Basement waterproofing evaluation

Old 06-03-19, 05:32 AM
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Basement waterproofing evaluation

Hello folks - I purchased my house in Aug 2018 in NJ. It is a single family two story home with a basement. The house was constructed in 2000. It has a sloping backyard elevation coming to the back of the house. The previous owner had a partially finished basement. I recently started a basement finishing project. The contractors finished the demo over two days. When they completed the demo we found a few water marks on the basement wall at the front of the house and the back of the house and towards the floor. The contractors are recommending water proofing and therefore we have put the next steps of construction on hold.

I have talked to original owners in my neighborhood and none of them have had basement water issues. This house has also not had any my knowledge. However the evidence of some marks and the previous owner having used some kind of water blocking paint on some of the walls and the resultant efflorescence at particular spots concerns me.

I had a few waterproofing companies come in to assess the situation. All of them sell a system of interior French drains and all of them are recommending installing them and cost is between $8000-$12000. None of them want to deal with any prevention on the outside.

I posted my issues in the AVS forum (because I was discussion theater construction for my basement) and their opinion is that I do not have a severe water issue and that I need to take steps to stop the water coming towards the house. The recommended steps are:

1. Install downspout extensions (preferably under the ground to route water away)
2. Add soil and gravel with a slope grade going down leading water away from the house
3. Dig up a horizontal trench at the back of the house with tubes running under that will route any water away and to the side of the house. Preferably tie #1 and #3 together
4. Apply Drylok

I have already done #1 although it's overground. None of the basement waterproofing companies have suggested the above options. My concern is that if I do the above steps and I have issues after I finish my basement what do I do as it will be too late to break open the walls and install an French drain system. On the other hand is it an overkill to spend $8000-$12000 on something that making external improvements could curb? Also wrt point #4 above I have seen some negative reviews on the usage of drylok and seeing some of the flaking and efflorescence on the current walls, I am a bit doubtful about using it. Additionally even if I install a horizontal French drain outside, how will it stop any water from the deck?

Can anyone please help me in understanding what I should do? If you are in New Jersey it's even better. I appreciate your help. I have posted a video walkthrough and pics as well.
Old 06-03-19, 10:44 AM
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I had a few waterproofing companies come in to assess the situation. All of them sell a system of interior French drains
FWIW, this is water mitigation, waterproofing is done on the outside, as you have proposed. I like your plan and I don't get hung up on downspout extensions being above or below ground. I would go with your plan but put the basement finishing project on hold to evaluate the results of your work outside.
Old 06-03-19, 11:22 AM
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My own personal experience is that Drylok is completely worthless on the interior of basement walls.

It sound like your water infiltration is pretty minor and that surface mitigation of water runoff as described in 1,2,3 will probably be sufficient. On #2, just use soil to slope away from the house - no gravel. Gravel would only be needed if you have a spot that cannot drain by gravity and you need to dig a dry well. Can you tell if water is actually seeping in through the wall or is it condensation?

Do you have a sump pump and is it in good working order? How often does it run? Does the discharge drain some distance away from the house?

I would consider renting a bobcat and forming a drainage swale at the base of the hill that runs to whichever side of the front yard is lower. That way you can direct runnoff from the hill and from the back of the house away from the foundation.
Old 06-03-19, 03:07 PM
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Thanks. I do not have a sump pump. When you look at the pictures and videos I posted do you think it is conndesation or water coming through the walls?

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