Basement waterproofing exterior

Old 11-10-18, 11:44 AM
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Basement waterproofing exterior

If anyone is willing to offer some professional or personal experiences regarding basement waterproofing, I would be appreciative of all input. If I'm going through all the mess and expense, I just want to make sure everything is done appropriately and not just done the quickest and simplest way to get it done.


I'll be having it excavated to the footing, scrape then power wash the foundation walls. After drying, applying waterproof foundation coating. Over that using a dimple drainage board on the wall. On the ground It'll be about a 2 inch layer of rocks and putting 4" perforated PVC pipe then doing about 18 to 24 inches of rock over top of the drain pipe. Then covering the rocks with a Geotextile fabric before filling in with dirt.

My biggest hang up is what foundation coating should be used? From reading it seems suggested to avoid the tar and fiber/nonfibered asphalt based coatings of the past, and instead use a rubberized coating? Any input on these 2 products, or recommendations for other budget friendly effective coatings? My feeling is that I'm also using a drain mat so I don't need the absolute best most expensive foundation coating.
Old 11-18-18, 04:45 AM
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we do this work almost weekly & use basf's 'hlm5000'
you won't find anything acceptable at either the apron OR vest store
protect hlm w/miradrain or equal
probably too late for you but others may read this thread
Old 12-12-18, 03:07 PM
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You have two links listed above. One is a dampproof product (tar) and the other link is a waterproofing product. Depending on your wall type (block - parged,non-parged, poured wall, ICF, precast) might determine what type of foundation coating you want to use. Reading your questions above and knowing it's an existing foundation I would presume it's a block wall. After you remove the dirt I would first recommend inspecting the block and mortar joints for cracks. Repair all cracks before applying a foundation coating.

I would not use the black material or your first link. Tar by itself is a dampproof product which is fine. But tar won't last more than 5-7 breaks down. You will have to do this project again if you use tar. Your second link Gray Shield I've never heard of. Make sure it's ICC approved ( The Shield specs show you have to apply it at 60 mil. thick. That's a good amount of material required. If your locked on either of these two products go w/ the waterproofing product.

When researching foundation coatings make sure they are ICC approved ( This approval means it's been thoroughly tested and it's a reliable material. Then look to see if they are water based, safe and easy to apply, green, protects the entire wall both above and below grade. Take a look at Deco Seal Waterproofing Membrane. It's a little thicker than paint, it comes in gray or tan, coverage rate is 60 sq.ft per gallon and that includes two coats or 30 mil wet. A drainage board or roll-on membrane is not required over the Deco Seal after it's dry but it's recommended that an inexpensive board such as a white foam board 1/2" or thicker be used. This board will act as a protection board when stone is against it (as part of your drain system) and when backfilling occurs. Many grade types in the US are heavily clay based or have sharp aggregate (rocks/stones) so it's best for a board to protect your foundation coating. Be mindful of your grade away from your home and use down spout extensions to keep water away from your foundation walls. Good luck on your project.
Old 12-12-18, 05:12 PM
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FWIW, I am 30 years into the use of tar on my block foundation. I used a total of 25 gallons-to the point the later coats of tar would sag. After the tar set for a few days, I propped sheets of Styrofoam insulation to protect from rocks. I am surprised to read above that tar only lasts 5-7 years. In a few places I tarred too high and can see the tar above grade which appears to be in good condition. What's going on below grade I do not know except that I have no leaks.

Good luck
Old 12-13-18, 03:22 AM
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I worked for an outfit 30 yrs ago that dabbled in weatherproofing foundations. What we did was first apply a coat of stucco over the cinder block to fill the voids, once the stucco was dry we'd apply a liberal coat of foundation tar. I never heard of any failures although I think our work was only warranted for 1 yr. I know better methods/materials are used today but what we did back then seemed to work.

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