Replies

1. 
   kate | Oct 13, 2006 09:15pm | #1

   bump

2. 
   5brown1 | Oct 13, 2006 09:56pm | #2

   I did the same thing with a 4 plex. I'm about 3 feet deep.
   The city would not let me drain in to the sewer system so I have to pump the rain water out to the street. I have an ejector pump inside one of the garages which has worked just fine for the past 12 years. However, I would not do it again. Everytime we have a downpour (which hasn't happen in years here in central South Dakota) I worry if the pump is going to work. I live across the street and get up and check it - which is a pain. Then there is the time it rained in Jan. When I want to go out of town I always have to make plans to have it watched. Then there was the time we had no power for three days because the storm took out the main line feeding the town - and it was raining.
   To sum up so far it has worked but I hate babysitting the thing everytime a dark cloud passes over. I wish I had gotten a variance to go higher with the building.

1. 
   kazm | Oct 14, 2006 02:21am | #6

   Thanks for your input.

3. 
   CapnMac | Oct 13, 2006 11:27pm | #3

   It's possible, it just has a lot of responsibilities attached to it.

   You sort of "paint yourself into a corner" design-wise.  Really, for best peace-of-mind, and in consideration of the building's life beyond your own, you are almost required to work with water resistant/water proof materials at least up to the "flood" point.

   (You also have to remember to "carry" that answer into stairwells, etc.)

   That's achievable, since we are only talking about 4' or so.  It's a relatively fail-safe situation, if you do it that way, too (like if you had a record rain that also knocked out the power, and you were in St Bart's not avail able to hand pump a bilge pump (or that highest of capacity pumps--"a desparate man with a bucket" <g> . . . )

   Now, in a perfect world, you might consider making the driveway longer, and giving it some slope away from the garage lip, too.  That's a pretty big desing consideration to make, too--only you can assess that.

   While we are at it, you will likely have to cope with the fire & vapor seperations attached garages generally now require.  This might actually work to your favor, as that might just reinforce (or decrease the impact of) 4' of interior waterproofing.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   Learner | Oct 14, 2006 12:37am | #4

   What methods, construction techniques, materials would you use or consider to be waterproof/resilant in this type of design. I've often wondered how commercial construction deals with waterproofing many stories underground. Would they use something similar to a water proof membrane that is used on the inside of swiming pools? I think that would be impracticle. I have seen epoxy resins which are advertised as being injectable into concrete and are supposed to stop the capilary action of concrete. Would you use a large sump well with a high gpm pump and capillary breaks on the exterior of the concrete? I've often look at large excavations but it doesn't seem that they leave enough room to treat the exterior surface of the concrete walls with tar or whatever material you typically use.

1. 
   CapnMac | Oct 14, 2006 12:59am | #5

   Well, I'd likely have a block wall at least one course higher than the "flood" depth, I'm thinking.  I'd likely spec cementitious board on furring channels over that, and up over metal or wood studding, to make an interior finish.

   See, I've been to floods & flood clean-up, eliminating places for water to pool can be key.  After that, it's down to coatings & drains.  Impermeable membrane adhesed to a water-proof building material makes more than a small amount of sense.

   Note that I'm also leaning toward "no sweat with inspector" fire/vapor isolation, too--since it about breaks even for price.  But, that's also a long short term look at it, too.Occupational hazard of my occupation not being around (sorry Bubba)

1. 
   Learner | Oct 14, 2006 09:32pm | #7

   Most of the building basements that I have been in have been formed poured concrete. Why would you opt for a block wall? When you say block wall you are just talking about the concrete blocks that stack to form a wall right? I think I'd go with a poured concrete formed wall with a rubber spray membrane on the outside followed by plenum nailed to the entire outside of the walls as my capillary break. Then of course you'd have the drain tiles around the bottom of the building leading to an external sump well. I've never really taken flooding into consideration before - good thing to think about - but that is because I've only ever been thinking of one location where flooding isn't a concern. The only issue is the ground water table. I suppose my main concern is how quickly my interior sump well fills with water from the water table, I've only had the pump die twice in the 11 years the house has been up, but luckly we built our house and the one next door at the same time and built a graven ladden channel between the two sump wells to allow for a redundant backup. If my sump pump dies then the water will flow to the neighbors and vice versa - the sump pumps also have built in alarms that ring in case they fail so I've never worried about going away and coming back to a flooded basement.What impermeable membranes do you use? Are there any that you use on the inside of the wall? I like the idea of metal studs against concrete basement walls and keeping the foundation wall above ground level.MG

1. 
   CapnMac | Oct 16, 2006 06:27pm | #8

   Well, block was more out of reflex, as it tend to be cheaper in residential application than formwork for poured-in-place concrete.

   My 'concept,' such as it is/was, was to have a wall application which would tie into the rest of the construction as neatly as possible, while being functionally solid (solid in the sense of being as voidless as possible).

   This goes back to being fail-safe as a design constraint.  Which has an "elbow" or two in the conceptual design--like not being able to "walk out" at the garage elevation unless the door will seal water-tight (a difficulty greater than the good created).  That would then mean having to "rethink" mechanicals and the like in terms of what could happen in a flood.

   Ok, you are not in what's thought of as flood territory--except that you are in a location, that, whaen it rains, it does not do so in half measure.  Floods "laugh" at half measures, sad to say.

   Now, most polyethylene sheets are completely impermiable.  Which usually gets to what material the sheeting is laid in or upon.  Different water proofers use different water proofing products.Occupational hazard of my occupation not being around (sorry Bubba)