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c2g 12-02-2010 02:12 PM

basement waterproofing question
I'm about to convert my basement to a living space. 100 yr old stone house, stone foundation in basement. Moved in a few years ago and we would get some water near the walls and corners after heavy rains. Then I removed the concrete driveway that ran along the house with plans of putting in a slate patio. The few months before I put the patio in, I would get streams of water running through the basement during rainstorms. I put the patio in with a good pitch away from the house this past summer (no french drain outside though), and now it's pretty much dry - maybe a tiny bit of dampness after a really big storm.

We want to run a daycare out of the basement so I want to take every precaution to do this right. Do I need to do all of the following?

1. have interior floor french drain system with sump pump put in.
2. patch larger wall holes with cement
3. brush clean and then coat walls with something like Ames Blue Max liquid rubber paint
4. frame with galvanized studs, insulate, and use green drywall.

Does this sound like a plan? Am I going overboard or missing anything? The "basement waterproofing companies" seem to tell me one thing and the general contractors say another, so really not sure. Thanks.

DIY_ing_Guy 12-03-2010 06:55 PM

I hope I can make this story clear. My house sits near the base of a 1-acre, 25-degree-slope, so the uphill-facing side gets a lot of rain runoff from the hillside and half of the roof. Very solid concrete poured walls and nice thick concrete floor. I had an occasional basement water intrusion, so I had one of the famous perimeter drains installed. I'm doubtful that I would recommend it to someone else, as I now understand some fundamental design problems.

First, I had mostly cured my occasional basement water intrusion by installing a French drain outside, doing some re-grading (not much was possible), and extending the gutter drains. Still had minor water rivulets during extreme weather, seemed to be coming from the floor/wall joint in one wall section. I am gutting the basement for a remodel, so I figured the perimeter drain was a guaranteed final step for a dry, mold-free basement before I rebuilt the walls.

Here's what I've (expensively) learned.

HOW IT WORKS: First, the perimeter drain is a plastic weeping tile-like channel set in a trough jack hammered into the concrete floor and the plastic channel is set into a 3/4"-crush gravel bed, all covered with hand-troweled concrete. Like a weeping tile, the plastic channel provides a runoff for the bulk of the water, but water can move in/out of the plastic channel from the surrounding ground and gravel bed. The walls are covered with a semi-rigid plastic that directs any thru-wall seepage down the concrete side of the plastic, and into a thin flange that extends up out of the concrete at the base of the wall, so the water goes into the plastic channel. The plastic channel feeds into a sump (mine used the same sump well & pump that my existing weeping tiles feed into).

1. The Wall Covering - This is great stuff. It's thin but strong, does not tear easily, and is easily patched with provided tape. I think part of my problem was a thin crack at a wall corner, and I think this layer will help.

2. Depth of the Plastic Channel - Because of the flange where the wall covering drains into the plastic drainage channel, the channel is set into the floor at a uniform and shallow depth. This causes several problems:

2.1 Slope: The theory is, once the ground and the gravel bed are saturated up to the plastic channel, any further water can run off the the sump. Good runoff requires 1/4" per foot slope; since my floor was pretty level, that slope does not exist. Instead of running off into the sump, some of the more distant parts of the system seem to collect a local "pool" in the gravel.

2.2 Depth of the channel and gravel: Since the plastic channel depth is limited by the floor drain flange, the channel and the gravel around it are only covered by and an inch or inch and a half of concrete. So if water pools in the gravel, it can soak into the concrete from below. My old floor had a 4", very hard, machine-troweled concrete barrier with plastic under it, so the only symptom was a trickle of water incursion at the edge. Now the water pool is soaking into 1-1.5" of less dense & less even-depth "patching" concrete. After the first big rain I had some surface dampness in a small area. (A rain this size would NOT have pushed water in the old floor).

The installer admitted the problem was theirs when they saw it; they said it happens "maybe 10-20% of the time." (Never said that at SALES time, though, did they?) They ran to Big Orange for a spray-on penetrating sealer and said it usually cures the problem. I've run a hose into the trough for a few hours (which is how I re-created the soak-thru to show the installer the first time), no sign of seeping now. Equally big storm this week, it's bone dry. I hope it's cured, but I feel a bit like I paid $100/ linear wall foot ($5K) for a $50 bottle of sealer. (Grumble.)

The installer has promised, in writing, to come back, dig it up, and fix it if it shows any dampness again. Two problems with this: 1) I suspect the only fix would be a second sump located right where the seepage showed, and I'll bet that's an expensive new feature (Grumble); and 2) until I am confident it's dry, I'm not excited about finishing framing & covering the walls. So much for my project schedule. (Grumble.)

2.3 - Framing: I posted another thread about this so I'll be terse. To avoid Ram-setting a nail into that plastic trough I have to frame out a few extra inches, and I'm still worried about penetrating that thin concrete & encouraging more seepage. Installer recommended construction adhesive to attach the sole plate, but I have not yet resolved whether that will pass inspection; code specifies a nailing frequency in my county.

In the end, at least the incursion is no longer enough to form running rivulets, even if the sealer does not work or last. But... (Grumble. Again.)

Sorry C2G for such a log-winded reply but I know a lot of people like me (and maybe you) are spending a lot of money on these systems. I'm not grousing about the cost or the installation, I liked the installer, and I think they are honest, but I think the system has some design flaws, despite it's national marketing and well-know TV home improvement dude's U-Tube endorsement. It has some good features and might be great solution for some situations. Hopefully this will help you and others make a more informed decision.


1910NE 12-03-2010 07:34 PM

the only cure for a damp basement is to fix the drainage outside, and even then....

Octopus 12-03-2010 09:11 PM

Yes. Interior footing drains. At perimeter and in the field. DO NOT slope the 4" perferated drain pipe. Perf pipe needs to be level throughout. As pipe exits basement then slope captured water through solid 4" drain. Holes down when installing interior footing drains. Water table is rising. You are not capturing water that is draining down through the soils, you are capturing a rising water table. Sleeve pipe with filter fabric. DO NOT use "crushed" or jagged rock. It packs tightly and water will not flow through it easily. Round stone is best and is a good base for a concrete slab. 1 1-2 minus washed rock is best.

Gnfanatic 12-03-2010 09:25 PM

oct. if you dont slope the 4 inch pipes then how does the water travel to the pump??? I will be doing this job soon to my own basement.


Octopus 12-03-2010 09:45 PM

A water table rises "level" into the holes that are facing down

The water will flow through the path of least resistance. Remember the pipe, for lack of a better, term is 4 inches high and you will, or should, have several runs of them. When the water reaches the top of the pipe then it wants to flow into and through the solid downward sloped pipe going to the sump

For instance, if you have a rectangular basement you will want to have drains at the permiter and then divide the the width into thirds or forths using 90 degree elbows and 4" tees

All the perf pipe is attached together to make up one continuous pipe in any given shape. Do not dead end any of the runs

Gnfanatic 12-03-2010 09:52 PM

wow, all this time i was thinking it was differently designed?? sheesh! I actually thought you doug out maybe 2 ft down around the perimeter of the basment, install some round stone, lay PVC pipe down with holes facing down (put a sock on it to) then the pipes will be sloped towards the pump hole. You are talking about something totally different that I have never seen,. I guess this is why some of them work and some of them dont?

ConcreteTreat 12-05-2010 03:26 PM

1. have interior floor french drain system with sump pump put in.

That sounds like a good idea. Try to get a French drain system that you can concrete over -- that way you don't have an open gap along the floors that will let in humidity and odors. Also, eliminating an open gap will protect your system from clogging with debris from the floor.

2. patch larger wall holes with cement
Instead of cement, try polyurethane. Your walls are going to flex and shrink with temperature, and a rigid patch may crack or cause new holes to form somewhere else. Polyurethane can expand and shrink along with your walls.

3. brush clean and then coat walls with something like Ames Blue Max liquid rubber paint

Never, never, never use rubber paints -- or any paint for that matter. Paints will flake and peel off your walls in as little as six months.

Check out what happened to the basement of the house I'm renting when they applied waterproof paint. Then applied it again, then again. Also- notice the ugly gap around the edge from the landlord's beautiful French drain system.

(these images are huge, so I'm going to link to them instead of displaying them)

As someone who works for a concrete sealer manufacturer, I'm biased and should probably refrain from recommending a specific sealer. If you want me to tell you, send me a private message and I'll let you know.

But don't use anything with laytex. Silate-based products are good. Get ones that penetrate into the concrete and have no natural organic material.

4. frame with galvanized studs, insulate, and use green drywall.

If you seal your walls and floors, you won't need the green drywall. It's much more expensive than regular drywall, and really, they both can grow mold and be destroyed in a flood.

OH! One more recommendation -- upgrade your washing machine hoses. It costs $20 to get good ones from a hardware store. If your washing machine hoses burst -- which DOES happen -- you can have 500 gallons of water per minute in your home. That'd ruin your finished basement in a jiffy.

stadry 12-06-2010 02:43 AM

just about everyone who installs sub-floor water management systems has their little twists,,, we figure even 1 of those needs some maintenance over the yrs,,, we install cleanouts & inspection ports in our systems,,, that ' gap ' along the wall often catches drips that run down the wall,,, installing a combo french drain/radon system would close them, of course, but would also incorporate a wall vapor barrier & ( my choice ) air exchanger.

hydraulic or patching mortar is a better choice im-n-s-h-fo as nothing's waterproof on the interior ( negative ) side,,, so what if it were ? water would still penetrate to the depth of the applied coating - you just can't actually ' SEE ' it !

ps - your private message thingie don't work :no:

bob22 12-06-2010 07:14 AM

"We want to run a daycare out of the basement"
Something to consider if there is only one way out of the basement now, you will have to provide another egress cut out for fire purposes?

stadry 12-06-2010 08:50 AM

waterproofing can ONLY be done from the exterior - any work inside is called ( rightly so ) water management.

your patio may help temporarily but its not waterproofing by any stretch of imagination OR definition eg ' tiny bit of dampness ',,, 1 thru 4 sounds good to me altho be certain you're not trapping wtr behind your 100yr old walls,,, in genl, genl contractors are clueless about dry basements in my experience,,, no difference in performance 'tween crushed & river rock but BIG difference in price.

its difficult to diagnose a problem: leaking walls, rising water table, OR false water table,,, however any properly designed system will mitigate all 3 conditions,,, 4" s & d pvc w/holes up, down, sideways vs 4" slotted/holed corrugated = all about the same & we've used all,,, caution against 'socked' pipes as it allows silt buildup nearer the pipe,,, we line our excavation w/filter cloth & gain much more 'filterability',,, we also install cleanouts & inspection ports for maintenance,,, whether or not you'll need a sump & pump depends on existing elevation, slope, & grade.

Gnfanatic 12-06-2010 09:10 AM

Alot of you guys have stated several times in the past about the proper way to attack a water issue is from the outside. I agree with you 100% BUT what happens when you are like me and have flat property and no damn city drain in the front road?? where does the water go?so if I dig 8 ft deep around the outside perimeter of the house and I need to have a drywell thats at least 9 ft deep so the water is gravity fed, but then the drywell well will probably be full of water by then due to the hgih ground water! :furious:

jomama45 12-06-2010 10:32 AM


Originally Posted by Gnfanatic (Post 546458)
Alot of you guys have stated several times in the past about the proper way to attack a water issue is from the outside. I agree with you 100% BUT what happens when you are like me and have flat property and no damn city drain in the front road?? where does the water go?so if I dig 8 ft deep around the outside perimeter of the house and I need to have a drywell thats at least 9 ft deep so the water is gravity fed, but then the drywell well will probably be full of water by then due to the hgih ground water! :furious:

Drywells are useless in 99% of the situations they're placed in IMO. There's ABSOLUTELY NO WAY I would rely on a drywell to manage draintile water, especially since the majority of that water is ground water, either natural or created by the huge hole in the dirt (the foundation).

The solution to this is extremely simple and proven: A complete draintile system, with interior & exterior draintile, stone and bleeders through the footings, all tied to an interior (or exterior depending on your locale) sump crock & pump. It's been done successfully in millions of homes for decades. As a matter of fact, our code in this state requires a sump crock (although the pump is discretionary) be installed in every new residence, even if you have a drain to daylight.

stadry 12-06-2010 06:23 PM

AMEN, brother - from your mouth to God's ear :thumbup: unfortunately for buyers of new homes, most bldrs' warranties only cover ' water intrusion for the 1st yr ( then out comes the hydraulic & prayers for a drought :laughing: ) usually the pipe's just laid into the dirt trench alongside the footer leading to daylight,,, here its filled w/silt w/i 6mos,,, thankful they don't install it correctly, tho - we need to eat too ! ! ! :yes:

when's the last time you saw a bldr compact the backfill ? ? ?

ConcreteTreat 12-07-2010 06:32 PM

itsrealyconc -- interior "waterproofers" know that it's not technically waterproofing. However, people see it and think "waterproofing", so they go ahead with it. You have to call it like people see it, or you're not speaking their language.

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