Latest Discussions : Basement & Foundation


08:32AM | 08/27/04
Member Since: 08/26/04
11 lifetime posts

I have a year-old townhome with a poured-concrete basement and it is waterproofed on the outside with some kind of green plastic coating (by the builder). I had one crack in an exterior basement wall, which I never saw leak, but got it pressure-injection grouted anyway (just-in-case). We have never had any water leaking or dampness on the inside, even with all the rains this summer (I live near Philly). The basement also has a sump-pump and an under-drain under the floor.

Now we are planning to finish the basement, and the contractor says that we dont need to waterproof the inside (with something like drylock). He plans to put the wood framing up against the wall, and says we will never have any water/moisture problems (we also have a dehumidifier currently in the basement). Is he correct? Should I still go ahead and dry-lock the wall just-in-case? He wont do it, so I have to dry-lock it myself. Or should I just paint it with regular latex based concrete paint?

Also, I found some conflicting advice on the internet with some folks not recommending dry-lok as waterproofing both sides traps the water in the wall and degrades it. Is this true? Also found conflicting recommendations about the use or not of vapor barriers and XPS sheeting.

I'm totally confused and any help/advice will be greatly appreciated.




05:58PM | 08/27/04
Member Since: 03/05/04
301 lifetime posts
congrats on yer new townhouse....NO, drylock will not do anything as to keeping water from coming through a crack, hole or any direct opening that is or may arise on the outside of your home in is impossible for any paint to stop water from entering through a wall or from water entering through windows, tuckpointing needs etc. As to your builder...he may be a great builder..doesnt mean he has the expertise of waterproofing. The ONLY way you can be assured that water will never come through the bsmt walls is to have the walls waterproofed from outside by means of hydraulic cement,Thick Tar & visqueen and backfilled with pea stone/gravel from the footing all the way up to within 6-8 inches of grade. All epoxy injections of cracks in poured walls i`ve seen have re-opened because of further settling or from hydrostatic pressure which exists on the outside of the walls caused from heavy soil/clay and/or from roots as well, which can buckle,crack any wall over time. Your sump pumps only use is to control the water level under the floor, it has no other use. And doing any inside water-diverting method (B dry,Everdry etc) does NOT stop water from coming through walls,it only diverts the water that has already entered under the floor. So it then cannot prevent mold and/or efflorescence and it doesnt take hydrostatic pressure off the outside of the walls, only an outside method(done correctly!) can stop water which will then prevent mold etc. The ONLY time i would do an inside method is if there is an addition/porch on the outside of where there is a crack on the inside of wall...rarely! IMO..lose the vapor barrier thought, GL!


08:38AM | 08/28/04
Member Since: 08/26/04
11 lifetime posts
Thanks for your very informative reply. My basement is already waterproofed from the outside. I'm not sure what they used, but its green and looks like some rubber/plastic either sprayed or coated on the outside.

My question is: given that its already waterproofed on the outside, should i waterproof the inside too? Some people recommend not waterproofing the inside as it will trap any water in the wall and degrade it.



05:21PM | 08/28/04
Member Since: 12/09/03
175 lifetime posts
Ask the builder if he installed a drain at the base of the footing on the outside [that is a pipe; I'm not happy with the plastic sheeting answer] and ask him where that water drains to. Also watch the pump during wet seasons. Is it pumping water from the hole? If so install a battery back up pump. If the water flow is real heavy [10 gallons per minute or more] put in a second pump next to the first one & an alarm. If a pump craps out down the road,you'll be glad you did this. If I were you wait a year before finishing the basement. Just to see how things go, and you'll be more sure of your new place.Good Luck. C.


04:35AM | 08/29/04
Member Since: 03/05/04
301 lifetime posts
you 'dont' know if the outside was waterproofed "correctly" what i`m saying...a sprayed or rolled on amount of liquid tar on the outside of walls(which is prolly what they used) will NOT last too long! That is like applying a coat of paint.....Thick Tar is Best and lasts very long time and as always backfilling with all pea stone/gravel is best...NOT dirt/clay! I say yet again..sounds to me as if it was not waterproofed on the outside as it should have been...ya folow? Cellarwater is right on about having a battery OP back-up....some homes in certain areas and certain size homes need 2 or even 3 Sumps. IF your sump can handle large volumes of water AND the waterproofing was done and correctly backfilled on the outside then should not need anything done on the inside! Thats a BIG IF !


09:49AM | 09/14/04
Member Since: 09/13/04
2 lifetime posts
I want to protect my basement from water. I will be digging out around the foundation. Do I need to hydraulic cement all foundation walls? They are block walls. Also what is the Thick Tar that you say should be used? And if I do this approximately how long will this waterproofing last? Any other information would be greatly appreciated. Thanks.


01:40AM | 10/31/14
I do not recommend using dry lock if your goal is to block water from entering through the materials. Dry lock traps moisture and fluid substances into it that cause damage to the walls. Sheet membranes can do the job for you because they were made for horizontal and below-grade sites or any areas that are difficult to reach. Learn other waterproofing methods from waterproofers Sydney –


11:46AM | 02/26/15
I have a similar situation. Our house was built in 2004, and looks like it was correctly waterproofed on the outside (w/ black tar like coating) and have rigid insulation around the outside of the foundation. We have no holes, leaks, or any water problems on the inside. Before finishing, should I still use drylok on the inside of the poured foundation walls? I don't want to deteriorate the concrete walls by coating both sides, is that what would happen?
Thank You!!

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