Basement Waterproofing

[EL72]

Anyone have experience with this type of work? As with most older homes, we have water (mainly rainwater) seeping in through foundation wall cracks at the back of the house. I have had a few bsmt waterproofing guys have a look and give quotes but there are many different fixes and types of materials. Exterior repairs (digging to the footings and waterproofing the foundation, installing weeping tile...) or internal weeping tile with sump pump. Some contractors go with the Delta dimpled membrane, others rigid styrofoam instead... Anyone here have any experience with any of this?

 

[Tom Bell-Drier]

the main criteria in deciding the method of waterproofing,is the area completely bellow ground, and subject to hydrostatic pressure,do you use the basement as part of the living accomodation or is it where the boiller is situated and mainly for storage, how much disturbance can you take, and the type of construction of the property. If you want to PM me I can advise you accordingly,as this is an area that I know a fair amount about as a property developer and specifier.

 

[MrRogers]

For what it is worth, my parents had the same issue in their home for almost 15 years resulting in a good amount of water in the basement everytime it rained heavy. patches from the interior would work for several months to a year only to eventually fail. Once the foundation was dug out in that particular spot and sealed from the outside, the problem was solved. You should also consider the grading of the land near that part of the foundation and if necessary install a proper drainage system that won't allow large amounts of water to collect near the foundation

Mrr

 

[Dakota rube]

MrRogers is completely correct in his statement(s).

 

[Manton]

If you waterboard in the basement, is it still torture?

Wait -- wrong thread. Sorry!

 

[EL72]

Originally Posted by Tom Bell-Drier

the main criteria in deciding the method of waterproofing,is the area completely bellow ground, and subject to hydrostatic pressure,do you use the basement as part of the living accomodation or is it where the boiller is situated and mainly for storage, how much disturbance can you take, and the type of construction of the property. If you want to PM me I can advise you accordingly,as this is an area that I know a fair amount about as a property developer and specifier.

Thanks Tom. The house is approx 80 yrs old and the foundation is concrete block. The footings are only 4-5 ft. below ground but the entire basement is finished with two separate apartments. Digging inside the basement will be far more disruptive than outside.

Despite the claims of some contractors, I am sceptical that allowing water through the foundation wall to gather through the weeping tile, only to be pumped back out is a good idea. Common sense just tells me that it's better to waterproof from the outside but I'm told this is rarely a foolproof solution either - unless you dig around the entire house, which is not really an option. I'm presently looking at digging up the entire back wall (30 ft.) + 8 ft from the corners on each side.

For the outside work, the standard material seems to be this Delta dimpled membrane that is wrapped on the foundation wall below ground but some contractors are suggesting other materials like a stick-on rubber membrane or rigid styrofoam. Do you know the pros/cons of the different options. Thanks!

 

[GQgeek]

Originally Posted by EL72

Thanks Tom. The house is approx 80 yrs old and the foundation is concrete block. The footings are only 4-5 ft. below ground but the entire basement is finished with two separate apartments. Digging inside the basement will be far more disruptive than outside.

Despite the claims of some contractors, I am sceptical that allowing water through the foundation wall to gather through the weeping tile, only to be pumped back out is a good idea. Common sense just tells me that it's better to waterproof from the outside but I'm told this is rarely a foolproof solution either - unless you dig around the entire house, which is not really an option. I'm presently looking at digging up the entire back wall (30 ft.) + 8 ft from the corners on each side.

For the outside work, the standard material seems to be this Delta dimpled membrane that is wrapped on the foundation wall below ground but some contractors are suggesting other materials like a stick-on rubber membrane or rigid styrofoam. Do you know the pros/cons of the different options. Thanks!

My parents spent over 50k (maybe more) trying to seal a basement that was flooding and the house wasn't nearly that old. I know absolutely nothing about any of the methods used, but my point is that nothing ever works-out like contractors say it will. Ask what kinds of guarantees they provide if it starts letting-in water.

 

[Dakota rube]

Originally Posted by GQgeek

my point is that nothing ever works-out like contractors say it will. Ask what kinds of guarantees they provide if it starts letting-in water.
Actually, I have a couple friends who are in the basement repair business around here. We live in incredible muck; when it gets wet, it stays wet. There is almost no sand content to the soil, so natural percolation is almost nil.

My friends have had great success in this quite challenging environment by excavating around the entire perimeter of the foundation, down to the footings, and installing drain tile to collect and divert the water away. The foundation is then waterproofed using several different types of membranes. The excavation is filled with rock to facilitate water traveling downward to the drain tile.

Then, as MrRogers said, make sure the earth is properly sloped away from the foundation. And that downspouts are extended to carry water from the roof away from the foundation.

 

[Tom Bell-Drier]

EL72.
your commonsense is correct that digging and waterproofing with a membrane externally would be the best option,however to achieve this aim correctly the entire area of ground around the wall would need to be excavated not only in a horizontal plane, but in a vertical plane to eleminate the inherent risk of strike back moisture and the abillity of the local water table to rise, in an established property this age ,to undertake this method of waterproofing is not only time consuming but can lead to more problems than it cures.

the problem with stick on rubber membranes and rigid styrofoam products (known as tanking membranes) is it allows moisture to permeate the externall wall but stops the moisture reaching the internal surface (this in its self is a good thing)
however problems occour when the water meets the membrane, capillarity/osmosis (the method by which moisture and water vapour makes it`s passage through solid concrete ,brick, stone etc) can cause the water to migrate from the initial site of penetration. and account has to be taken of the condition of the substrate of the wall to ascertain the suitabillity for adhesion ( are there undulations in the wall that will allow gaping in the wall membranet hat will allow water concentration to occour leading to damage of the membrane particually at the wall floor junction ( how does the contractor propose to seal this junction- a notorious weak spot). furthermore if the membrane is damaged during or after installation the system will fail.

the delta system in my opinion is the way to go in your circumstances, a delta system works on the principal of controlled ingress of water along with controlled evaporation.

the membrane which has a dimpled back and is secured to the wall with self sealing fixings and joints overlapped and sealed with butyl rubber.

once the membrane is affixed a new section of drywall can be formed to form a structure independant of the original wall.this should be vented at the top and bottom, to allow through ventillation and the basement itself should be installed with some form of mechanical extrraction to avoid the build up of water vapour leading to condensation in the basement.

if there is actual running water occouring an internal drainage system with a sump pump should be incorporated within the specification by the contractor.

if you know any friendly architects they should be able to advise you in more detail and should be able to recommend a number of specialist contractors.

my knowledge of basement waterproofing is from the British market where regretably we know a thing or two about rain and wet conditions.so much so that British waterproofing contractors are willing to issue a 30 year guarantee on an installed waterproofing system

it may be worth carrying out an internet search uk specific using key words such as:
waterproofing
tanking
damp proofing

and try and get in touch with the building research establishment in the uk .

these are the guys who spend their time in workshops and labs who licence all building products in the uk. on behalf of the government.

although a bit long winded I hope the above helps , and if you need any specific questions answering just post or pm me .

best regard TBD