# Waterproofing A Foundation Wall With No Access



## dcbuilder (Jan 27, 2009)

Working on a new project with a difficult situation and would love to hear how other guys would approach the task. We're putting a large addition on a rowhome in the city. The addition has about 9 Ft below grade of finished basement underneath. The new foundation walls go right up against the left and right property lines and it is not possible to dig into the neighboring property. Both neighboring properties do not have basements so I'd be 9 feet below their walkout level. My foundation subcontractor is planning on doing a one-sided pour for the new foundation walls. He'll do this by putting plywood on the exterior side and then the form on the inside wall.

My question is: how would you guys waterproof this wall? I can't get to the outside, which would be ideal. The neighbors are not coopertive so this is out of the question. My subcontractor has suggested using marine grade plywood or plywood treated with foundation coating because the plywood will not be removed after the pour. He then wants to use drylock on the inside of the wall. We'll put a french drain and sump regardless of what we do.

Thoughts? It's not how I like to build a new foundation but I can't think of any better plan of action.

Thanks!
Dave


----------



## ohiohomedoctor (Dec 26, 2010)

You could purchase rubber membrane and run it on the outside of the form. The will waterproof without disturbing the neighbors space.


----------



## tgeb (Feb 9, 2006)

Something like this product would work a whole lot better than what your guy is thinking, (guaranteed failure).

There is another product that I recently saw that may even be better but can't recall the name.

You'll be looking at the 160R for your project. I have never used it but there are products that are designed to do just what you are wanting to do.

Oh, a new foundation sub might be in order, the one you have does not know what he's doing. Leaving coated wood underground in hopes that it will waterproof the new space is crazy.


http://www.na.graceconstruction.com/product.cfm?mode=c&id=79&did=11



> Structural Waterproofing - United States
> 
> 
> 
> ...


----------



## ohiohomedoctor (Dec 26, 2010)

tgeb said:


> Something like this product would work a whole lot better than what your guy is thinking, (guaranteed failure).
> 
> There is another product that I recently saw that may even be better but can't recall the name.
> 
> ...


That's what I said............. I think?


----------



## tgeb (Feb 9, 2006)

Here is more.

http://www.waterproofmag.com/back_issues/200711/blindside.php



> Blindside is often required on jobs where property lines and/or nearby structures limit excavation and access. Typical projects include “zero lot line” foundation walls, tunnels, and any jobsite in a high-density, build-up area.
> 
> Bentonite Sheets
> Bentonite has historically been the solution of choice for blindside applications, and products like the one Walton used are made by numerous manufacturers. Bentonite is still popular in blindside waterproofing because it has the ability to heal itself if ripped punctured, or cracked; and once hydrated, the clay is virtually impermeable to water and most chemicals(i.e., acids, bases and hydrocarbons).
> ...


I remember the product now. Voltex DS, or Voltex


http://www.cetco.com/bmg/VoltexDS.aspx

http://www.cetco.com/bmg/Voltex.aspx



> For property line applications, Voltex is simply installed directly to the retention wall and then the concrete is poured directly against it using a single sided form. Other applications include backfilled concrete foundation walls and cut-and-cover tunnels.


----------



## tgeb (Feb 9, 2006)

ohiohomedoctor said:


> That's what I said............. I think?


No there should be no "outside form".

The products I have mentioned can be attached directly to the surrounding soil, and the new foundation concrete can be poured in place. Leaving no wood products that will later rot or attract insects/termites.


----------



## dcbuilder (Jan 27, 2009)

Tom and Matt- thanks for all of the information. Seems like there are a lot of HDPE membranes made exactly for this application. However, I couldn't find anything on the Grace or Cetco page about putting the membrane up against the soil and then pouring against it. It seems like every application involves putting the membrane up against the retaining wall and then pouring against that. I don't have any retaining walls. Am I missing something? Is there maybe something more rigid than the sheet membrane?


----------



## dcbuilder (Jan 27, 2009)

Do admixtures work at all? That's one idea. Kryton makes one that looks like it would work here.


----------



## tgeb (Feb 9, 2006)

The Kryton product certainly looks like it would work.

I don't quite understand how, if it is water activated, it does not do it's crystal forming process when it dumped into the concrete mix. But if it works it works, it guess. 

The Ceto Voltex can be attached to the soil wall with spikes or sod staples. I would check this method with the Manufacturer, but it should work just fine.

Ceto makes rigid panels 4' sq., but they are shown as exterior applied. You could ask if using them on a blind wall like yours would work, I don't see why it would not.


----------



## Cairncross (Nov 16, 2010)

It seems that maybe you are in a little over your head. Dont you need shoring to avoid digging/undermining the neighbors?Do good research, hire good subs.
You want your waterproofing on the outside (dirt side) of the wall or it is *wrongside* waterproofing.
Blindside Waterproofing
Hire a good water proofer. Select a manufacturer and utilize their details to a tee, make sure the forming system and waterproofing system will integrate well. Dont mix manufacturers products or you will have no warranty.
I use Tremco products. Use super stop in the wall to foundation joint and any vertical joints. Paraseal is a good product to hang on shoring and pour against, utilize their recommended drainage plane and "total drain" type system behind it rather than french drain.


----------



## rbsremodeling (Nov 12, 2007)

Call TGEB and have him come do it for you?


----------



## Nac (Apr 16, 2006)

I agree with everyone else do not leave wood underground. He needs to form the wall with a single sided form only. Place a betonite impregnated fabric against the earth before pouring. That is how we waterproof elevator pits before pouring the concrete. I have a question will you be underpinning the joining properties? The right process is underpinning the a joining properties, waterproof and then builds your wall. Or place shoring sheetpiles and or H piles with lagging waterproof and then build your wall.


----------



## TimNJ (Sep 7, 2005)

Cairncross said:


> It seems that maybe you are in a little over your head. Dont you need shoring to avoid digging/undermining the neighbors?


My thoughts exactly. Do you know what the neighbors foundation condition is in? To form and then pour using their foundation as one side of the "form" can be a recipe for disaster. If you have access with equipment I would put in Superior pre-cast for the foundation or just lay block.

This assumes that you have excavated already. If you haven't excavated you need to exam the neighbors wall to make sure it won't collapse when you dig for your foundation.


----------



## tgeb (Feb 9, 2006)

rbsremodeling said:


> Call TGEB and have him come do it for you?


I was doing a little fishing....I thought he'd take the bait and you went and scared him off.


----------



## dcbuilder (Jan 27, 2009)

*Thanks*

Sorry. I wasn't scared off- been out of town and just saw the new responses. There's no underpinning here- it's an addition to the property that will extend past either of the neighboring houses. I spoke with the guys at the supplier near here and they recommended a similar product to the Voltex that can be laid up against the dirt. I might also just use blocks so I can excavate a few inches further and apply waterproofing with a long roller. I appreciate all the help and I'll let you guys know what we decide.

Thanks
dave


----------



## tgeb (Feb 9, 2006)

I am local, I've done quite a bit of work in NW. DC.

I'd be happy to help you out any way I can.


----------



## mdiego (Jan 31, 2011)

Kryton has two systems that would work in this situation. The first option is to use the *Krystol Internal Membrane (KIM)* admixture directly in the concrete. The second option is to apply the* Krystol T1/Krystol T2* slurry from the inside, once the concrete has cured.

When comparing the admixture to the surface treatment, the KIM admixture is the preferred system as it reduces the the labour required. 

"When combined with water and concrete, Krystol® reacts with un-hydrated cement particles to form millions of needle-like crystals. Over a period of weeks and months, these crystals grow, filling the naturally occurring pores and voids in concrete, and permanently blocking the pathways for water and waterborne contaminants.

Later, if cracks form due to settling or shrinkage, incoming water triggers the crystallization process and additional crystals begin to grow, filling cracks and ensuring that the structure’s waterproofing barrier is maintained and protected.

In addition to filling the pores and capillaries of the concrete matrix with crystals, the KIM® admixture enhances the natural hydration process by intensifying and prolonging the hydration of the cementing materials. This reduces the size and number of capillary pores within the concrete matrix, making it dramatically less porous and improving strength & durability characteristics." -Technical Data Sheet 501 - Krystol Internal Membrane - KIM (K-300, K-301, K-302), Kryton.com​ 
Feel free to contact me ([email protected] | 1-800-267-8280) for more information and for a local distributor.


----------

