Basement egress windows
I am currently getting bids for interior drain tile and the addition of a basement egress window. Two companies I have spoken with have indicated they will dig down to the footer under the egress windows repair any cracks, and refill with washed rock within 8″ of the bottom of the window opening, install fabric and then another 4″ of washed rock. This method in essence will tie the drainage under the egress into the perimeter drain tile system.
The 3rd bid I received who has 30 years of experience indicated he does NOT like digging down to the footer as he believes intentionally integrating the drainage of the egress window into the perimeter draintile system is not a good idea. Instead he digs at a 45 degree angle from the bottom of the window opening away from the foundation. This creates a “low spot” that is filled with washed rock 3-4 ft out from the block wall, in which water would collect in the event of a heavy rain event and the dissipate into the soils below
It makes some sense not to intentionally integrate the drainage of the egress into the perimeter tile as now you are potentially introducing water into the system that may not make it to the sump basket unless you have a very heavy rain.
Input suggestions on which methodology to go with? Located in Zone 6A Minneapolis
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Replies
is the perimeter drain tile system you mention, different from the new interior drain tile system?
No exterior drain tile currently exists. The house was built in 1938. My understanding is the drainage under the egress window will be integrated into the interior perimeter drain tile system. so that in the event water collected into the egress window well it flow into the perimeter drain tile system. If enough water collected, it would flow into the sump basket.
Hopefully that makes sense
Hmm...I'll be interested in seeing what replies you get. I am also in Minneapolis, but I don't have an exterior system or interior sump. I was thinking that your second option (slope away from the house w/ rock bed) was the best for me. Would you mind sharing what the ranges were for $$ for the quotes?
3-4K with the integrated approach closer to 2k for the 45 degree angle approach. Send me a email if you want the names. Also the 2nd option would be the approach of course if one was not considering an interior drain tile system
how do they integrate the exterior crushed rock with the crushed rock of the interior perimeter drain? Are they digging under the footing so there is a path for the water to flow?
As for the 45 degree angle approach, it could work too, depending upon what type of soil you have and how much rain you get. If the soil is clay, water won't drain very well. What is the ground level on that window side? Does the ground slope to the window?
FYI. I am no expert just thinking of the questions I would ask.
MS,
To a large extent this depends on your appetite for risk. Integrating the drainage with your perimeter drain is the safest bet. The window well and surrounding grade should be installed to guarantee that only the rain that falls directly into the well moves down to the footings. Apart from the drain rock, the well should have a vertical perforated pipe with a floor drain cover on the top which ties the systems together.
The 45 degree rock pit relies on a constant low water table and being large enough to hold the rain from any storm that may occur. It should also have a perforated pipe and drain cover so that if the surface of the drain rock becomes impermeable due to debris building up, the well still works.
Malcolm, I agree, integrating the two systems together is the best but there as yet been no answer as to how the window drainage is going to tie in with the interior perimeter drain. You can't count on there being any crushed rock beneath the footings to act as the path between the interior and exterior. Even then, you will have to count on pressure forcing the water underneath the footing and then up into the interior perimeter drain tile.
Aaron, The connection is made with solid pipe run through the foundation wall above the footing. The pipe connects with the perforated vertical run from the well. The rock gathers the water, transportation is best left to piping.
Not sure this is relevant to your particular situation, but basement egress window kits are available that include the window, the window well, metal grate and a clear plastic cover. Regardless of the drainage method you use, the plastic cover can be put in place in the event of heavy rain.