Rake it smooth and put down some big cardboard.

Even though there is an airspace, might even consider some plastic to keep ground moisture from traveling upwards.

I'm wondering what, if anything, I could or should (or shouldn't) do to insulate the bottom of the house.

http://forums.pelicanparts.com/uploa...1620230008.jpg
Unless the red one on the left is a wet vent. It will work and meet code since there is a clean out in line with the waste line. Would it have been better with an "L"? Sure.

The one on the left is waste/drain from bathroom sink, shower, tub, and toilet.

The 90 on the left is fine, but not the Wye it discharges into.
Replace 90 with 45 and replace Wye with long sweep Wye.
Then replace right Wye with long sweep Wye.
Not difficult but still.

Are those 6" pipes? In a house?

No real idea how big they are. They probably aren't 6". The "nut" on the end of the clean-out cap was a little smaller than 1.75". So looking at the photo, I'm going to say the cap was 3", so I guess that means that the ID of the biggest pipe was 3".

If I said 6" before, that's my mistake. I don't have tons of PVC experience and always forget that it's ID, not OD, and then estimating size from 10-15' away in the dark is not my strong suit.

I think it looks like 6" from the pics. I just think that is big for a house. But maybe you like your salads and beans. Good luck

Looks like 4 to me. Can't believe we're on page 4 on a subject about poop pipes.

Just remember, sh.t don't flow uphill and the liquid can't outrun the solids or the pipes get plugged with poo.

...and hots on the left, colds on the right.

I would bet its a 3" line.

How much are we betting?

Only reason I think it's 4 is the 2" coming into the back side of that Y in the pic above that then hits the 90 and goes to the pipe in the ground. Looks like 4 to me.

At least the pipes I have been dealing with at the "country" place are out in the open when you dig out around them to expose them. Here I was adding a run to another building and taping into the main where it comes out from under the slab. Had to dig very carefully as there are all the other utilities buried there too. Fresh water, propane, power, telephone and TV coax going to another building. I stuck a long sweep elbow in the existing pipe to tap into. Also added clean outs on both the black water and gray water lines for good measure while I had everything exposed.
http://forums.pelicanparts.com/uploa...1620413048.JPG

Crawl under and measure it before this escalates !

Hahahah - middle aged guys on an internet forum, I'd expect nothing less. And I'm just as guilty as the next guy, so I'm all in at 4".

We gotta make sure Steve doesn't bet though and keep him from being influenced by BK because Steve said he thinks it's a 3".

Hahahah, don't hold your breath. I'm pretty unlikely to get back under there unless I really have to.

You have to! This must be settled!

Please!