Foundation footing drain construction
When constructing foundation footing drains, if they are required, due to water that comes in low in the grade, near the foundation footing, advise your contractor to do so creating a grade for the system.
Do not lay the perforated pipe flat on the outside of the foundation pour. Do not use the perforated pipe with a sock over it, and just backfill it with dirt.
Create a french drain at the lower level where your footing is, by constructing an engineered grade of at least 2″ per 10 lineal feet or greater within the french drain constructed, and backfilled with 3/4″-11/2″ river rock covered with 1 layer of weed cloth shiney side up.
Perforated pipes that contain filter sock or wrapped up in landscape fabric or road cloth left over clogg easily. I recommend constructing footing drains that have a grade, and slope deeper around the home.
Many times it is better to divide this work into sections that each have their own vent, rather than laying one pipe flat, all the way around the footing of the home. This flat method seems easy, but you have too many lineal feet and not enough grade usually. The footing drains must slope to a daylighted vent, pump, or a drywell, whatever is most appropriate.
Do the math envolved so you know that the water is not going to just sit on the foundation footing in the pipe when filling up. This is why you need a grade to flow this water away from the foundation footing to prevent wet crawlspaces and basements.
Flat constructions will likely leave you with hydrostatic pressure, which is what you are trying to avoid by the construction of the footing drain, which is really a special type of french drain.