Waterproofing a basement

[kkcomp]

What is the best products for both positive and negative waterproofing on a block wall below grade basement foundation?

[doc henderson]

Most will put an elastomeric back sealer on it.  It becomes brittle over time and does not span cracks well for long.  I then put a plastic product call dimple board and other brands.  It protects the tar coating from scratches and abrasions.  It creates an air space so any water can go straight to the drain tile and keep the outer foundation wall dryish.  certainly no water can build "height" and develops hydrostatic pressure to work into the wall and through cracks.    The dimples are in a pattern and can be folded.  I used it inside the basement of the shop.  I folded up 4 inches on the wall and reflected it on top of the footing.  I concrete nailed 4-inch-wide expansion joint to hold the part up on the wall.  this left the 1/2-inch air gap behind and a path to the inner drain tile.  two sumps in the circuit.  if the basement flooded it creates a French drain around the perimeter of the basement floor when poured to the top of the expansion joint and dimple board.  The other key is eves with gutters.  final grade moving water away from the foundation.  I also have some 4-foot sidewalks along the perimeter with slope that keeps the water moving away.  I have yard drains at trough areas, that drain to the low part of the yard.  I have 3 acres and the high corner is 6 feet above the opposite low corner.  all gutters go into 4-inch pipe, and it all goes to the low spot in the yard.  just have to be careful when digging or grading.  thought about a big tank for gray water but too many details to worry about to set into ground like a cistern.

[Joe Hillmann]

Is it a house that is already built and leaking or new construction? 

If new construction the best method I have seen is; drain tile in a washed gravel bed at the foundation,then dimple board above that and back fill with washed gravel.  That way any water can flow through the gravel or between the dimple board and cement to the drain tile and be pumped out or drained to daylight.

If it is a repair on an existing house I don't thing there is anything you can put on from the inside to stop it that will work well.
Digging down on the outside is the only way I have found to actually stop water from coming into a basement.    Although directing water away through landscaping and gutters with down spouts that get the water a long way away from the house can do a lot to reduce how much and how often water gets into the basement.

[NE Woodburner]

If you have tight, poor draining soils and have a real concern with future issues, it may be worth installing a membrane like Bituthene then use dimple drainage board. Put in a perimeter drain backfilled with crushed stone and use a well draining gravel to backfill the foundation. Daylight your perimeter drain.

[YellowHammer]

I have had several below ground storm shelters that flooded every year until I swabbed on a couple coats of Damptite on the surface of the interior cinderblocks.  Not more leaks. 

[rusticretreater]

Along with the drain tile and dimple boards, here is how we did it when I was a laborer on a construction site.  The foundation from the footer to the soil line was covered in a layer of hydraulic cement.  Then a contractor would come in and spray a tar coating over the whole surface.  While the tar was still hot, a sheet of thick plastic film was laid over that.  Seems expensive when considering the initial cost, but a dry basement for 20-30 years minimum is the result.

[barbender]

 I've done re-waterproofing on many, many basements in the past. I can't stress enough that the best basement waterproofing is proper grading and drainage of the site in the first place. Keep the water from getting next to your foundation I'm the first place!!

  I've seen people ready to go through whatever I recommended, costing thousands and a major disruption to their home and yard during the process, while half the yard drains right at the foundation and the area directly around the house is all sloped towards the foundation walls. Take care of the easy stuff first.

That said, I've had good results with the bitumen/poly sheet product, the name of which escapes me at the moment. It is about 3' widen and installed vertically. Once it touches itself you will not get it back apart. Back when I was first doing this type of work with my Grandpa, we would roll tar on the foundation, and then put heavy poly sheeting over it. This product is basically the same thing but far easier to install, IMO.

You want any water that gets next to the wall, to make its way down to the drain tile that you should have as quickly as possible. In heavy soil, it's beneficial to use a perimeter of sand or rock right next to the foundation to expedite the water getting down to the drainage later. Obviously this is more feasible with new construction.

Water always takes the path of least resistance, do your best to give it one that doesn't come through your house.

If your basement is below the water table, good luck. Get a big sump pump and have a spare on the shelf. There's nothing that will stop that much hydraulic pressure, IMO

[kkcomp]

Replying to some questions. New construction, house will be into the side of a hill with about a 5% grade that ends in a lake. Was already planning to use the drain tile with holes and a sleeve at the footer. Good idea on the sidewalks all around. Is it worth it to add any of the paint on stuff? I am not sure about tar, It works but there are environmental issues especially with the lake below. Same with the rubberized or Bituthene stuff but it is claimed to be not as bad.

[beenthere]

Would be great to go back to the fall of 1967 when I was having a contractor dig my house basement, who then sub-contracted the job to someone who didn't have the right equipment, who waited until below zero F temps to dig the foundation footings. Then the foundation footings were poured with no reinforcing rods, on which the foundation walls were formed and poured for the house to set 12" below planned. Again, errors made in below freezing temps. Can't recover from those mistakes, but adapt as best we can over the years. Maybe having inspectors are not such a bad idea, but would delay the project and cost a lot more.  : :
I tarred the new concrete walls before backfilling, but after 30 years, the water was beginning to find its way through the walls and into the basement. The expensive digging in the yard happened a bit over a year ago (fall '22) and drains to daylight were installed. 55 years now and hopefully good going forward.

[kkcomp]

Would be great to go back to the fall of 1967 when I was having a contractor dig my house basement, who then sub-contracted the job to someone who didn't have the right equipment, who waited until below zero F temps to dig the foundation footings. Then the foundation footings were poured with no reinforcing rods, on which the foundation walls were formed and poured for the house to set 12" below planned. Again, errors made in below freezing temps. Can't recover from those mistakes, but adapt as best we can over the years. Maybe having inspectors are not such a bad idea, but would delay the project and cost a lot more.  : :
I tarred the new concrete walls before backfilling, but after 30 years, the water was beginning to find its way through the walls and into the basement. The expensive digging in the yard happened a bit over a year ago (fall '22) and drains to daylight were installed. 55 years now and hopefully good going forward.

Stuff like that is why I ask so many questions.

[newoodguy78]

Being new construction the best money you can spend towards waterproofing the basement is hiring a reputable excavation contractor. All the coatings you can possibly buy will never outdo a properly drained and graded building site IMO.
After spending years in the carpentry trade building many houses the thing that always gets me is a building sitting in a low spot, placing a building and setting the elevation of the structure in such a way that the water runs away is key.
If your site doesn't have good perkable soil to backfill with request the foundation be backfilled with sand. Like was mentioned above water takes the path of least resistance. Things like this add to the cost but in the long run it's better and cheaper with much less aggravation down the road.

[barbender]

 I also worked on a grading and asphalt paving crew for many years. In that I got to see many, many more (and deal with) examples of improper siting and elevation. If you are trusting an excavation contractor to know how to do it, in my experience 90% of the time you will be disappointed.

You need to have a site plan and drawings for a contractor to go off of, and be able to hold them to it. If this is outside of your experience, it would be money well spent to have an engineering/surveying company do it for you.

[Ljohnsaw]

Setting up the drainage is the most important. But for extra insurance, you could put a layer or two of Thoroseal. I put that on my block after a stucco coat in the below grade areas. Thoroseal is a breathable waterproof cement product that should have no environmental impact.

[thecfarm]

Drainage and sand.
I am lucky. My house sits on a small knoll. Everything drains away from me.
but saying that my place is back filled with sand. The basement walls is painted with some black stuff and have never leaked.
The only problem I had was a crack in the basement wall. A hard rain in the summer time would cause water to come in to the cellar. This would be a shower in the summer time. Would not be much, would hardly even get the floor wet. I tried a few things, but what worked was a gallon of roofing tar. I dug out the spot, all sand and spread that gallon of tar over that crack. Had to just about stand on my head to get to the bottom, but been at least 10 years and not a drop of water has came in.

[barbender]

 I wasn't aware if any environmental issues with the waterproofing products. Any of them done properly are basically sealed to your wall.

[Tom King]

tried to post reply, got database error message

find Basement Waterproofing page on my website. 

try historic-house-restoration.com

that job in 2011.  links may be dead but Voltex DS still available

drain pipe out to daylight downhill.  dust dry in basement since

Link to Voltex DS.   This stuff works.   https://www.mineralstech.com/business-segments/performance-materials/cetco/building-materials/products/waterproofing/voltex

It's not cheap:    https://www.whitecap.com/p/cetco-voltex-ds-4-ft-x-1412-ft-bentonitegeotextile-waterproofing-liner-4-ft-x-1412-ft-roll-36161/voltexds/257vvds415rl

[Don P]

I think we've all been describing dampproofing, which is all I've ever done. Back in the day 3 coats of hot tar with 2 layers of felt embedded in the tar was very good. I don't think anyone does it anymore. The tar babies had to light the kettle at least once it seemed like. I do cold foundation tar with 6 mil most of the time but use dimple board if it looks damp. Drylock on the inside helps but nothing will stop hydrostatic pressure (a head of water on the backside) It has to be drained to just damp soil. Thoroseal works, enka drain... lots of options. local knowledge is invaluable.

On the socked drains, that is not a code installation. Fines can clog the small sock and then the drain is shot. I use wide landscape fabric to line the trench, drop in the slotted or perf pipe. Bury in clean 57 stone ~3/4" rock. and wrap the fabric over the stone making a big sausage. Take that to daylight or a sump pit.

[Don P]

Another one to consider is Superior Walls precast foundations. If there is a plant in range check it out. Do compare apples, it is insulated, studded out and has electrical chases installed. They crane them in in a day and you build the next. I did not dampproof the 2 I've done, as per instructions. It is 10k psi concrete and dense, get comfortable before drilling thru it!

That took about 6 tries, "select all" and then copy your posts before posting. if it crashes you still have your post to paste and try another way.

[kkcomp]

Thanks for all of the great feedback and suggestions. Please keep them coming. I was able to get to the site this weekend just after some good rains and observe the natural flow around the intended site. Based on what some have said I have tweaked the location a few feet and still maintain the view I want. There is a Superior walls location for my area so I will have to do a cost compare on them. I have also considered tilt up wall construction as well due to products mentioned. 

[711ac]

I wasn't aware if any environmental issues with the waterproofing products. Any of them done properly are basically sealed to your wall.

....and I'm sure that actual petroleum based asphalt has been a thing of the past for years.
Like many have mentioned above, the first, best prevention is keeping water away from the foundation. 
Positive draining (grading) and gutters.
Next is drain tile (at the footer) around the perimeter to "daylight"
Then choose your block sealant or "system" and backfill with something that allows water to hit your drain tile without a fight!

[SwampDonkey]

Drainage tile at the bottom around the perimeter out to daylight. 4 feet wide drainage stone from top to bottom of the soil profile adjacent to the foundation walls. Put in drainage lines for sewer and basement drain. Packed drainage stone under the slab, poly on top, then pour. Land sloping away from building and on the level some stone in deep under lawn soil not just superficial.  Have never had a drop of water enter the basement.

[KEC]

My home is a log home on a block wall. Used to get some water coming in near a small front porch below a roof valley. I removed the small porch and built a new one along the length of the front of the house. The new porch roof puts the water from the house roof out into the yard away from the house. No more water comes through and the front of the house is now kept dry and not rotting out. And, I get to sit on the porch and watch the birds in the shade. I wish I had a porch around the whole house like that. I used rough cut lumber, hemlock and larch from a local small mill. I used lumber of greater dimensions than called for, I like overkill.

[KEC]

Also, along these lines, Know that if you run a drain "to daylight" that you should screen the end of the pipe. I had a rat get into my basement via a plastic drain line, I know of weasels coming thru a drain line to the sump and into the basement and muskrats will go up drains and sometime die in there. As to concrete below a drip edge, the guy who built my garage put a walk in front of my garage and a ridge of mortar by the overhead doors so water would not run in. Water off the roof splattered all over the wall and the overhead doors. It ran down the doors and into the garage inside the ridge and it rotted out the lower part of the wall. I spent much of my first summer in retirement tearing off the lower part of the wall, filling the block wall with mortar, building up the block wall 4" with 4" solid blocks and rebuilding the lower part of the wall. My neighbor and I rented a concrete saw and cut away part of the concrete walk and got rid of it. I put #1 washed stone in its' place. Water now does not splash,  it just goes down thru the stone. Garage floor is now dry and my new wall stays dry.

[SwampDonkey]

Also, along these lines, Know that if you run a drain "to daylight" that you should screen the end of the pipe. I had a rat get into my basement via a plastic drain line, I know of weasels coming thru a drain line to the sump and into the basement and muskrats will go up drains and sometime die in there. 

Yep, definitely want a screen on there. This place is crawling with mice. That's why I have neighbor's cats and fox in the yard. Lots to eat. :D

And yeah, I even left drain stone uncovered here around the house. I don't want nothing interfering with drainage. I don't even want a plant or bush near the house.

[Don P]

A couple of schools of thought on running the drainage stone up to grade. That can invite water down along the wall that could be directed away by a sloping cap of soil over the drain stone.