Who does Crawlspaces?

Loganwayne

Loganwayne

#BTL
Joined
Feb 15, 2013
Location
Clyde, North Carolina
Who was It on here that does encapsulated crawlspaces? I've got a question about a job we have done and would like to ask someone who has more knowledge than me.
 
I'm just a welder, I don't know these things anymore. ;)

Take it away .
 
Bringing this back up to the top.

Had a waterproofer give us a quote to deal with some water intrusion issues in our crawlspace. He recommended digging a french drain INSIDE the crawlspace to channel the water to a sump.
This seems... backwards to me. I would think you would want to deal with the water before it penetrates the foundation?
Am I just thinking too hard about it?
 
Semi related question. Do I need a foundation drain at all? My footings went down last week and the foundation is going up this week. My GC has a perimeter drain priced in but the more I look into it I'm not sure I need it. My lot is pretty flat, maybe 8" elevation change from front to back (1 acre). It drains very well, I have very sandy soil. When we dug footings on Monday the deepest point was only a little wet after several inches of rain the week before. I will only have a crawlspace, no basment. I'm already planning to do a sealed crawl (haven't forgotten you @Mac5005) The more I read it seems like perimeter drains are more for all basements and existing crawlspace's with moisture issues.
 
I think it’s better to get rid of water before it gets into crawl space or basement. But there are a lot of variables that may make alternatives a better choice. There are two types of water available in foundations. Surface water which is easy to see. Subsurface water which can be very difficult to diagnose and frustrating to manage. I say manage because that’s all we can do with it.
Surface water can be managed with landscaping. NC codes provides for a positive slope away from a foundation. Gutters and downspouts can collect water which will help keep rainwater off of porches,entrances, sidewalks, and windows. The termination off downspouts often creates another problem by draining a lot of water at one spot next to the foundation so maybe downspout extensions or a drainage system is needed. Hard surfaces such as driveways,sidewalks, and patios often do not drain well providing addition concentration of surface water.
Subsurface water can be the water table which can change a lot even levels of many feet. The drainage capability of soils has an effect but it’s possible for water moving downward in soils to be slowed or stopped by rocks or different soils to create pressure to push the water up elsewhere.
A lot of foundations are a single row of bricks. The first courses off the footings are often laid without mortar between some of the joints. I’ve seen bricks turned up on the face exposing the holes in the bricks. A simple masonry wall is not waterproof.
If the elevation inside the crawlspace or basement is lower than outside I would make provisions for sealing the walls below grade and install an exterior drainage pipe below the level of interior soils. Termination of drainage pipe would be to daylight or to a sump pump.
If the elevation is the same in and out good and proper exterior drainage as mentioned above is sufficient.
Now if we are dealing with an existing structure with mature landscaping and soil levels that have increased over time along with trees and shrubs root systems growing it becomes much more difficult and expensive to do exterior drainage systems. Who wants to redo a good concrete driveway or tear up a brick sidewalk or regrade their yard ?
A interior drainage system may manage the water at a substantially lower cost and quickly. When I evaluate a crawl space or basement regarding water issues I first try try to determine the source and then the volume. What I need to decide is the water coming in or going out at a location and with volume enough to cause soil erosion which may jeopardize the ability of the footing and foundation to support the building?
Sometimes sources of water from outside can be altered to reduce the volume or entrance location. If an interior system is judged to be sufficient it can be effective, low cost, and quick.
 
awheelterd said:
Do I need a foundation drain at all?
Click to expand...

I would rather have one than not. Run the pipe to the low side and daylight through a pop up emitter/dry sump. If grade runs toward the house anywhere, pipe those downspouts to the low side and away from the structure.
 
shawn said:
I would rather have one than not. Run the pipe to the low side and daylight through a pop up emitter/dry sump. If grade runs toward the house anywhere, pipe those downspouts to the low side and away from the structure.
Click to expand...

I'm not against putting it in necessarily, I'm just not sure if my grade will make it effctive. With the top of the footing already being a few inches below grade, I'm not sure I have enough fall before I get into the woods for a popup emitter to work. I guess that leaves me with a sump pump. I need to borrow my buddies transit and shoot some grades to know for sure though.
 
awheelterd said:
I'm not sure I have enough fall before I get into the woods for a popup emitter to work
Click to expand...

You may not. I'd like to see the top of the emitter below the bottom of the perf pipe, but it should be sitting in a dry well regardless (the bottom of the emitter drains into the dry well so that it isn't holding water all the time). If the dry well is big enough/drains well enough, whatever water gets caught in the pipe will end up in the well. Either way, it gives you an inspection point. I like that.
 
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