Bentonite injections around foundations

[davidmklein]

Can anyone tell me if injections of bentonite into the soil around a foundation is a reliable method of waterproofing?

[dale grafton]

I am also looking for information on high pressure injections 6-7 ft. deep around foundation, to waterproof minor basement dampness; if I find any info, I'll pass on to you.

[claire]

I too am looking for information on this option for waterproofing my basement. I've gotten alot of conflicting information about the substance (Volclay) which is, I guess, the trade name for sodium bentonite. If anyone has information, I need it in a hurry! Thanks.

[dale grafton]

Hi Claire:
An old, but proven product for interior masonary application (block, brick, poured concrete) is a product called Xypex. They have a website.

An old mason contractor customer of mine (I sold scaffold, constr. equipt.) had picked this product as a sales (distr.) sideline & he was impressed. A quick explanation sounds like snake oil, but truly, it is effective. A brief explanation follows:

The Xypex (dry grey cementaceous powder) is mixed with water and the thick slurry can be brushed onto bare, clean masonry surface. When the moisture penetrates the deep voids of the porous, it contains a chemical which when left to dry, grows and fills, as a "crystalline" substance, making the previously porous surface, non-porous. This prevents water from entering that face.

Coincidently, I had this applied (interior basement) when my house was built ('73) and it worked quite well. My present problem is minor with just efflorescence, no real moisture.

Therefore, I'm looking to have a test patch applied, after proper preparation ( perhaps power brushing, scraping to remove powdery material), then have this water mixed paste applied like peanut butter, with a flat trowel or wide putty knife, perhaps two coats and wait a few weeks to paint, then wait to see if efflor. appears again.

[stevea]

Dear Claire,

I am the founder and current President of Pioneer Basement Systems in MA. I have over 20 years experience in the waterproofing industry. I served as the President of the NAWSRC in 2000 and 2001. I would not recommend injecting bentonite along side your foundation.

While in New Construction bentonite has its place, I would not recommend injecting it into the ground along the foundation. For many years I have seen companies sell this type of waterproofing solutions and also have seen the problems it creates. First, no one can be sure that the injected material will seal every area of the footing and foundation because of debris, tree stumps, rocks , etc. may be backfilled around the foundation.

Secondly, The injected materials has been known to eventually clog any existing drainage system around the footer of the house, thereby making the problem worse. I would recommend that you contact me directly at stevea@pioneerbasement.com and I will provide you with more info on this subject,or you may call me at 1-800-649-6140.