The trench may not be attached to anything. Perhaps the idea was that any water entering the wall would drain down through the floor to the ground. Instead, when the ground is saturated, water may simply start rising up through the trench.

The only similar thing I did on one new home was to run weeping tile around the permeter under the concrete floor and connected into the drains. Indeed, I may be doing that on a new home I have under way now.

Try to see if the water is rising in the trench during heavy rains. If that's the case, you might want to run weepers in the trench, but tied into your drains, as mentioned above.

To be sure the water is not simply condensation, use a dehumidifier. And double check all the usual ways to avoid damp basements--grading, downspouts, eavestroughs.

It's impossible to suggest specific solutions without seeing the entire situation in person.

Sounds like sort of a "French Drain". Some of the components seem to be missing. The system is installed along the interior wall. The concrete slab is jack hammered along the wall about 12" wide all along the basement perimeter. The dirt is removed down about 12 " or so. Gravel is laid in the bottom of the trench. A perforated pipe is laid on top inclined to a low spot( planned in advance0 and the trench is filled up to the top with gravel. Concrete is then put on top of the gravel, leaving an inch open along the walls.. The pipe is ringed around the entire perimeter of the basement. At the lowest point a hole is dug and a sump pump in a container is set up. All the pipes drain into the pump well. The sump is attached to the waste pipe and pumps out the water that gets into the basement. You can then finish the basement because the water will never run onto the floor because it's captured in the trench.
What you have sounds like a partial system.
Works well when set up properly.
Ron

lisab,

"IF"....again, IF the outside method was done correctly and IF the original problem(s)/leak(s) were DUE-to cracks or other openings/penetrations below ground THROUGH the basement wall in those areas then, NO inside system was necessary, period.

90% or so of ALL wet/leaky basements are due-to OUTSIDE cracks/pathways.

An experienced/honest waterproofing contractor will 'FIRST' DEFINE the problem, thing is...many in THIS business are NOT experts and/or NOT exactly honest.

I`ll say again, most homeowners problems/reasons are to why/how/where WATER FIRST ENTERS is on the OUTSIDE.

You state they dug down to footing, waterproofed, backfilled w/peastone etc....how do you KNOW for certain they did? lolol...many SAY they do and then do NOT, they do NOT dig all the way down, they do NOT backfill with ALL peastone, they may only has applied a 'damproofing coating'. Damproofing is NOT Waterproofing.

Some say they dig down but, they only dig-down 1-3', this will NOT solve/stop all water-entry problems-through-wall(s)....no no no.

Seems to me, they may have dug down 1-3'....and thats why they installed an Inside System along inside perimeter.

29 years we`ve been waterproofing basements, ONLY waterproofing-nothing else, have NO/ZERO customer complaints....ever. And have NEVER installed 1 inside system, not 1. Like i say, 90% of the problems are Outside, anyone pushing these Inside Systems on homeowners does so with limited-overall-knowledge of basement waterproofing and foundations.

If you search BBB, you`ll see MANY Co`s who rather or ONLY install Inside-systems have 10,25,50+++ customer COMPLAINTS within the LAST 36 MONTHS, lolol. What does that tell anyone with common sense?

You say you see/notice.. 'dampness'on FLOOR along area where they waterproofed and sounds like inside system was also done....so, that dampness COULD be there for a couple reasons. Again, IF they didn`t waterproofed entire depth of wall then, that could be why OR...they only backfilled with minimal peastone and backfilled the rest of trench with the same soil, NOT A GOOD IDEA. If they only applied a thin-damproof-coating AND backfilled with some/alot of same soil then, the settling/compaction of the same soil may have pulled down the thin-coating and RE-exposed part of basement wall/part of a crack.

OR.....the dampness could-be there because THEY tore up a strip of basement floor and left opening/gap/space between the wall and floor, this can CAUSE Dampness, doesn`t mean wall is leaking.

OR... you could have a partial blockage UNDER the bsmt floor which could cause the water-level under the floor, in certain areas, to rise up. This too could cause dampness on floor/along where wall and floor meet. Remedy for this would be IF there is a sump, have exp`d-honest plumber SNAKE tile in sump/under floor and/or, snake storm trap clean out.

Inside drain tile or baseboard systems do NOT stop/prevent water entry through ANY part of basement wall thus, can not stop/prevent mold/efflorescence/cracks widening/bowing of a wall. All they do is...divert water that will STILL ENTER, under the floor, it should keep most of the water OFF the basement floor but again, will not stop water from entering and will not stop dampness etc.

6th paragraph http://www.yodergroup.com/concrete.asp

http://www.fairfaxcounty.gov/dpwes/publications/marineclay.htm#2

http://www.askthebuilder.com/NH058_-_Waterproofing_Foundations.shtml

---Wet Basements.... read question `n answers 1 and 5 especially!
http://www.shakeronline.com/dept/building/FAQ.asp

why foundations fail

http://www.bobvila.com/HowTo_Library/Why_Foundations_Fail-Foundation-A2095.html

http://www.askthebuilder.com/015_Exterior_Foundation_Wall_Waterproofing.shtml

Mold? http://www.des.state.nh.us/pdf/MOLD_in_Homes_Web.pdf

efflorescence http://www.marshallconcrete.com/41

radon, how does it ENTER?
http://www.epa.gov/radon/pubs/physic.html#Character

http://radon.utoledo.edu/remedy_mech.html

insects/termites enter through openings/pathways on outside

http://www.utoronto.ca/forest/termite/tips8.htm

Basement BACK-ups upon FLOODING...lateral line etc

http://msdgc.org/downloads/wib/common_causes_wet_basement.pdf

Please, licwaterproofer, tell me where to find someone like you to come out and give me an estimate on my mother's basement. I have had two estimates, one was kind of pushy, the other not, and both were expensive and included work you have said is unnecessary. I can fix the downspout thing, but I sense there may be more going on with the basement walls that they may need outside repair as you have suggested.

Mary