupidity when the blocks are still ungrouted!!).

For the waste pipe, I looked into 6" PVC and they wanted $45 minimum at the one place I could find it.  Then I went to Urban Ore, our local recycled building materials store, and got a couple of feet of 5" plastic electrical conduit for $2!  I removed half a block of the wall, then used a jigsaw to cut 5.5" holes in 2 pieces of 3/4" ply.  I screwed this into the block on either side to hold in the grout, then added four 8" form ties at the corners for good luck, and slid the conduit through.  The pour is on Saturday so we'll see if it works then...

[glenn kangiser]

You could use about anything that will block the concrete out and come out-- coffee cans - planter cans - a round of a tree with cardboard wrapped around it to make it release- rolled sheetmetal filled with earth-Ice cream containers -  sand  -cardboard  duct taped together etc.  It doesn't have to cost money as it is just making a hole. 

Make sure the filling is solid enough to stand up to the pressure of the concrete.  I sometimes fill a box with sand and set it just under the surface for a tub fitting or toilet to fine tune it after the pour.  Leave it about 1/2 inch low then finish right over it to make it easy.  Come back with a hammer and break it out when you are ready to plumb, etc.