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please tell me the best way to waterproof my crawlspace

please tell me the best way to waterproof my crawlspace

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  #41  
Old 10-07-10, 05:37 AM
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Originally Posted by Perry525 View Post

The temperature in your crawl space stays about 12f, the water is the same as the ground.
i did have a thermometer in the crawl for the past year, actually not far from a drafty window down there...even with that draft, the space really never got below 50F and of course the RH was 90+ most of the time.
 
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  #42  
Old 10-07-10, 10:27 AM
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Relationship between 50F temperature, 90% humidity and condensation in your craw

Dew Point Calculation Chart (Fahrenheit)
%RH AMBIENT AIR TEMPERATURE IN FAHRENHEIT
20 30 40 50 60(70)80 90 100 110 120
90 18 28 37 47 57 67 77 87 97 107 117
85 17 26 36 45 55 65 75 84 95 104 113
80 16 25 34 44 54 63 73 82 93 102 110
75 15 24 33 42 52 62 71 80 91 100 108
70 13 22 31 40 50 60 68 78 88 96 105
65 12 20 29 38 47(57)66 76 85 93 103
60 11 19 27 36 45 55 64 73 83 92 101
55 9 17 25 34 43 53 61 70 80 89 98
50 6 15 23 31 40 50 59 67 77 86 94
45 4 13 21 29 37 47 56 64 73 82 91
40 1 11 18 26 35 43 52 61 69 78 87
35 -2 8 16 23 31 40 48 57 65 74 83
30 -6 4 13 20 28 36 44 52 61 69 77
At Sea Level (14.696 psiA)

I am glad you mentioned both your crawl space temperature and humidity.

You can see from the above chart that at 50F and 90% relative humidity the wood in your crawl space has to drop below 31F that is, below freezing, for ice/condensation to form on the wood in your crawl space.

This proves that the condensation on your wood only forms when the air entering your crawl space is warmer than 50F probably over 60F.

As the water in your crawl space is at the same temperature as the ground this shows that it is not the water that is causing the problem!

The problem is caused by the warm wet air that enters the crawl space through the holes, not the water!
 
  #43  
Old 10-07-10, 10:59 AM
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One teaspoon of water in 35 cubic feet of air

On the 10th July 2009 I wrote a blog to you saying:

Once you get below 90% humidity and 50f the amount of water vapour in the air is very low, below 5 grams per cubic metre.

And of course humidity is rarely as high as 90% at 50f.
--------------------------------------------------------------------------------Today I am adding:-

At this level 50F and 90% humidity the amount of water in the air is so low, it is almost dry.

A cubic metre of air equals 1000 x 1000 x 1000 cubic centimeters that equals 10,000,000 cubic centimeters
so only 5 grams/centimeters in 10,000,000 cubic centimeters of water.

To make that simple: One teaspoon of water in 35.31466 cubic feet
 
  #44  
Old 10-07-10, 12:23 PM
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i should have clarified that in the winter it really never got below 50, of course it was warmer in summer.

and regardless of the RH problem and how much we beat it to death, it's bad having water in the crawl..period. how am i supposed to crawl around in there to work on the electric covered in water? i'm pretty sure thats a bad idea. Also it's disgusting an your clothes get you soaked to the bone.

plus i'm a firm believer that ponding water harbors disease. My state has even put out bulletins that you shouldnt have tires outside gathering water and that we shouldnt let water gather in any place for any lengthy period of time. so if my state tells me it's bad for me, i have to believe them because they are never wrong

also, water is destructive and thats a fact. water continually running through my foundation will eventually cause damage. i have proof of that damage with cracks getting larger and larger. also while i havent checked my phone lines in a while under there, i did take one jack apart recently when i had DSL issues and the leads were corroded bad. no doubt because of water issues.

and finally, i spent 12K to have this waterproofed so i want it done right! unless he gives me a refund of course. then i can use the 12K to run the santa fe 24/7 for over a decade with that amount of money, even with our 30% higher rates next year lol
 
  #45  
Old 10-08-10, 02:50 AM
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Getting rid of water in crawl space.

You very kindly showed us pictures of the water inside your crawl space.
It is perfectly clear that the water is there because the floor was laid with a dip, the water collects in the dip and cannot run away.
In my blog number 35 I wrote:

And/Or you can add concrete to the floor of the crawl space, filling the dip and sloping from back to front to force the water to run away, under the front of your home.

What's wrong with that?
 
  #46  
Old 10-08-10, 04:50 AM
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wrong = spending 12000 for a drainage system that doesnt work. it simply must be fixed.
 
  #47  
Old 10-09-10, 06:56 AM
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Lets go over the ground again.

Way back you were asking how you could stop the water from entering your crawl space.

I advised that the water was coming down the slope and being trapped by your home.
I recommended that "you" should dig down and make a French drain, taking it round the end of your home, keeping the bottom of the drain level, until it came out of the ground at a point where the bottom of the drain and the ground surface were level. Advising that the water would then take the easy route and run out in front of your home.

I wrote that the ground water was making the wall of your crawl space damp and to avoid this, the French drain should be at least 4 feet deep, as that is the height that water rises within concrete, or preferably down to the bottom of the wall.

You replied that you could not take the French drain down the side of your home because of the breeze way.

You now write, that the people you hired didn't do the job properly and water is still coming in through the crack in your wall.

Exactly what had you asked them to do?
How did they propose to get rid of the water, without taking the French drain down the side of your home?
Did they build a sump to collect the water and install a powerful pump to eject the water into your drain?
What did they contract to do? What did they not do properly?

I wrote last year that standing water under your home does not do any harm and that there are many places in the world where homes are built in water, the latest to see is the new athletes village built in Bombay, India for the British 2010 Commonwealth games. As you can see from the pictures the athletes accomodation has been built in the middle of a river/open sewer. Presumably the only space left to build on?

If you must get rid of the water under your home, you need a change of tack.
 
  #48  
Old 10-12-10, 05:05 AM
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Originally Posted by Perry525 View Post

Exactly what had you asked them to do?
i asked him to stop water from getting into my crawlspace. since he was paid 12k it was up to him to decide what to do, i'm sure not the expert. here are some pics of his work after he dug it up. he admitted his team messed up now he's coming back to fix it. Thats what should be done. it's up to him to figure out how to fix it.

http://forum.doityourself.com/baseme...ml#post1770896
 
  #49  
Old 10-12-10, 05:33 AM
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IF your drainage pipes are correctly sloped correctly ( 1":10' ), freezing discharge water won't be an issue,,, running a 150w light on the sump during freezing temps keeps the discharge water from freezing,,, mold isn't difficult - 1c clorox:1gal water & a pump can,,, current code calls for NO foundation vents but i still like 'em - just know when to open & close them - open in warm weather & closed during the winter.
 
  #50  
Old 10-12-10, 08:35 AM
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Originally Posted by stadry1 View Post
IF your drainage pipes are correctly sloped correctly ( 1":10' ), freezing discharge water won't be an issue,,, running a 150w light on the sump during freezing temps keeps the discharge water from freezing,,, mold isn't difficult - 1c clorox:1gal water & a pump can,,, current code calls for NO foundation vents but i still like 'em - just know when to open & close them - open in warm weather & closed during the winter.
there is no sump, this is all gravity.

funny thing is, the manager of the excavating company told me his guys installed the footer drain wrong. Very roughly estimated, it starts with being 6+ inches above the bottom of the ditch at the farthest point away from the pipe outlets (those are the pics i linked to), then by the the time it gets allll the way to the front of the house, it's probably sitting on the bottom of the trench. He stated it should be a lot closer to the bottom of the trench so that water doesnt have to rise up 'so high' before it starts draining. It's a logical statement now that i heard him said it, just wish his guys would have known that. But i'm still betting there's a membrane tear and/or a yard drain cracked based on the behavior of water ive seen


edit: i've been trying to do more research and this site below appears to confirm that the drains can be installed pitched slightly or laid level. I'm doubting being up over 6 inches high qualifies for 'slight'

Foundation Drainage
The best location for rigid drain tile is alongside the footing. Minimum requirements for stone cover depend on whether the tile is flush with the top of the footing (top) or the bottom (middle). In either case, the top of the interior slab should be at least 6 inches above the top of the drain tile. The pipe can be laid level or pitched slightly.

my guess is that the water from the lower section of the pipe somehow interferes with the higher section and some battle ensues..but i'm not a hydrologist i dont know if the lower water can effectively push up or just block any water from the higher pipe. makes for interesting an study though.
 

Last edited by luckydriver; 10-12-10 at 08:50 AM.
  #51  
Old 10-14-10, 08:19 AM
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A real French drain!

The French drain was invented over 2000 years ago by the Romans, there are still working drains that are over 2000 years old in Europe.

A French drain is a trench or ditch that is filled with small stones to provide a guaranteed drain. As long as the bottom on the drain comes out level with the ground surface lower down a hill, the water collected by the drain will flow along the drain, water always takes the easy route.

The good thing about a French drain is that it cannot be damaged by freezing, the gravel/stones merely thaw out and back to normal.

Where the bottom of a French drain remains below the surface, then the installer must create a sump to collect the water and provide a pump with a float operated switch to move the water to a sewage pipe.

You do not need to worry about a French drain filling with soil and blocking up, as water moving through the ground is clean.

Although it is a good idea to add paving stones to the top, to stop running surface water that is carrying mud and stones from entering the drain.

You can understand my surprise when I saw your pictures, they look a total mess, not what most people expect a French drain to look like.

When finished the typical French drain looks like a gravel path.

What are those plastic pipes supposed to do?
They are not field drain pipes, field drain pipes have holes down each side, to let the water in.

How did the installers manage to get round your breeze way and garage?
 
  #52  
Old 10-14-10, 11:07 AM
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nothing was dug around the breezeway and garage because there is no crawlspace under them. also would have been a lot more work $$$$. Actually there was a yard drain put in back of my breezeway because it always flooded. Now it does not. it's 100% dry in any storm. So that definitely fixed that. i'm so glad i can now leave down my carpet and stuff.

the basic description of the existing system is this:

entire house excavated to footer level. I'd guess 2-3ft out from house. Black tar put on the wall and then a membrane laid down against the house and the bottom of the trench, basically an "L" shape. Then they put a few inches of gravel on top of the membrane and then

1. they put in one pipe with holes at 4 and 8 oclock so that when the trench fills up the water gets carried away. however his guys put this pipe up too high towards the back of my house , i guess they figured it needed slope, but the manager told me no, that 'footer drain' should be much lower to the ground, not 6+ inches high in the ditch. so he needs to lower all that pipe

2. a second pipe is used to collect all downspout water from the entire house.

3. a 3rd pipe is used to collect water from 3 yard drains in back of the house. ( he may even add a 4th right where it's leaking in my crawlspace as i have a huge back yard which 'empties' down onto the back of my house. it's a water nightmare)

then he filled the trench with tons of stone and a few inches of topsoil and then grass.

all 3 pipes lead around my entire house (except no yard drains needed in the front so just is footer and gutter pipes) and then slope down a nice embankment and empty out at least 30 ft away from the house.

from all i've been reading and what people tell me, this footer drain being so high off the bottom of the trench is the real culprit here. no one has said that the drain should be sloped so many inches above the bottom. I guess once it's on the bottom of this trench, all the water will get carried away

----------------------

i have another issue i'm separately addressing as the one gutter is overflowing and pouring down the side of the house and behind the membrane. that 'should' be easy for me to fix myself.
 
  #53  
Old 10-15-10, 02:09 AM
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French drain pinch point causing back up of water and water damage.

I would suggest that the possible problem is nothing to do with the field drain pipe.

In the normal way a French drain has an enormous capacity, laid across a field it is wide and deep and can contain a vast amount of water.

In your case, you have a pinch point, the exit pipe is overloaded and cannot cope with the amount of water trying to get away, the water is backing up rising up the wall between the plastic sheet and the wall.
The choices are, lower and widen the French drain to cope with the amount of water, (difficult to judge) a lot of hard work, or get rid of the exit pipe and extend the French drain down the front garden. Or add another exit pipe.

I suggest you measure the internal diameter of the exit pipe and ascertain its capacity, then measure and add together the various supply pipes to see if they amount to a greater volume.

The extension of the French drain down the front is the best option as you can be sure it will cope with the water load and it will not be damaged by freezing.
 
  #54  
Old 10-15-10, 05:19 AM
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it's 4 inch pvc all pipes. how does one ascertain capacity vs actual rain need to be taken away? he told me after he installed it he came by during a storm and all 3 pipes were 3/4 full blasting out. but i actually have never gone down during a storm to watch the water come out.

and i dont understand how the water could back up between the rubber membrane and the wall. it literally would have to travel 1-2 feet away from the house first, go down around /under the membrane at back towards the house at least 3 feet. My belief, though i have no proof, is that water generally travels down, not left then right a total of 4-5 feet. but perhaps the membrane is ripped at the angle of the membrane and that definitely would explain it.

even if your explanation is correct and it's backing up, why would it only be leaking at the point farthest away from the exit and not at the run closer to the exit where i assume the volume is always running at capacity?

Ill try to post an overhead pic of the house later so you can get a feel for the layout

edit, unfortunately i cant get into my photobucket account so will have to upload over the weekend
 

Last edited by luckydriver; 10-15-10 at 05:50 AM.
  #55  
Old 10-16-10, 05:28 AM
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Heavy rain = French drain overflows?

The amount of water that can flow through a 4 inch pipe, is controlled by its length, how smooth the inside of the pipe is and the height of the water above the pipe exit.

The amount of water the pipe is required to handle is ascertained by measuring the size of the yard in square feet and the amount of rain landing in a given time usually an hour.

Once you measure your yard and work out the amount of water that can land there in a given time you have a starting point, because there will be other water that is landing higher up the hill and coming down through the ground.

Think of running a bath with an open drain.
At first with the water running slowly, it all goes down the drain as you increase the flow, the bath gradually fills, the water runs away faster as the water rises and the pressure rises.

This happens with your yard and French drain
the harder it rains the more water is trying to get away down that 4 inch pipe, the higher the water rises inside the French drain, and makes its way into your crawl space.

If you have really hard rain, for some time, the French drain may overflow.

Showing that they should have opened up the cracks in your wall and filled them with cement or fiberglass resin to stop ingress.
 
  #56  
Old 10-16-10, 05:18 PM
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well maybe an additional yard drain isnt a bad idea. it's up to him. he's the pro. and i'm going to insist nothing be backfilled until we are sure the water doesnt leak into the crawl.

here are some links to pics of the yard/house with notes, they are too large to have posted directly here

http://i371.photobucket.com/albums/o...e_drainage.jpg

http://i371.photobucket.com/albums/o...view_house.jpg

http://i371.photobucket.com/albums/o...view_house.jpg
 
  #57  
Old 10-22-10, 03:54 AM
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Too much rain!

Had a look at your layout.
And noted your comment about six inches of rain.

After you have measured your yard and ascertained the square footage then divided by two to get the number of cubic feet of water that falls on your yard.
Measure the existing French drain and ascertain its volume in cubic feet then divide by three to ascertain the approximate amount of water it can hold.

Then measure the lowest point of the crack that is letting the water into your crawl space, and using that point as your marker ascertain how deep the water can be before it runs into your crawl space.
And divide that by three to ascertain the amount of water in cubic feet that can be held in the French drain before it runs into your crawl space.

Then you will know the overall net rainfall on your yard.
The amount of water that could be held in your French drain.
The amount of water that can be held in the French drain before it runs through into your crawl space.

You will almost certainly know that the installers of the French drain did not make it big enough to cope with the amount of rain you have from time to time. Are they local?

The check on the net or with your local library or local weather station to find out the largest amount of rain that has been recorded in your location, this will give you a useful guide.

The cracks need to be filled and made water tight.
The French drain should be completed correctly at both ends to maximise the amount of water that can be shifted in the shortest time.
Then you need to build a secret wall in a "V" shape across your yard, with an open ditch or dip above it angled at 20 degrees or more to collect the excess water and divert it to the sides away from your home and to keep it (the ditch) in a normally dry condition.
The secret wall needs to enclose an area that will receive less rain than the French drain can cope with, to ensure the French drain does not overflow.
 
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