I recently installed (against the advice of some of you) the interior drain tile I was thinking about. It works excellent. Now it's time to pour concrete back over the gravel in the trench. Of course, I have a few questions now:
1) Should I be laying 6-mil plastic sheeting over the gravel before pouring the concrete?
2) The trench is mainly 14" wide and 36" wide in one part (had to go around main sewer line). What is the best type of concrete for this? Pre-mixed? Fiber re-inforced? I have no idea.
3) Should I be mixing my own concrete to save on money (sand, port, water, etc), considering I have about 110 sq ft of trench to cover??
- Are there any other important factors I must consider while doing this??

Thanks in advance everyone

Pre-mix cement is fine. You do not need any special type. Yes you should be pouring over a plastic membrane. You need to keep the moisture from coming up through the floor.
You will need to place a small wood strip against the wall as well. I use deck material that is 5/8 inch thick. This is removed once the cement has set.
AS far as mixing your own VS. pre-mix. 110 square feet is a lot of cement. You need to rent a mixer ot you will be doing this for quite a while.

Thanks for the help... I am wary about leaving a gap against the wall where humidity/moisture can rise up into the space. this space will be finished eventually... what is the purpose of this? and what is an alternative to leaving it open forever

also, i heard I am supposed to tape the seams in the plastic, what kind of tape is this? Nobody ever specifies.

If you have drilled the foundation wall to allow for water that may have got into the wall to escape, you need to keep this cavity open.
So the gap is important between the floor and wall. .
As far as taping the plastic. Just overlap it about 12 inches and use duct tape to seal. That will work fine.

oh, no I didn't drill the foundation wall.. I simply cut a 12" perimeter drain along the floor against the wall. I just think that moisture will rise up through the crack causing high humidity and mold problems when i finish the walls. I just assumed it would be better to seal it off, no?

To answer your question without seeing your home is difficult at best. If you live in an area of the country where radon is an issue you may need to seal it off to prevent radon from entering into the basement. Even if you do not live in areas where radon is found, I would still have a test done just to be sure. Pro-Lab in Florida has do it yourself test kits that a home owner can use to determine if radon is present. They are not to expensive but can provide a basic screening of this cancer causing gas.

Well you sort of did the job half way. However if you suceeded in stopping any water from entering into the floor you did what you need. However, most walls Not all are the source of the leakage. As they age and foundation settles cracks develop on the walls and water enters into them. If your walls had any signs of moisture such as a white powder that may have developed on them water is present within them.
You simply drill 1/2 inch holes in each block next to the foundation in each cell of the block so any water that may enter within the wall has a way to escape.

As far as construction of any finished wall within the basement. I would suggest that you construct the finished wall so there is a air space behind the wall. Then provide a ventilation system such as http://www.waveventilation.com...urce=waveventilation
There are many other brands of this system out there, but you will get the idea once you see their system and how this method works. We have constructed our own systems with a radon vent fan and de-humidistat controls and saved big dollars from the commercial systems sold such as this. This will allow for any humidity that may enter into the structure to have a way to escape before it does any damage.

Now just to understand, there are many other methods of construction of basement walls out there. Many contractors have success in building right against the walls of the basement. I however think that this is a mistake. Having this space allows for ventilation, wires to run for phone, cable etc that you may have forgot. But for most cases a place in which to provide ventilation so any dampness that does occur can be removed with air flow.