Wet basement wall

[ras]

If a basement systems waterproofing system -- which eliminates the water from the inside only -- is used to remedy water from seepage through a stone foundation, does one run a risk of weakening the foundation wall? Is there something that should be considered in addition? I would reallyappreciate this information before I decide what to do.

[Mark]

With any interior system you are really just controlling the water. Keeping the floor dry. With a stone wall the only other option is to completely excavate the outside perimeter, parge the wall with a cement coating, apply a waterproof membrane and install some type of drainage system. I dont know if anyone can be certain about the integrity of a stone wall. But I will say that I have never seen one fall apart. A few things that can be done to help are to extend downspouts at least 10' from the home, make sure grading around the foundation is pitched away and if you decide to go with the interior system I would recommend a vapor and moisture barrier on the walls the directs any seepage into the sub floor system.
Thanks
Mark Daconto VP
Basement Systems Inc.

[Beano]

ras,

it appears as if the administrator of this page has very little knowledge on the topic of waterproofing. interior waterproofing is one of the most ridiculous ideas that customers have ever bought into! why would you want to deliberately allow water to enter your home? this will only weaken your foundation over time. and anyways, if there is a proper method to stop it from entering to begin with, wouldn't you rather choose that method? i assume that the stone you were talking about is the backfill around this house. when waterproofing is done correctly, draintiles are laid around the foundation, the wall is sealed, and gravel is backfilled almost to ground level. the purpose of this gravel is to allow water to percolate easily to the draintiles, without giving it a chance to divert anywhere else (i.e. basement walls). when there is not any stone backfill, just dirt, the water has nowhere to go, and hydrostatic pressure build up very easily and quickly. This is a powerful force, and most people do not understand it's intensity. if you have a 5' deep basement, hydrostatic pressure can be as strong as 780 lbs per linear ft. so a basement wall spanning 10' @ 5' deep can have almost 4 tons of weight pushing against it! that is why interior waterproofing is a terrible idea. not only are you allowing water into your basement, you are not alleviating this pressure. it is a must to repair from the outside (place draintile, seal the wall, BACKFILL!)

[Mark]

Beano,

Having succesfully fixed over 15,000 homes from our local office I think we are very qualified. I'm not sure you totally undersood the question. When we speak of stone foundations we are talking about foundations built 70 or more years ago from field stone. Some have mortor and some are dry set. When these homewere built they used the virgin soil outside the wall as support for the stone walls and packed the stones directly against the soil. There was no excavation, waterproofing or drains installed. In most of these cases there are voids and cavities in the wall that could never be sealed when the wall was built. To excavate the walls on the outside could be dangerous.

The other question is since most lots are flat or dont have enough fall or pitch where do you drain the exterior draintile. If you bring it into the basement to a sump arent you contradicting yourself "to deliberately allow water to enter your home?" It has to drain somewhere? If you allow it get to the drain and sit there you are correct the water is a powerful force and the hydrostatic pressure will build greatly and cause problems.

We also beleive in building basement the right way from the begining. Check out the Fine Homebuilding article on the web site. It talks specifically about what should be done to waterproof a basement from the outside.

[Beano]

sorry about the stone foundation. you're right, i did misunderstand the question. these cases, although rare today, can be corrected. like you said, all the gaps must be filled with cement, until the wall is smooth. then it can be waterproofed normally.

in response to the sump pump question. whenever possible, the system should drain by gravity. there is no reason to have a mechanical device installed, which can malfunction, unless completely necessary. unlike manmade devices, mothernature is constant, so you should take advantage whenever possible. however, in the occasion where the main storm is above the foundation of the house; then yes, a sump pump is required. This does not mean that the water has to enter the house. like i stated before, all correct waterproofing is done on the outside. in these scenarios, a manhole can be installed where the storm main reaches the house. also, inside a manhole, the entire system can join. this will provide access when cleaning of the lines is necessary. the manhole can easily be concealed by dirt for a flower bed or grass.

i understand that your company has done many homes from the interior. waterproofing, although it has been around by a long time, is still a process that is unclear to many people and companies. the problem is that it can be a very sensitive process. an unprofessional can easily make a mistake during installation that will cause the system to fail. unfortunately, it is much easier to design a waterproofing system during new construction than to fix an existing problem. this can be very expensive. this is why most homeowners resort to the cheaper solutions. however, like i said, these are temporary solutions. allowing water to enter the home only weakens the foundation. and anyways, why would you want water running along the base of your basement walls? i know i dont want that in my house, and i know that i also dont need that in my house, nor will i ever, because i had it waterproofed correctly from the outside.

i was unable to find the Fine Homebuilding article you spoke of; however, i like the sound of it. when building a new home, waterproofing is one of the most important aspects. it is something that if done incorrectly can costs a lot of money in repairs and damages, and also weakens the integrity of the home. in new construction, if done correctly, the system should last the life of the home.

thanks