Capillary break and footing types
So I was just talking with my GC about applying a capillary break (something I’ve learned here) on the footing. This is something he hasn’t dealt with before and he posed the question, “will the foundation concrete adhere?” Though I’m as green around the gills as one could be and learning as I go, that sounds like a good question to me. I’m not familiar with all the types of footings there are, but based on our conversations I’m thinking the foundation will be cinder blocks filled with rebar and concrete set over the footings as that is typical in our area. My questions, then, are:
1. Does the style of footing matter?
2.它可以影响与基础的基础上的混凝土粘附吗？
3. Are there any concerns worth being aware of in the design or selection of capillary break product? (I’ve seen the GBA article referenced below, so this question is more in regards to my particular situation)
我也应该提到，如果这向我们的地区和检查员介绍了这一概念，那么肯定会得到一个亲吻方法。The reason I’m even considering the capillary break is because our footings will be located approximately 5′ vertically lower than the road bed in front of our home and though the storm water drainage seems to be okay, I felt like some additional insurance could help improve the longevity of the foundation and footing system. Not to mention tackle any potential rising damp issue early and up front.
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杰森，
除非您倒入脚踏和基础墙体单整体上，除非您最终在混凝土中冷却，除非在混凝土中具有冷凝，其粘附性最小。在过去，两者通常通过形成在脚踏顶部的浅槽连接的浅槽连接。现在钢筋是更常见的方法。
Okay, so then if adhesion is minimal, then this shouldn't be a problem or is what adhesion is there considered critical in any way? And then if using rebar, what approach has seen the most success? Or does the current approach really not need the capillary break? (I'm thinking as long as the foundation is in direct contact with the footing, wicking will always be a factor, but thought I'd ask in case there's additional dynamics at play that make it less feasible).
杰森，
我只是没有足够的有用的经验或知识。希望别人可以聊天。现在毛细血管休息被局限于一小部分高性能的建设者。这不是以任何方式贬低它们，但这意味着他们是我们大多数人的利基技术并不熟悉。
谢谢马尔科姆。我的gc是一个很好的，我知道当他没有意识到这有一些东西。我认为我们该地区的标准并不典型。在看所有产品并实现不同类型的基础/基础之后，我可以看到。
对于有关不完美毛细血管破裂的有趣实验，堆叠（上底）一块干纸巾，一块带有微小孔的塑料薄膜，然后是一块湿的纸巾。将它们按住几分钟。干纸变得非常湿。
Not sure what to make of it. Thick sheets of EPDM (vs thinner, more delicate alternatives) are better for capillary breaks? Or concrete admixtures? That full gravel surround (under slab, under footings, against walls) is best for dry concrete? Then there are those who claim that wet concrete doesn't matter (while also claiming that a capillary break is important). I see almost no data pertaining to good, modern concrete and the various techniques.
Lol... definitely more questions than answers...
Also, I'm a EE by trade, but work with some CE's and they'll tell you that wet concrete doesn't matter. However, that's from a structural perspective. From a home construction standpoint, this means introduction of moisture into your basement/crawlspace and worse case into your home (rising damp). If the latter occurs, the fix is expensive and involves someone drilling into your foundation and injecting a sealant that will be absorbed by the concrete and setup up to retard the movement. I figure if I'm already aware that moisture will need addressing, might as well get those low-hanging improvements. A few hundred on a barrier now might save a headache's worth of problems later.
Hey Jason.
As Malcolm said, the joint between a footing and concrete foundation walls is typically not a bonded concrete joint. As with your concrete block wall, it's the rebar that will mechanically connect the two. There are membranes that can be used as capillary breaks, but I know some builders find them difficult to install around rebar. Mike Guertin used a fluid applied product--ProtectoWrap’s LWM200--on the FHB ProHome:
https://www.finehomebuilding.com/2016/07/04/capillary-break-coating
谢谢你的链接和产品信息Brian。我已经复制了这两种和GBA文章，以及我的GC和当地检查员。我去了保护网网站，在申请前没有看到混凝土的干燥时间。我会继续看，可以联系它们。你碰巧知道吗？我知道在申请前一个月有一些产品，我不希望这对我们的GC来说是一个巨大的负担，也不希望我们的日程安排，这样他再也不会这样做了。
Update: Senior moment... per the article I linked above, it can be applied immediately.
Just a thought on the products listed by Martin - If asphalt damp-proofing is going to be used to protect the concrete from water intrusion from the outside, can be applied to uncured concrete, and backfilled quickly, it might be the good choice to use as a capillary break too.
Excellent point. And any excess could be used on the sides.
For what it's worth, I'd also pay attention to the footing drain. Most of us detail it so that the drain channel and material is *below* the top of the footing. This gives water an easier path to continue along than through the footing. However, most contractors shortcut and put the drain level above the top of the footing to save time and money, which just means that the lowest level that the water can sink to is just barely above the cold joint between CMU and footing. They do this because to get the drain below the top of the footing, you either have to "over-excavate" by about a foot and then build formwork in the footing trench, or you have to excavate as normal for a footing, then after it's poured, come back and dig out the foot or so to the outside to lay the drain.
看到的细节:
https://basc.pnnl.gov/resource-guides/footing-drain-pipe.
Jason C,
在似乎挑剔的风险，您链接到仍然易受攻击的细节，因为板块底部直接在脚踏上休息。最佳实践是有几英寸的填充分离两者。这两者都提供了一种用于在板下移动的水分的路径，并且由于填充的差动沉降而使平板不太可能在边缘处破裂。
Absolutely, a very reasonable observation and solution. I linked that detail simply for the drain location relative to the footing.
杰森，
I've learned from experience that posting a drawing here to illustrate one thing often has people accepting an unrelated part of it as good practice.
I've found a similar problem with design drawings. Clients will often reject an option because of the colour I used on the illustration. "That one is out. I hate yellow!"
好了,到目前为止,检查员没有说不,但是n't said yes. He has expressed concern that putting another layer between the foundation and the footing would affect the frictional forces. I've sent information (like the Fine Homebuilding article) on it. But so far, no one feels convinced it's the route to go. My GC is already trying to figure other alternatives to pulling water away. And what makes me personally least comfortable is that after talking with some of the representatives for the recommended products (like Protecto Wrap or Epro), it took quite a bit of conversation for them to even understand the application. Although in the end, they said it should work, they definitely acted as though this is not the norm and not in their cross-hairs. Maybe this just hasn't caught on? I'm not sure at this point what else I could do other than show them studies where this has been tested and unfortunately I don't have the feeling that has ever been done.
I have some misgivings as to whether the absence of a capillary break is a problem in most circumstances.
英国家庭中的“潮湿”来自建造连续砌体或混凝土结构的实践，从屋顶延伸到屋顶，可理解地将水分粘在家中的条件下。
The situation in North American stick-frame construction seems to me to be a lot different. Can someone link to the original research that showed this is a significant problem here? I think it came from BSC research, but all I can find is their concern that the salts in soil may cause masonry to deteriorate prematurely.
我能想到的最大问题是，任何从基础上邪恶到有效封装的边缘托梁（假设良好空气密封）的水分可能会导致轮辋托梁随着时间的推移而恶化。
Bill
我们用过两种共同的砌体封口机;似乎有可能帮助我们采取其他措施，但地区最终很干燥。
Might I recommend the Dorken line of products. Might be worth your time to look and see what they offer?
https://www.dorken.com/en/our-products/resiential-products/basement/foundation