Big "O" perimiter foundation drain pipe

[deejoe]

When installing plastic ( 4" big "O") drainage pipe around the perimeter of a home's basement foundation, it is suggested to use the 4" plastic pipe that has the PERFORATIONS ALL AROUND the pipe along the perimeter of the foundation, and then finally use plastic pipe with no perforations to carry it away to the desired drainage area.

My question is; how does this allow any water to be carried away from the perimeter of the foundation with all these perforations? you would think that because of the many perforations around the pipe that it would just allow the water to just sit there andfinally build up around the foundations perimeter footings and then finally enter into the basement floor. But it don't...
Any explanations as to WHY this happens,..... anyone ?
Thanks for any reply.

[joed]

The pipe even full of holes is a channel for water to flow. As the water level rises and water enters the pipe from holes the water will flow through the pipe and out the pipe that lead to the drainage area.

[deejoe]

thanks for the reply. I realize that eventuallythe water will flow, but with all the holes all around the pipe why don,t it just saturate the area and spread out? What is the reason for this?

[scuba_dave]

Perimeter drain is to allow water to drain off
If it doesn't have holes, water can't enter the pipe to drain off. When the ground is fully saturated the pipe fills up & water drains off. Water will follow the path of least resistance. Since the pipe is open water will flow more readily thru the pipe. If a portion of the pipe is in a drier area then yes some water will then saturate that ground

But these are made & designed for large amounts of water when the ground is already saturated

[joed]

Think of the pipe as a covered ditch. As water enters is simply flows by gavity down hill. The non holed drain pipe is an extension of the ditch to allow the water to flow away. Without that extension to a ditch or sump pit the water would just build up. Without the holed potion around the perimiter the water take a long time to filter through the gravel only to the drain pipe.

[pushkins]

Easy explanation....water wants to be in the area with no resistance, it would rather be "in" the hollow pipe than in the soil and rock around the house, once "in" the pipe, gravity will guide it on it's merry way to a lower place.

Just like wells work, when you bore a well you (for most of us) aren't drilling a hole into a huge chasm of water, your just drilling into the water table which is basically very very very very wet soil, when you drill into this wet soil the water wants to be "in" your drill hole (no resistance).

Same situation when you want to help dry out land, dig a big pond and let it fill up with water, the water that was causing your soggy soil now would rather be in the pond because of a lack of resistance.

[mark5]

The 'waves' go up and down. Or postive and negative relief, depending if your looking at it from the outside or inside of the pipe. So from the outside, water wont want to sit on top of A, it will roll down, into X, and then seep into the pipe. Once inside the pipe, it wont sit on top of the rounded Z, it will fall into the Y, where there is no perf. When you look at the perf drainage tile from the outside, the perfs arent on the high points, theyre only on the low points, so water outside, will generally want to fall into the pipe, and water inside the pipe, will generally want to stay there. Of course there will be some loss along the travel down the pipe, but generally its engineered to take more water in then it lets out.

[deejoe]

Mark; Thanks for the reply, but the holes are ALL AROUND the big O pipe

[mark5]

Sorry, my mistake, I've seen the term used as a generic description for your standard perforated corrugated tubing, you could pick up at Home Depot or where ever. After a bit of searching for more specific answers, I found a few things like this: "dozens of homes flooding owing to problems with Big “O” pipe approved by the city", and heres another, "Do you have Big O pipe as a perimeter drainage system? This corrugated/rippled black 4" pipe is available in coils and was used for about ten years between 1975 and 1985. The water entered the pipe through very small holes located throughout the pipe. This system had a few problems and as a result is not used today." But I couldnt find a close up picture of it, it looks like your standard perf. corr. drainage tile, except there are more holes?

[Bob999]

Here is a link for Big O drainage pipe.

http://www.bigodrain.ca/prod_tubing.php

[AllanJ]

Somehow I don't think it matters whether the holes in the pipe go all the way around as opposed to being all in a row, except for the total square inch area of all the holes.

When the level of the water in the saturated soil rises above the level of the first row of holes, water will seep into the pipe and that water will flow quite rapidly to the dry well or pump pit.

[Wgoodrich]

The weight of the water and readily desire to flow to least resistance is the key to the knowledge you seek.

As an experiment take a 5 gallon plastic bucket and cut a hole in the bucket. Insert a 4" plastic pipe in that hole and holding that 4" pipe level.

Now take a garden hose and fill the bucket. The water level will never rise above the inserted pipe. It will flow down that pipe till the water is level with the bottom of that pipe. Stick a dozen hoses in that same bucket and the flow will increase. If you put enough hoses in that bucket so that it filled with water the water would flow full scale out that 4" pipe due to the pressure created by the water that is located in the bucket above that pipe. The higher the water level the more pounds of weight of the water is created thus pushing the water out that pipe by the weight of that water above that pipe.

Now picture the subsurface water table rising above the bottom of the Big O pipe located at the footer of your basement. As the subsurface water rises the weight of the water increases the pressure pushing water into that pipe till the subsurface water lowers to the bottom of that pipe. Only then will the water stop flowing.

Now if you have a small rain and the subsurface water reaches the bottom of the pipe then a principle of water will level itself kicks in. For an experiment take a cake pan and pour water in the center of the pan. As you add water the water will spread keeping it level. This is the common flow in that big O pipe in small rains. When big rains hit and the subsurface water rises above that Big O pipe around the footer of the basement it will flow faster due to the pressure of the water to flow by the weight of the water above that pipe.

Hope this generic explaination helps

Wg

[Fischer]

If you haven't already don't use the corrugated big "O" pipe. Use 4" PVC with 2 holes on the bottom. The Big O pipe is certainly not worth the money you'll spend when it finally clogs up with silt and sediment.