Basement Drainage

Molo · Aug 8, 2007

I HAVE TO EXCAVATE THE EXTERIOR Perimiter Foundation Of A House> It Is Very Long> If I Go To The Same Height (an Inch Below The Top Of The Footer) Along The Length Of The House I Will Have A Level Trench> Is This How Its Done> Im Wondering How The Water Will Flow Out>

Excuse The Typing> A Popsicle Melted On The Keyboard

Tia
Molo

Markts30 · Aug 8, 2007

1. How deep is the excavation going to be? 1-2'? 3-4'? over4'?
This is important because of the labor involved and the risk of trench collapse after/during excavation....
2. Do you have a basement sump for groundwater? If so, can you tie into it easily (minimal concrete cutting/breaking)?
3. Is there natural drainage (ie a slope you could "daylight" the drainage pipe to so the water will flow away from the structure?
4. Are you familiar with drainage piping/"weeping tile" installation?

Lots of things depend on the type of structure, availability of sumps and pumps, depth of the footing, slope/natural drainage of the land and ability of the worker...

Sponsor · 2022-01-29T12:20:58-0800

Molo · Aug 8, 2007

Hello<
Thanks For The Response Markts

!> One Side Of The House Is Three Feet< The Other Side Is Six Feet To The Footer

Two> There Is No Groundwater Or Water Table Problem Here< It All Comes From Rain Coming Down The Hill< There Is No Existing Sump In The Basement

Three> There Is Definitely Natural Drainage Daylighting Will Be Easy

Four> I Am Familiar With Several Drainage Piping Products> I Just Dont Know What The Best One Is

Tia<
Molo

Jadnashua · Aug 8, 2007

If the dampness in the basement is only coming from the gutters, run them into a drywell and maybe something like a leachfield if you think you'll have that much at any one time. In fact, if you regularly have watering bans and you can afford the space and time, you could run it to a cistern and use it to water the yard and plants.

Molo · Aug 8, 2007

Hi Jadnashua<

The Moisture Is Without A Doubt Not From Gutters> They Are All Well Directed Away From The Building Downscope> The Moisture Is From Rain Surface And Subsurface Runoff That Comes Down The Hill And Hits The Foundation

Molo

Jadnashua · Aug 9, 2007

Two cardinal rules about surface water, drainage around foundations: You need the ground around the building to be graded away from the foundation, 6' is sort of the desired minimum, and control significant runoff towards it. That can be done with swales, ditches, or other landscaping features. The simple expedient of running the gutters out away from the foundation, and preventing surface runoff from running to the foundation should alleviate a lot if not all of your problem.

Markts30 · Aug 9, 2007

molo said:
!> One Side Of The House Is Three Feet< The Other Side Is Six Feet To The Footer

This comment would make me suggest you look at a landscaping solution as was already mentioned...
It will be a lot cheaper and safer...
Any excavation as deep as the one side of your house would require either shoring or sloping the sides...
this would result is lots of $$$ and time...
Your best bet is the landscaping route...
If you choose to do the foundation drain, please hire a pro to at least come and advise you before you start, and, if you decide not to shore/slope the trench, make sure your life insurance does not have a stupidity clause...LOL

Old Dog · Aug 10, 2007

markts30 said:
If you choose to do the foundation drain, please hire a pro to at least come and advise you before you start, and, if you decide not to shore/slope the trench, make sure your life insurance does not have a stupidity clause...LOL

Thanks alot! I'm still cleaning up the coffee I just sprayed all over my screen!!

Molo · Aug 10, 2007

Water Drainage Video

LOOK AT THE BOTTOM OF THE WALL< THERE IS A FAUCET COMEING OUT THE CONCRETE BLOCK THAT I DRILLED A HOLE IN THIS MORNING> I DRILLED A `1/4" INCH HOLE IN A FEW BLOCKS THAT WERE WET AND LOOK WHAT HAPPENED

Jimbo · Aug 12, 2007

I am not a builder...but I have this question: Is there an issue with excavating that deep on the outside of the foundation wall? In other words, is the fill supporting the wall, to where bowing or something could occur? Just asking. We don't have basements or foundation walls like that....everything is on a slab!

Mr_Pike · Aug 13, 2007

You don't have to install a drain tile completely around the perimeter of the home.

All you have to do is create a depression in the water table by either installing one or more sump pits in your basement for the water to collect in, or by installing one or more dewatering wells on the outside of your home.

I would assume will be far simpler to do these two things, than to dig around the entire exterior of your homes foundation.

Go three feet deeper than your basement floor, surround your casing with rock or gravel, insert pump on a float switch. Plug in.

Old Dog · Aug 13, 2007

excavating question

jimbo said:
I am not a builder...but I have this question: Is there an issue with excavating that deep on the outside of the foundation wall? In other words, is the fill supporting the wall, to where bowing or something could occur? Just asking. We don't have basements or foundation walls like that....everything is on a slab!

The fill isn't supporting the wall as you are thinking it might.One of the reasons you backfill a wall is to be able to slope away from the building for water drainage.Without it water can erode the ground around your foundation weakening it causing cracks and other unpleasant problems.It also is for leveling the ground around a building for landscaping/walkway purposes...
The issue that was being discussed was a safety issue.A 6 foot trench not properly shored up can collapse in on you burying workers/yourself.Not a pleasant way to go,being buried alive.

I'm not sure how old this house is but normally you waterproof the foundation before you backfill the walls to keep water out.The correct membrane
thickness is the key to success and using a fibre board to protect the membrane from damage during backfilling is important.
Other poster have him on the right track with drain pipe,sloping,ect...

He may still see dampness in his basement even doing all of this if walls are not waterproofed.
Hope I answered your questions...

Old Dog · Aug 13, 2007

Mini Niagra Falls!

molo said:
LOOK AT THE BOTTOM OF THE WALL< THERE IS A FAUCET COMEING OUT THE CONCRETE BLOCK THAT I DRILLED A HOLE IN THIS MORNING> I DRILLED A `1/4" INCH HOLE IN A FEW BLOCKS THAT WERE WET AND LOOK WHAT HAPPENED

I don't envy the problem that your having! Definitely need to get that water away from the house.Don't let anyone try to talk you into sealing the inside of the basement wall either.The goal is to keep the water out of the wall,not let in partway and stop it.
I left a post earlier here about your problem with another poster...I presume the foundation walls haven't been waterproofed or if they were the membrane has failed.
Trenching the walls and waterproofing would be how I would do it,along with drain pipes,possibly yard drains,gutter downspouts all connected to drain away from the house along with the ground sloped min.6-8 feet away.
Just have to make sure the water isn't going to be a problem for a neighbor down the hill from you...(legal issues can be a drag!)
The 6 foot wall,I'd hire a reputable co. to trench that for you.The membrane you can apply yourself,correct thickness is key,along with protecting the membrane when you backfill.
You could probably do what other posters have said,alot of good advice has been given...IMHO,only way to get the dampness out is with properly waterproofed walls...

Toolaholic · Aug 13, 2007

We do drainage work a lot.

FIRST off_ What a pig pen! There's too much to discuss Here!
Suggest You go to cont. talk forum. click on excavating forum. ,We have many posts on this. We work under Geo. Techs. plans on a lot of this. If You're in the bay area I'll stop by to guide. Also have backhoe and dump truck. Good luck

Molo · Aug 19, 2007

jadnashua said:
Two cardinal rules about surface water, drainage around foundations: You need the ground around the building to be graded away from the foundation, 6' is sort of the desired minimum, and control significant runoff towards it. That can be done with swales, ditches, or other landscaping features. The simple expedient of running the gutters out away from the foundation, and preventing surface runoff from running to the foundation should alleviate a lot if not all of your problem.

I am curious about what the slope graded away from the building does. I know it helps, but I do wonder about the direction water takes when it does start to saturate the ground... does it go straight down or does it spread out as it goes? If it spreads, it could work it's way over to the foundation, even with proper slope. Also, I, sure the surface affects drainage as well. For example, one side of the house has asphalt driveway right up to the concrete block foundation, yet parts of it slope toward the foundation! The other side of the house has 6" of soil with clay underneath. There is a slope problem here, and although there is clay, the moisture st ill goes down. I guess moisture can work it's way through clay? IF I COULD Resolve this prob without excavation that would be great. I'm just wondering if slope combined with proper gutters will do it?

TIA,
molo

Jadnashua · Aug 19, 2007

The driveway is a problem, it's probably at least 8' wide, so all of that water just flows towards the house in a rain or snow situation...constantly saturating the soil right by the house. Sloping the soil towards the house all around does similar things. Duming all of the water from the gutters right next to the foundation without a slope or some way to cause it to flow away from the house is like just sitting there and running a hose right next to the foundation.

Not saying that correcting these things will stop it, but it will help. The house where I grew up in has a bad ground water problem (the town's spring fed water supply is about 1/4-mile away), and without power and a good sump and pump, the basement would be a swimming pool for most of the year.

Frenchie · Aug 19, 2007

After re-reading this whole thread, I think your problem is 90% likely going to be solved by just sloping the yard & driveway properly. Aside from the driveway (which already, I'd be surprised if you didn't have problems), clay is notorious for poor drainage (hence runoff). Finally, I presume you have lawn all around? For surface runoff, lawns are 2nd only to pavement. And you're on a hill?

From the sounds of it, you're going to have to move a lot of dirt; might be worth it to rent a bobcat. But if you can get a 10% slope away from the house out to 6-10 feet away, you'll almost certainly be dry.

I've seen plenty of old, membrane-less basements that were dry, but they all had the right slope away from the house.

Molo · Aug 20, 2007

Thanks for the help. The asphalt goes right up to the building on one side. The other 3 sides is lawn. The house is a rectangle and the top side of the house (narrow end is into the hill) One long side is asphalt, one long side is lawn. The long side of lawn has slope problems, the asphalt has slope problems.
I am wondering about how to repair the asphalt grade. I have a place where i could buy it hot, is this what I should do?

TIA,
Molo

Jadnashua · Aug 20, 2007

On the uphill side, I'd consider a swale above the house ( a mini-berm - doesn't have to be high) that would direct any runoff from the uphill around the house.

Get a long, straight something and a good level and see what the driveway is doing on that side of the house. Maybe, if you have or can borrow one, a laser level. Find out how much it slopes towards the house. Then, you'll have a better idea of what may be needed. Maybe build a small curb, maybe have it regraded. Consider, a large, flat area that channels water towards the house...can't be good.

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