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Ken
MVM
join:2003-06-16
Markle, IN

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Ken

MVM

How to fix water problems in your crawlspace

I recently had to deal with a big water problem in a crawlspace, and thought it was interesting enough to post about. My Mom owns and lives in half a duplex here in Central Indiana. A duplex here by the way means two single family homes next to each other sharing a common wall, I only say that because I know the term duplex means other things in different regions. When she first moved in 7 years ago, I noted the crawlspace was wet, and needed new plastic put down. Unfortunately things sometimes get put off longer than they should, but recently I had the chance to finally fix the problem.

First off let’s talk about why the crawlspace is wet to begin with. My Mom’s house has some serious grading issues around it causing water to run back into the house. Usually when an excavator digs out a crawlspace or basement they perform 3 steps. Step #1 is do dig out the hole, and haul away most of the spoils. However they do stack some of the spoils around the hole to use as backfill after the foundation is done. Step #2 they come back after the foundation and sometimes the first floor deck is down and backfill against the foundation. They also do a rough grade to slope the dirt basically where they want it. As several weeks go by and it rains, the dirt up against the house will settle and leave a low spot. This is why the excavator will come back for the all important step #3 which is to perform a final grade after the ground has had a chance to settle. On my Mom’s house they either skipped step #3 or performed it before the ground settled. The end result is there is a low spot all around the perimeter of my Mom’s house. Just outside of this low spot is a slight mound of soil about 4” high and 10 feet wide that is shaped like a large crescent moon.



Above is a super generic map I made in Paint to illustrate the mound, and the location of the downspouts.

As you can see any water coming from the two downspouts gets stuck and can’t go anywhere. The water has no choice but to sit up against the foundation and slowly find its way down into the soil, and eventually into the crawlspace. Ideally I would like to rip up my Mom’s yard and regrade it to fix the problem from the outside. However trying to convince someone to let you destroy their entire yard and planting beds can be difficult. I believe that later this year or next year I will have her convinced to do just that, but in the mean time I wanted to fix the problem from the inside. Fixing the problem from the inside now, and then from the outside later is an ideal solution because it gives you some redundancy to the fix. It’s a kind of belt and suspenders approach. For now however let’s just concentrate on fixing from the inside only.

Here is a picture of what the front of the house looks like after 30 minutes of rain.

Picture taken from the front door, facing the downspout

You can clearly see all the standing water which has no place to go, and if you look just past the left of the bush you can see the slight mound. All the water coming out of that downspout just runs back against the house.

Below is what it looks like inside the crawlspace after that same 30 minute rain. Water is spraying out from holes in the mortar joints.

Picture taken along back wall of house


Below are five more pictures of what the crawlspace looks like after a rain. The water continues to stand for several days before it recedes.


Next to sump pit looking towards garage


Next to sump pit looking towards back door


Next to sump pit looking towards top right corner of house


In the middle of right wall looking towards top right corner of house


All the way up looking into top right corner of house


What is more amazing is the crawlspace does already have a sump pit with a pump in the bottom right corner of the house. The problem is the ground is so uneven that low spots exist where water must build up 5" deep before it is high enough to run up and over to the sump pit. The second picture in the series above in fact is almost showing the sump pit, it is just to the left of the big pile of dirt. That big pile as you can see is holding back a huge ocean of water from getting to the pit.

The answer to this problem is simple; we need to dig a trench around the perimeter of the house leading back to the sump pit. If you refer back to the top of this post and look at the map you will see this trench line marked. It’s very important the trench slopes downhill the entire way to the sump pit, so water will flow freely. Next you put in some slotted pipe with a sock around it, and fill the trench with pea gravel. Then when water comes in from the block wall it will hit the gravel and drop down into the pipe, and then it will flow around to the sump pit. Sounds pretty simple, but it is horrible back breaking work. It is very humid, very muddy, you are bent over the entire time, and using a little shovel. When people get an estimate from a company and they wonder why the estimate is $5,000 this is why, its horrible work. I can easily say that in my 15 years in and around the construction industry this was the hardest and worst job I have ever done. I did it only because it was for my Mom, I would never do this again for anyone else. If any of you reading this are thinking about doing this yourself, let me warn you, it is not easy. My Moms crawlspace was so wet and muddy that I had to go to Dick’s Sporting Goods and buy a set of rubber waders that fisherman use.

I spent every day for 2 and a half weeks digging this trench. I know it doesn’t look like much, but this was very dense hard clay, and it takes a lot of effort to dig in it. Especially when you don’t have a full size shovel you can put your foot on to drive into the ground. In a crawlspace you have to use a small shovel, and you have to rely on your upper body strength alone to drive the shovel in the ground. In short, it’s a workout. Here are the pictures of the trench. Notice near the sump pit the trench starts out about 14” deep, and near the front door, it’s only about 3” deep. In effect I really have two separate trenches one leaving the pit on the left and one leaving on the right; they both travel uphill around the house until the meet each other near the front door.


Next to sump pit looking towards the back door


In the middle of right wall looking towards top right corner of house


Water flowing into the pit after a moderate rain


Similar to 3 pictures above, looking towards back door


At this point in the project the trench is done, and water is flowing nicely into the sump pit and being pumped away. Why do we have to continue on? Well slowly over time the trench will collapse in on itself, so it’s important to fill it with something. In a situation where you don’t have much water movement, using just gravel in the trench to create a French drain would be adequate. However if you want to move a lot of water, the gravel is to slow, and a pipe is called for. Based on how much water I saw flowing through the trench, I opted to go with 4” corrugated slotted pipe, with a sock. I used 120’ at a total cost of about $70 in pipe. I then bought a total of 50, 50 pound bags of pea gravel at a total cost of about $110. Buying pea gravel in a dump truck would be cheaper, but there is no easy way to move around loose pea gravel. Buying it in 50 pound bags, while more expensive, makes it much easier to move around. The next 7 pictures show the pipe, pea gravel, and sump pit.


Pipe in the trench, right wall looking towards top right corner of house


Pipe dumping water into sump pit, It hasn’t rained in 2 days


Just half of the pea gravel stack, other half is behind me


Pipe with pea gravel over it


Finished pea gravel, right wall looking towards top right corner of house


Finished sump pit area, looking towards back door


Closeup of finished sump pit


The last step to this project is to put a new layer of plastic down. Why do we need plastic? Even though the water is going to run into the pit and be pumped away, the ground is still going to remain quite moist. This moisture is going to slowly enter the air, and make the air very humid. This humidity promotes wood rot, fungus growth, and damaging insects like carpenter ants or termites. In short, humidity is very bad. Putting down a layer of plastic stops the moisture from entering the air. One mistake people sometimes make is to run the plastic over to the block wall and stop it there. The problem is if water comes spraying in from the block, it will end up on top the plastic. Water on top the plastic won’t be able to enter the trench, and it will take a very long time to evaporate. What you want to do is run your plastic up the wall, ideally to the level of the dirt outside. This crawlspace has 2” rigid foam insulation on exterior walls, so I brought the plastic up about 6” from the bottom of the floor joists, which is about where the outside dirt level is. I used tyvek tape to seal the plastic joints together, and seal it to the insulation. I also took the time to wrap the block columns in the middle of the crawlspace with plastic. This again is another important step at combating humidity. Any masonry surface has the ability to draw water up out of the ground, and give off the moisture into the air. So wrapping the columns with plastic helps keep the humidity down. In short, if it’s masonry, cover it with plastic. These next 5 pictures show off all the plastic work. Take note of how carefully I taped every seam, this is all to help stop water vapor from the ground getting access to the air.


Up in the front of the house, looking towards the front door


Closeup, top right corner of house


Closeup of wall, plastic to insulation taping


Near sump pit, looking towards top right corner of house


Closeup of column wrap


The project is now done, and I’m happing to say that all the water problems are gone, along with the high humidity in the crawlspace. I still hope to regrade the yard from the outside, and if that does happen then this thread will have a Part 2. Total cost of this project was about $250 in materials, and about 50 man hours of labor. So in the end you can pay $5,000 to hire someone to do it, vs $250 to do it yourself. I don’t want to talk anyone out of doing something themselves, but don’t be mesmerized by just those numbers. It took me a full month, 8 hours a day, 5 days a week, to put in 50 actual work hours. The conditions are so bad you can’t actually work for 8 hours a day. I averaged about half an hour work, before I had to get out of the crawlspace and rest for at least an hour. So in a typical day, I was only getting about 2 actual work hours done. So in total I spent 8 hours a day * 5 days a week * 5 weeks = 200 hours at my Mom’s house, and yet was only in the crawlspace working for 50 actual hours. It is the most grueling and exhausting work I have ever performed, and is certainly not for the faint of heart.

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO

nunya

MVM

Bleh. Nothing I hate more than a "crawl" space. They are vile areas. My theory is either slab it or put a basement in.

Glad you got it fixed.

clevere1
Premium Member
join:2002-01-06
Vancouver, WA

clevere1 to Ken

Premium Member

to Ken
Nice.

jjoshua
Premium Member
join:2001-06-01
Scotch Plains, NJ

1 edit

jjoshua to Ken

Premium Member

to Ken
That's a lot of work. You might have rented a jackhammer to help break up the dirt.

You could have also tried the same thing on the outside of the house. Normally a French drain is installed to move water that comes up from under the foundation and slab, not water that comes through the walls.

Why did you dig the trench so far from the foundation? Also, what did you do with the dirt from the trench?

Ken
MVM
join:2003-06-16
Markle, IN

Ken

MVM

I don't think I would have wanted to lug a jackhammer around down there.

The trench is out from the wall because of the footer. In most places of the crawlspace the footer extends in about 12", so I came in about 18". You can see a couple shots along the right wall where there is a pillar against the wall, I had to come in even farther there to get around it's footer. Ideally it would have been nice to take all the dirt out of the crawlspace, but that would have been just way to much work. So I just threw the dirt towards the middle of the house and leveled it out. It ended up raising the level in the center of the house about 4".

mattmag

join:2000-04-09
NW Illinois

mattmag to Ken

to Ken


Looks like you did a very nice job. I would speculate that you carry that level of detail in your work over to your customer work as well, so you are likely to have many happy customers!

natedj
Elected
Premium Member
join:2001-06-06
Irmo, SC

1 edit

natedj to Ken

Premium Member

to Ken
As soon as I saw the first picture of the crawlspace and noticed the the CMU block was stacked 3 units high (24") I said to myself that job is going rank in the top five of being the most pain in the butt to do. Jobs like these are not just priced by materials and labour, but by the mental and physical anguish that goes along with it. Accomplishing this feat is as close as you're going to get to digging a tunnel out of a prison with a spoon
You did a great job and I know lugging around (50) 50# bags of gravel was no picnic either. I'm surprised that the condition of the floor joist looked as good as it did with this sever water problem. Does your mom own the place or does she rent/lease?
Thanks for taking the time to take pictures and document your steps. I learn a thing or two about the vapour barrier.
Awesome work !

AVD
Respice, Adspice, Prospice
Premium Member
join:2003-02-06
Onion, NJ

AVD to Ken

Premium Member

to Ken
said by Ken:

The trench is out from the wall because of the footer. In most places of the crawlspace the footer extends in about 12", so I came in about 18".
smart

rfhar
The World Sport, Played In Every Country
Premium Member
join:2001-03-26
Buicktown,Mi

rfhar to Ken

Premium Member

to Ken
There is obviously a lot of love in that job.
I put a four inch corrugated tile on a couple of my downspouts and run it away from the house to a drain like your put in the basement and then tied the cover on with a couple wire ties. It works good for me.

dennismurphy
Put me on hold? I'll put YOU on hold
Premium Member
join:2002-11-19
Parsippany, NJ

dennismurphy to Ken

Premium Member

to Ken
said by Ken:

The project is now done, and I’m happing to say that all the water problems are gone, along with the high humidity in the crawlspace. I still hope to regrade the yard from the outside, and if that does happen then this thread will have a Part 2. Total cost of this project was about $250 in materials, and about 50 man hours of labor. So in the end you can pay $5,000 to hire someone to do it, vs $250 to do it yourself. I don’t want to talk anyone out of doing something themselves, but don’t be mesmerized by just those numbers. It took me a full month, 8 hours a day, 5 days a week, to put in 50 actual work hours. The conditions are so bad you can’t actually work for 8 hours a day. I averaged about half an hour work, before I had to get out of the crawlspace and rest for at least an hour. So in a typical day, I was only getting about 2 actual work hours done. So in total I spent 8 hours a day * 5 days a week * 5 weeks = 200 hours at my Mom’s house, and yet was only in the crawlspace working for 50 actual hours. It is the most grueling and exhausting work I have ever performed, and is certainly not for the faint of heart.
So, if I'm doing the math, and we subtract out the material cost, the $5,000 job would be $23.75/hour.

Yup, I'd pay someone $5k to do it instead. My time (very thankfully) is worth more than $23.75/hour.

Ken
MVM
join:2003-06-16
Markle, IN

1 edit

Ken to natedj

MVM

to natedj
said by natedj:

I'm surprised that the condition of the floor joist looked as good as it did with this sever water problem. Does your mom own the place or does she rent/lease?
She owns just her half, the neighbor owns their half. I was also surprised all of the floor joists were in good shape, I was expecting to see mold everywhere. I guess we got lucky since we put it off for so long.

KrK
Heavy Artillery For The Little Guy
Premium Member
join:2000-01-17
Tulsa, OK
Netgear WNDR3700v2
Zoom 5341J

KrK to Ken

Premium Member

to Ken
Not only an example of a pro job, well done, but also a great detailed post with great photos ..... Thanks very much for sharing.

I've only got one question to ask, it's about the sump pump itself... is it battery backed up? I could see a thunderstorm knocking out power and also causing torrential downpours--- if the pump doesn't run for awhile the water will backflood under your plastic and likely break apart your taped joints and ruin some of your hard work

I also agree with you the long term best solution is to do the regrading work outside the home, raise the dirt up a little around the foundation and remove the "berm" that prevents water from running away from the house. I see you have the "extenders" on the downspouts.... They could be longer OR you could have them run into french drains that take the the water out by the curb. (or etc.)

Anyway, great, GREAT post! TY TY
nocannothave
join:2006-10-14
Kennewick, WA

nocannothave

Member

said by KrK:

Not only an example of a pro job, well done, but also a great detailed post with great photos ..... Thanks very much for sharing.

I've only got one question to ask, it's about the sump pump itself... is it battery backed up? I could see a thunderstorm knocking out power and also causing torrential downpours--- if the pump doesn't run for awhile the water will backflood under your plastic and likely break apart your taped joints and ruin some of your hard work

I also agree with you the long term best solution is to do the regrading work outside the home, raise the dirt up a little around the foundation and remove the "berm" that prevents water from running away from the house. I see you have the "extenders" on the downspouts.... They could be longer OR you could have them run into french drains that take the the water out by the curb. (or etc.)

Anyway, great, GREAT post! TY TY
Agreed. Great post.

On This Old House I saw a sump pump powered by city water. Once the electrical power is disconnected and the secondary float (above the regular electrically powered float) is engaged, city water is piped into the sump pump, thus sucking out the sump's contents via vacuum pressure.

Search google for "water powered sump pump". Pretty damn cool device.

Ken
MVM
join:2003-06-16
Markle, IN

Ken to KrK

MVM

to KrK
The sump pump doesn't have any kind of backup, so yes if the power is out for more than 30 minutes the crawlspace will start to flood. Have a back would be nice, but I'm hoping we can get by without until I can regrade the yard.

Rxdoxx

join:2000-11-03
Middle River, MD

Rxdoxx to Ken

to Ken
Nice work!

It looks like a drainage trench would be useful outside the house, getting to the other side of the mound.
If nothing else, I'd consider temporarily getting those downspout ends emptying further out, even if I had to make it look ugly and raise them up a couple of feet to carry the water past the mound.

But man you sure put labor in, I'm sure your back sang to you every night.

supernac3
join:2003-03-26
Springfield, MO

supernac3 to Ken

Member

to Ken
Looks nice, I'm getting ready to put down a vapor barrier as well. What kind of tape did you use and where did you get it? I was thinking of using duct tape, but I'm worried it won’t hold in the long run.

Ken
MVM
join:2003-06-16
Markle, IN

1 edit

Ken

MVM

Generically it's referred to as housewrap tape, but the name brand I used is Tyvek tape. »www2.dupont.com/Tyvek_Co ··· ape.html. I bought mine at Lowe's.

It is very expensive at about $12 a roll, and the rolls aren't very big. The reason I like it is because it sticks to plastic pretty well, and isn't affected by moisture. I'm sure if you dunk it underwater it will loosen up, but just moisture alone won't loosen it up.
Hahausuck
Premium Member
join:2003-12-14

Hahausuck to Ken

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to Ken
Holy smokes Ken that is awesome.

I had a post here last winter about a crawlspace that was flooded about an inch or two across due to a water spigot being kicked open outside the house, and water running into the space through the vents. I researched flooded crawl spaces and came across a whole mess load of contractors that were offering exactly what you did, but no how-to guides. I can figure out how to do it easily enough but what you did is amazing. Hats off to you.

CylonRed
MVM
join:2000-07-06
Bloom County

CylonRed to Ken

MVM

to Ken
I need to hire you for my crawl space - it is not that bad but it needs help...
markopoleo
join:2003-04-02
Bonne Terre, MO

markopoleo to Ken

Member

to Ken
Pea gravel was prob not the best solution, it works..sorta. But it does attract algae/muck on it which would block water over time.

In my area we use half inch rock around footings and drains. Big enough for water to flow through, but small enough to keep muck out.

You can safely remove all that plastic to. Does not do anything but maybe keep you dry..unless of course that was its purpose. :P

Good job though!

Ken
MVM
join:2003-06-16
Markle, IN

Ken

MVM

That's what everyone here uses for footers, foundations, and everything else drainage is pea gravel. I also explained the purpose of the plastic, and it does a lot more than keep you dry. The plastic stops ground moisture from entering the air and making a humid environment in the crawlspace. High humidity promotes wood rot and insects. I can't imagine they don't use plastic in your area for the same purpose.

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO

nunya to Ken

MVM

to Ken
Your climate is relatively the same as mine. Very hot in the summer and very cold in the winter. So, I have to ask - Why aren't the floors and ducts insulated? I see the styro-board, but I wouldn't think that would be very effective.

Ken
MVM
join:2003-06-16
Markle, IN

Ken

MVM

Insulating the ductwork isn't required here, so literally nobody does it. I know sealing the ducts and insulating them would help the house cool better in the summer. However all that air leakage in the winter helps keep the crawlspace warm and the pipes from freezing. So maybe insulating them might cause frozen pipes? I personally would like to seal over the crawlspace vents and add a cold air return and a couple supplys down there to make it conditioned space.
TherapyChick
join:2003-09-19
Fayetteville, NC

TherapyChick to Ken

Member

to Ken
How big a deal was just putting the plastic down? I know you said the whole job was grueling and took like 50 hours or so.

I only need the plastic put down for about 1000 sq/ft, would you say that was really hard?

The people who told me that said they'd do it for about $580.

Looking back, what would you do in my situation?

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO

nunya

MVM

Smile and write them a check.

Ken
MVM
join:2003-06-16
Markle, IN

Ken to TherapyChick

MVM

to TherapyChick
The plastic is the easiest part of the job, but still requires a lot of climbing over and under things. It's also pretty hard on your knees. Should you do it yourself? It depends on how easy your crawlspace is to get around in. My mom's is about 30" from dirt to underside of joists, so it's not to bad to crawl around in. I have been in some where it's like 10" from dirt to joists, and those really suck to work in. How hard is yours to crawl around in, and are you in the shape to do it?

Make sure whoever does it that you use preferably an 8mil plastic. The 4mil stuff gets holes in it really easy from just crawling around on top of it, and while the 6mil will last a little longer it still rips easily. The professional waterproofing companies use a real thick reinforced plastic, but you definitely pay more for that.

dandeman
MVM
join:2001-12-05
Chapel Hill, NC

1 edit

dandeman

MVM

Be careful with the Dow Styrofoam (I noticed in the pics) to make sure it doesn't touch the ground anywhere...

I used leftover pieces of same to make a form to pour concrete around my well head and to provide some cold weather insulation so ground heat would keep the well head from freezing..

I have found that termites love to eat the stuff and will tunnel through it.. If it's in contact with your wood foundation and with the ground, termites will have a protected path to get into the wood. This is Dow Styrofoam purchased years ago.. I guess its possible newer vintage production might have an insecticide added to the composition.