draintile issue

[Peter Louis]

just inspected 1988 Rancher with unfinished basement. water seepage on the foundation; patched footing

If there are 2 different visible underground drain tiles, Could we conclude the draintile got repaired & section replaced before? any chance there were 2 different original drain tiles?

In addition, the property has septic tank. The owner told me this pit related to septic. I thought it is a sump collecting the water from lawn & drains to the building storm sump. Is that right?

Thank you

[John Kogel]

All those things you mention could be correct, but the only thing we know for sure is that water is seeping in.

I don't use 'drain tiles' to describe drains around a modern house. Call them what they are - pipes.
The black stuff is 'Big O'. You can check to see if the pipe is perforated or solid. Perforated drainpipe with downspouts connected to them are a sign of amateur work. Perforations will leak water into the soil around the foundation.

[Peter Louis]

Thanks John:


Yes, It is big "o" but I prefer to call this 1988 built plastic which is actually polyethylene rather than the paper based big o in the old days. It is always seen even in the newer building. If I were wrong, pls correct me.

I should call them perimeter drain issue properly.

[Peter Louis]

Again, perimeter drain is normally perforated PIPEs connected with down spouts in BC except in Richmond where non-perforated perimeter drain (drain tile) is allowed.

[William Cline]

Our standard way of doing perimeter drains is to use perferated ADS (brand of corrugated black flex pipe) at the base of the footing and unperferated flex from the downspouts to a connection at least ten feet from house. The photos shown may have nothing to do with the drains, other than they may be feeding subsurface water if perferated off downspouts or joined close to structure. The photos are similar to what we find when the foundation is a two pour (footing and then walls) or a block on footing foundation with no water proofing on exterior (spray on or bituthene) with proper foundation drainage away from structure. We typically dig down a foot on the foundation and look for water proofing, which should actually come above the soil surface.

[Peter Louis]

Hi, William

Did you talk about downspout drain above the ground 10' away? or separated downspout underground drain tile from perimeter drain? I did see the previous drawing of this kind 2 independent draintiles on differet elevation underground go to storm sump in North Vanouver hilly area. But now I see most contractors just connnect the downspoouts to perforated perimeter drain.

[Rainer Semsch]

This is a common problem with downspouts being connected to draintiles.
In time the draintiles will get plugged and the water has no way to go. It creates hydrostatic pressure against the foundation and will seep into the building envelope.
Considering how much water gets channelled down to the footing (hundreds of gallons during a rainstorm) and the type of backfill used it is easy to understand what will happen in two decades.
Remedy? Clean out the draintiles. If possible lead downspouts at least 10' away from house (some municipalities do not allow surface draining - too bad)
If a dig-up is necessary waterproof basementwalls and footings again and backfill with proper materials

[Rick Bunzel]

Peter,

Here in the Pacific NW we see lots of water issues. One thing you should not do is make assumption of whats connected to what and potential future performance. Report on the conditions you can see and drainage system present. There are plenty of companies that specialize in drainage systems and "dry basements" that would be happy to evaluate and determine the best way to correct the problem.

In our experience most people don't have any gutter guards to prevent leafs and needles from dropping into the downspouts. After time that stuff turns to muck and clogs up the drains. Once that happens the system just starts to back up and cause hydraulic pressure to force the water into the basement.

//Rick

[William Cline]

Good point Rick.