After taking all sheet-rock down I noticed that all walls (cement block) siting under ground are moist. Some of them even ate through footers. After farther look at the house I found out that their is no insulation on the outside of the cement blocks that are under ground. On the blueprint of my basement I marked in red most affected areas or rather corners. This is walkout basement. My question is, should I try to divert water from the house by insulation/wrap and drain on an outside or French drainage on the inside? Also the whole house is on the slope and red circles are on the side that is deeper under ground. Thank you for all help.

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  • Have you digged down from the outside to see what is going on. It also helps to dry it out and see where the water issues start. it would also help to see pictures from the outside from different angles. This does not appear to be a water table issue – DMoore May 31 '19 at 19:19

Block walls will always leak if there is not enough drainage from outside the home. Since you have a walk out basement you will have a much easier time of fixing your problem. First you would want to try a shallow French drain around the premises, dropping down to the lower level and making sure you connect to any gravel at the lower corners of the home and continue down the hill a few feet and have the pipe exit at ground level, this will take care of runoff from the high side and help Chanel any slab back pressure down the hill. I have had 2 daylight basement’s or walk outs both that required a lot of work down stairs because of water damage. I installed a 4’ deep drain on the first home across the front and down the sides it was dry for 13 years when we upgraded, the second was an older home with 2 sides below grade and damage close to the below grade corner, this home I installed a 3’ deep Drain and it did the job. I did add some weep holes next to the below grade garage outside in the retaining wall (as I later enclosed this and opened the basement to make a huge man cave) that area never had problems after ~8 years , my daughter lives there and it has been a few years since I moved ~+8 and she has not asked for any help so it is probably still dry. But that’s what I would do . Use heavy plastic sheeting from the siding under the pipe and gravel and then back up a foot or 2 this keeps the water contained and really helps. I have done this on 2 of my homes and over a dozen when I worked for my dad’s construction company.

  • Your system of installing a perf pipe only 4’ deep only works if it’s collecting surface water (rain water) or water from downspouts that dumps water out on the surface. It does not account for subsurface water or a rising watertable, which the OP clearly has. Look at the pictures and you’ll see the exterior wall is wet from the basement slab UP THE WALL. – Lee Sam May 29 '19 at 21:37
  • Seems like a bigger project that I can handle. Any recommendations for NJ company that could do that ? – Lukas718 May 29 '19 at 22:04
  • With daylight basement or walkout as they are called in my area only a diversion of the up the hill water is required, I have 2 personal , my homes that I lived in for years and my daughter still lives in today, on a hill or walkout or daylight basement there is at least 1 surface of the home that has below grade drainage below the slab by definition, any water that enters the lower level is from surface water or a spring and both have been eliminated from the many homes I have fixed , if you are a flat lander you don’t have a clue but I have owned and fixed homes in several states.- – Ed Beal May 30 '19 at 1:28

Moisture is either coming up from below (a rising water table) or its coming from the surrounding ground water in the saturated soil.

If it comes up from a rising water table, it will enter the basement space from below through the crack between the foundation wall and slab.

It appears from your pictures that moisture is at the BOTTOM OF THE WALL. Therefore, the perf pipe needs to be installed at the bottom of the wall.

If it comes from the surrounding ground water, it COULD enter the living space through the wall, especially if the EXTERIOR side of the foundation wall is not sealed properly. Either way the moisture enters the living space it will need to be collected and disposed. I think the best way to collect it is on the exterior side of the foundation wall in drainrock and a perforated pipe laid 6”-8” below the interior basement slab.

To keep the subsurface water from seeping through the wall, I recommend installing a moisture barrier on the exterior side of the foundation wall and install a 2” thick plastic mesh on the wall to allow water to flow down to the perf pipe. If dirt is allowed to be backfilled against the wall, the dirt could hold the moisture against the wall giving it a chance to seep through the wall.

Once collected it needs to be disposed by extending a solid pipe over an embankment or in a collection well and pumped away.

Remember, water flows in the direction of least resistance.

  • How can I find out if the water comes from below or walls ? It will be expensive for us to get that done on an outside so I wouldn't want to end up with another job to drain inside. – Lukas718 May 29 '19 at 17:48
  • @Lukas718 You don’t need to add perf pipe inside your basement, if water is coming from below. It will naturally percolate to the perimeter perf pipe. Just make sure the pipe is about 6” below the top of the slab. – Lee Sam May 29 '19 at 17:57
  • So it would be better to seal the outside around the house ? Should I leave gravel on the bottom and lay drain pipe around ? Sorry for so many questions but I'm super new to that and now kind of stuck with companies telling me to get French drainage in my basement which is over 14k that I didn't plan to spend. – Lukas718 May 29 '19 at 18:31
  • Yes, lay drainrock on the exterior of the basement wall and install a perforated pipe about 6” below the top of the slab and backfill with drainrock. I also like filter fabric to line the excavation. – Lee Sam May 30 '19 at 16:48

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