It sounds as though you have a near ideal setup. I wouldn't mess with
the basement floor til later if necessary. Your perimeter tile should
be in clean rock at the bottom of the footer. It is best to run clean
rock a foot thick all the way up the wall. This promotes drainage a
greatly reduces any possibilities of problems associated with hydraulic
pressure exerted on basement walls. I have a chart someplace. The
difference in tons of pressure or pressure per square foot exerted on
the basement walls between clean rock & dirt sand or clay fill amazed
me.
The best way is to put landscape cloth down the dirt side of the
excavation so in the future dirt doesn't leach into your clean rock.
Very few homes are built in this manner anymore because most work is
not specced and contractors eliminate this step to cheapen their bid
price.
Also many youngsters learning construction are working for companies
working on bid jobs and never learn that this is the proper method for
back filling.
You've probably seen basement walls that were pushed in? Had they been
properly back filled with clean rock, in all probability they would not
have had that expensive to repair problem.
Tract houses are never built correctly because the contractor usually
only proffers a 1 year warranty and their dirt back fill is not even
fully settled in that amount of time.
I think in your situation that you would be in fine shape if your
perimeter tile was lowered & your house was back filled correctly.
Be sure to check your tile to daylight elevation. You will probably
have to lower that tile in order to drain the lowered perimeter tile.
If your drainage tile has a lot of fall you can slope at a rate of 1/8"
per foot away from your perimeter tile til you hit your drainage tile
elevation.
On my house I installed an emergency sump outside the house. The
perimeter tiles run to the sump & the drainage tile runs away from it.
Thus if my drainage til plugs or becomes overwhelmed the sump pump
helps pick up the slack.

I am wondering what the your gutter situation. Are they properly run
away from the house? I run mine to below grade gutter boxes. These are
open on top with a removable grate for cleaning and overflow water. I
set them about 6' from the basement wall. I then run a tile away from
them to my drainage tile. Actually I have 2 ea. 6" drainage tiles to
accommodate the gutters & the perimeter tile.

Many times water problems can be directly related to poor gutter
drainage.

Another hidden concern is abandoned field drainage tiles. I worked on
one job where upon excavating the perimeter we found a very heavy
source of water. Upon further excavation we found an 8" field tile that
ran towards the house for a 1/4 of a mile. We were able to find an old
tile map that showed the field tile. With some cajoling of the
neighbors we were able to reroute the tile around the home.

Another often skipped step in construction these days is clean rock
below the basement floor. I always put 12" of clean rock & a layer of
insulation under the floor.







wrote:
Howie wrote:
What are the advantages/disadvantages of placing drain tile on top of
the footer vs. next to the footing?


TOP BAD!! been there done that water can and does come from below
footer and work its way thru your basement floor.

the underground drain to daylight is ideal, i would add a perforated
line or two around your basement under the concrete floor for best
drainage if your sump s a single point entry. this also allows drilling
or snaking line ud=nder home to be not perfect location wise.

also price backhoe digging outdoors and run line under floor tearing up
some concrete. you dont necessarily have to get the line to the sump
pit, water finds its own level anyway. just so long as it spills out
from under your home.

daylight drain is the way to go!

Been there went thru this......