Capillary break sprayed on to footer
We are pouring footers next week and have to make a decision on how to provide a capillary break between footer and foundation wall. Specs in our contract builder call for a liquid applied product to be used, with a $250 allowance for that. The idea was to apply it before drilling in the rebar, then to patch as necessary after rebar is in place.
Now my builder is suggesting that we could instead have the waterproofing contractor spray Tremco Tuff n Dri on the footer after the rebar is in place. He would do this for $250, so it’s within budget.
Any thoughts on using this product for capillary break? It seems like an “off-label” use and I’m just wondering if there might be a reason I’ve never heard of it being used for this purpose. Tuff n Dri dries to just 40 mil thick. Is this perhaps too thin for this application?
Please help if you can, we’re up against this decision and I don’t want to screw up this critical detail.
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Replies
Tremco has good product solutions for basements and footers, I specify them often. You should be glad your builder is planning on using a capillary break on the footer, most don't. Whichever product he decides to use it should be applied per manufacturers instruction, which you can download for free.
William,
I wrote an article on the topic. Here is the link: Capillary Breaks Above Footings.
According to my memory, I spoke to technical experts at Tremco as part of my research for that article. As I reported, the Tremco product you want is called Tremco TREMproof 250GC.
Yes, Martin, read that article and that's why we specified this with our builder. There are two reasons why we'd prefer to use sprayed on Tuff n Dri here as opposed to the Tremproof 250GC.
One is logistical - the nearest supplier of Tremco sealants is a 4 hour drive from here, but we have a local guy who can spray on the Tuff n Dri.
The other reason I got just now from tech support at Tremco sealants - we'd have to be extremely neat applying the TremProof 250GC (modified polyurethane) - it's incompatible with the Tuff n Dri (polymer-enhanced asphalt.)
The Tremco sealant technical rep wouldn't make any recommendations about using Tuff n Dri for this application because that's a quite separate division of the company (Tremco Barrier Solutions). I am waiting to hear back from the tech rep from that division.
But, if anyone might be willing to go out on a limb and answer this question ... how could a polymer-enhanced aspahaltic membrane not work as a capillary break between footer and foundation wall? Seems like a no brainer but am I missing something?
A related question...is there any actual bond between the footing and the foundation wall concrete other than the rebar? In other words, does the capillary break interfere with any bond between footing and wall (concrete to copncrete)?
Kevin,
Unless you pour your footing and walls as a monolithic pour (as some builders still do on the West Coast) there is no appreciable bond between concrete in the two, whether you use rebar or a keyway. So the presence of a capillary break doesn't make any difference.
Thanks. I have always wondered that.
Hi, Trying to figure out if we can use a polymer enhanced asphalt coating as a capillary break? Would use the same sprayed on product they'd spray on the foundation wall. Think it is similar to Tuff N Dri...Ultrashield WB - https://www.gmxco.com/products/waterproofing-membranes.html Thanks!
Alec,
I have no direct experience with that product -- but I'm guessing it would work, subject to the usual questions (mentioned in my article) about (a) how long you have to wait after the footing has been poured before you can apply the coating, and (b) how long you have to wait after the coating has been applied before you can set the wall forms.
It would never hurt to contact the manufacturer to get answers to these questions.
Thanks!
I used a product called Zypex (https://xypex.com/products/coating-products/concentrate) to seal my footer before stacking and pouring my ICF walls. Can't speak to its effectiveness as we haven't even backfilled the foundation walls yet.
David,
In Martin's blog on capillary breaks I suggested Zypex. Martin contacted the company and they wouldn't confirm it should be used for that purpose. I have a bit of trouble understanding why not, but technically it isn't one of their approved uses.
I have used the bulk additive directly in the ready-mix. The additive is supposed to be able to block hairline cracks up to 1/32" in walls subject to external bulk water. I believe this version is better known among builders putting foundations in near lakes. The surface applied version is promoted to parking garage owners or commercial facilities with large truck aprons, I think. The idea is to help keep surface water and pollutants from being carried down into the concrete where is might create havoc with the rebar over time. I believe the crystal material that fills in the cracks is formed when bulk water is available. Not sure if it goes away under dry conditions.
The company may not want to say it is an approved use due to some confounding factors that even your polyurethane or asphalt won't overcome. Improper placement of the footing drains is one of the most common things I have seen. Some builders insist that you accept their nesting the pipe in the corner formed by the wall and footing. As many here on the forum have noted, this is flat out wrong. This guarantees bulk water will saturate the joint and the bottom of the wall eventually. Stepped wall footings present a similar problem with the transition points where, despite the pipe and aggregate, little wet pie corners can be created. Well detailed coating of the wall down and over the footing go a long way toward preventing big problems, but I always plan for any coating to fail some time in the future.
For what it is worth, I used Xypex additive mixed into all my concrete; footings and walls. This method might function rather differently than the surface applied version. In my case, the footings are all on bedrock subject to spring melt water transport due to the fractured layers. Despite extensive and carefully placed footing drains I do see water build up inside the perimeter of the foundation through my peep-pipe. I opted to mix in the Xypex in all loads to prevent the footings and the stepped wall parts below the slab pour from being able to transport moisture upward. It has worked beautifully and I have the driest basement ever. Nice for my tools and lumber. It was a bit rough on the pocket book though.
I would think hard on ground water conditions, the quality and longevity of any wall coatings, careful sealing of the transition of wall to footing points, and close attention to downspouts and surface grading. If the footings are sitting in water it may be hard to get the wall to stay out of trouble.
Hi,
I have been advised to spray in Foxfire as the capillary break on top of my footings. Has anyone used this product for this application before? Thoughts? Thanks
Andrea
Andrea,
I found a company online that sells Foxfire brand products. Here is the link:
http://www.foxfireusa.net/
Which product are you intending to use? I don't see any mention on the web site of a product recommended for use as a capillary break.
Hi Martin,
Thanks for your fast response. The product is Foxfire P1007 and can be found under waterproofing systems at Watertitesales.com.
Andrea
I'm using the same product I'm using on the exterior of the foundation - Rub-r-wall Plus. Finally found someone who will actually spray it onto the footing. I can't believe how many industry pros have never even heard of doing this, and argue over and over that it's not needed. I mean... if they embraced it, they could have a new market and more money coming in!
I actually contacted the manufacturer of Rub r wall about this and they didn't want to support it.... but I don't see why it wouldn't work.