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|03-28-2010, 07:56 AM||#1|
Join Date: Mar 2010
Location: Lansing, Michigan
Posts: 130Rewards Points: 75
Installing French Drains
I have poured over this site all morning and have read many topics that are familiar with mine. Albeit mine is slightly different. I have purchased a 1200 sq. ft home with full basement. Location south central Michigan. Built in 1973. Block wall basement. There are no cracks in any of the walls. There are two sump pits located in the basement. One is an overflow pit that connects to the other via pvc tube. There is a clay tile coming into both pits. The pits are situated East to West. The clay tile to the west(primary pit) has water running non stop into pit. I would guess 1-2 gallons a minute or more. East tile not so much mainly heavy rain or snow melt. Both pits have pumps although one is a back up. I have not yet closed on this house and have been checking pits and pumps after each rain session to guage reaction. Lock box on house allows this. This is an empty home that was foreclosed on. As is condition. Basement guy (from basement systems) said I have an outside tile leading in. Relieving hydrostatic pressure I assume. I will have him install a new triple safe sump system with battery back-up. This is a single and larger system. Should the power go out I will have ten hours to return home and fire up generator. He believes I am on some sort of spring or artesian well as the water coming in is cold and clear.
When the home was vacated and the power cut the basement flooded to about 50 inches or so. That's how much water comes in. I have been in contact with neighbors and their pump runs quite frequently as well. Apparently the basement has flooded severely 4-5 times since '73 apparently due to power outages. It has been remodeled several times. I know you are all thinking RUN!!! But the house is cool the property is great 4 acres and country setting. Just what we are looking for. Bid on house for the price of a suburban and got it. I understand that I have water issues. I understand that if I don't have a plan in place when the power goes out or a pump fails then the basement will flood. Shame on me if I let that happen. So here are my questions.
I can see the bottom blocks on one side of the basement are darker than others. This is the side where the East tile does not run much. The seam on the floor/wall is wet and there is a small puddle on the East wall. It is seeping thru blocks I assume. Perhaps the tile is damaged or blocked?
I can not afford (at this time) for a pro install on an interior french drain. $5500. I will be spending $2350 on sump sytem already. Can I install the DIY french system called Border Patrol or Squidgee system? Will it work by drilling holes into block? I am afraid there is so much water behind the walls it will come pouring in. This system is about $600 I can not do a gravity exterior tile sysyem due to grade it has to come into house and be pumped away.
The house has a bad negative grade around two sides of it and I will be fixing that as well as downspouts and the like. The previous homeowners were pigs and very dirty people as evidenced by the condition of the house. I spoke with them and they say they let it go because they were tired of worrying about the water. Although they lived there for about 12 years. Anybody that worried that much would have fixed the gutters, downspouts and the horrible grade issues. There is also a hole in the sump outlet line because I can hear it sucking and gurgling about 30 ft from where it exits home. No check valve on pipe riser either. There is a 10 inch grade issue sloping towards the house. I can not believe most anything they tell me because the simple fact is they didn't care and they were too lazy. (ie. embedded dog doo still in carpet).
Can I get a few professional opinions on this from someone not selling me something?
I also plan on digging a pond out back and using some of the soil to raise the grade around the entire home about 10 inches. I will be installing a "dry creek bed" around 3 sides of the home to carry runoff away from the home and the pumps in the basement will run to the newly dug pond to help keep it filled if need be or have a diversion valve to run it out to the road and into county ditch/drain.( I am a former landscaper). The house does sit on a "knoll" compared to the rest of the property.
Sorry for the long post just wanted to give as much info as possible.
|03-28-2010, 04:25 PM||#2|
Join Date: Mar 2009
Posts: 5,257Rewards Points: 4,094
A French drain is simply a stone filled trench, named after a Mr. French who developed the technique for draining land back in the 1800's. Personally, I use the term perimeter drain as it is much more descriptive. The purpose of a perimeter drain is to collect groundwater and cause it to flow either away from the property by gravity, if that is possible, or into a sump pit where it is pumped away (your case).
An exterior perimeter drain is generally preferable to an interior drain. Interior basement drains are commonly installed because the house has a drainage problem, and it is too costly or difficult to install an exterior drain. However, you may be able to install an exterior drain yourself, with possibly a Bobcat with a small excavator on it.
The typical design is to dig down to approximately one foot below the footing, install a 4 inch diameter perforated PVC pipe in a gravel bed. The pipe is generally wrapped in filter cloth to minimize the intrusion of silt. The 4 inch pipe is placed around the entire house, and connects to the sump pits via a solid 4 inch PVC pipe at convenient locations. The perforated pipe is typically laid flat, with the holes facing down. The perforated pipe is backfilled to the surface with 3/4 inch stone or similar granular material. This creates a free draining zone around your house that collects surface water and allows it to flow rapidly downward to the pipes, where it is collected for draining into the sump pit.
Typically 4 inch pipe is adequate to collect groundwater, in rare cases you need a bigger pipe. The idea is that the groundwater under the house is kept approximately 1 foot below the basement level, so of course the sump pit has to be deeper than 1 foot below basement level, and the float must be set to turn on when the water reaches approximately a foot below the basement slab. You can cut it closer, say 6 inches below the slab level, which will save a little money on pumping costs.
As I say, you may be able to install such a system yourself. The main costs are the excavation, pipe and filter cloth, and granular backfill. You already have the sump pits installed, and the pumps, so there is no additional cost there.
The two systems you mentioned I am not familiar with, so I can't comment on whether you could put them in. An interior installation would require cutting through the concrete and installing essentially the same system inside the basement, which may also be doable, the difference being that you would need to either break the concrete with a jackhammer or sawcut it.
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