Are you trying to solve a current water problem?

You need better clarity on what the contractors are proposing.

What kind of plastic sheeting???

If it's polyethylene, for instance, that lasts about two years outside, less if exposed to sunlight.

If you already have an active leak, re-grading alone may not be the cure.

Hi, thank you for all your comments! The gutters are in good shape. We have gotten some water intrusion under the porch when we were not able to keep up with gutter cleaning. It is not clear if the ground under there is sandy or not. The other area, we have some areas of the ground that's lower near the house where water tends to puddle, although we had water intrusion from there only once in 11 years when there was significant rain and snow melt at the same time. We have downspouts in appropriate areas. Overall, we don't expect water intrusion as long as the gutters are clear, but we have an opportunity now to have some landscaping done to add some more protection. Just wanting to know which method is better out of two quotes. I'll ask what kind of plastic one of the contractors plans to use - what kind would be acceptable? Is class 5 gravel and dirt or only dirt (with grass) generally good materials to use?

Unless the soil under the rock is contoured to direct water away from the house, the rock will only create a hidden place for water to pool. Soil grading is probably what you really need with some vegetation or mulch to prevent erosion. Minnesota building code requires the final grade to slope away from the house at least 10’ out, dropping at least 6” in that 10’. Code is minimum. You can do more if you prevent erosion.

Thank you! So perhaps no gravel (under dirt) but sticking with soil/dirt would be better. Hopefully grass (seeding) will be enough vegetation you mention to keep it from erosion. I will have to ask about the plastic sheet below the deck (what kind). I wonder why the contractor says they use class 5 gravel for grading all the time. Is there "class 5" for something else that is not gravel?

Neither scenario is a solution to basement water infiltration.

- #1 Contractor exposed plastic under deck - why.

- #2 Contractor grass seed under deck - why.

- #1 or #2 Contractor, don't know which "Class 5" gravel is associated with - use when you want a solid base. Why do you need that with a top coat of soil? So adding minimum 8" continuous?

Not enough info given: height of deck, the problem at the low spot, the surrounding grades, where water can go . . . .

The others mentioning downspouts is in reference to the leaders and exactly how far away they discharge from the house.

Thank you for your response! Deck is about a foot or two high with barely a crawl space under it. We are removing the deck boards for another reason, which prompted the idea perhaps we should have some water grading work done at the same time. So plastic will be exposed under the deck but not really exposed once the deck boards are put back on. But we asked if anything should be put on top of the plastic and the contractor did not seem to think so (DK if this was a correct response). Grass seed is for another area (not under deck) with the same contractor.

Contractor #2 wanted to use "class 5". Seems like if it is gravel, it is not appropriate unless you can add at least 8 inches of top soil??? We got a sample of material what the second contractor said they would use. We were told to try adding water to it. It looked like it was made of some rocks and finer particles, and after adding some water, the particles seemed to have hardened, kind of cement like. Is anyone familiar with this?

Downspout was extended recently to where another contractor who was doing unrelated work thought was appropriate distance from the house (I cannot check the length right now). I'm not sure where the water would go - if the grading was done out 10 ft from the house, I guess it will end up puddling 10 ft away from the house where the grading ends...? One of the depressed area (not under deck) is actually a cement slab, which we don't know why it is there, but is lower than the surrounding ground there and water tend to puddle there after rain. I wonder if it would be a problem to cover it up with soil to create a grade?

Unless the ground around the foundation is graded for a drop of 1" per foot over six feet, layers of polyethylene--which I suspect is exactly what the "contractor" is planning to use--and all the other odd assortment of materials will do next to nothing to help drainage.

See video illustrating the grading.

Thank you. I will ensure that they do this at least 6 feet out (totaling at least 6 inch drop, it sounds like)!

"Deck is about a foot or two high"

Plastic is fine, but that is just for housekeeping and maybe to limit moisture rising up under the deck. It doesn't really contribute much in preventing a basement water problem.

"class 5"

That is your regional term for a gravel mix. The "Class 5" refers to the size of the crushed rock in the mix, up to 1" large. There may be many types of mixes available in Class 5 - e.g. decorative red limestone, recycled concrete, granite, etc. - it sounds like your contractor's version is rock with a sand/clay mix in it. The fines allow it to compact well, which is why it is used for exposed driveways and pathways. The 8" total I referred to was from 4" gravel (minimum required to compact) + 4" soil (minimum to allow grass to sustain itself over time). From what I guess, the contractor is trying to use the gravel as a "cap" on the ground to help in preventing basement water intrusion. This does not work, as water seeks level and will run underneath whatever "cap" is put there. So it can be gravel, steel, or a concrete slab, not much difference if you are having water issues.

"cover it up with soil to create a grade?"

Do not cover the slab with the depression. The water just penetrates the soil and will still sit on top of the slab. More info about the slab would be needed to understand that area.

"I guess it will end up puddling 10 ft away from the house"

That is a good generic distance for dumping the downspout leaders. However, a full review of the entire lot's grading should be done to make sure any water deposited has a place to go away from your house.

Here's a Minnesodah Class 5 that sounds like what your contractor is proposing, FWIW.

Thanks! From how the contractor described it, I was thinking gravel mixed with stone dust was what was being proposed. Looks similar to the link you've pasted above. He described it as getting hard when it gets wet, preventing water from getting through. What do you think of this kind of use for this?

Water still penetrates it. No reason to use gravel at all. See above about the "cap." If you want to have a worry-free basement, you have to holistically approach the entire grading and drainage plan, not just under the deck.