答复

1. Expert Member
   Dana Dorsett|2015年2月25日05:59 PM|#1

   There is no risk to insulating on top of the slab, especially in a building that is now being heated.

   The slab is at greatest risk of frost-heaving when the barn was not heated, and the direction of heat loss is from the ground upward, rather than from the building downward. Frost heaves propogate in the direction of heat loss. With a heated building above it, even that modest heat loss is going to

   A: keep the soil directly under the slab above freezing, and

   B: the direction of the heat loss is from the slab downward rather than conversely.

   The story with foundation walls is similar.

   You absolutely DO want to install insulation under your leveling over-slab, along with a ground vapor retarder. Without it the slab can run cooler than the outdoor dew point in summer, increasing the mold potential for any rugs or boxes resting on that cool slab. With insulation under it the slab tracks the temperature of the conditioned space within a few degrees.

   In a zone 5 location R5 would be sufficient from just a mold-hazard point of view, but ~R8 would still be financially rational using modest assumptions about the cost of money and future energy costs. With 2" of Type-II EPS (R8.4) that would run you about 75-80 cents per square foot, which isn't much different in cost from a mere R5 using 1" XPS. (And over the next 50 years that R5 XPS performance will fall to about R4.2, whereas the long term performance of EPS is pretty stable.)

2. GBA Editor
   马丁·霍洛拉|2015年2月26日07:13 AM|#2

   院长，
   有几种方法可以看这个问题。

   1.如果谷仓板块在几十年内幸存下来而不破裂或冒险，不要担心。毕竟，我假设当它用作谷仓时，谷仓没有加热。它似乎在寒冷的天气里幸存下来。

   2.在过去，谷仓含有设备，干草，也许是一些动物。当旧时光户外为-18°F时，谷仓的内部可能已为0°F或-10°F。所以板块下的土壤可能会冻结。然而，现在，您的新家将被加热。在板坯上方的热空气而不是板上的冷空气，因此板块下的土壤不太可能冻结。

   3.您应该在板坯的周边安装垂直绝缘。这将有助于将土壤保持比以往任何时候都更温暖。如果需要，您还可以将水平的“翼绝缘”作为围绕您的建筑物周边的围裙安装 - 或许6英寸或12英寸以下，从大楼延伸4英尺。

   5.想象一款由下面的混凝土板组成的三明治，下面是水平刚性泡沫的刚性泡沫。现在将其与第二个三明治进行比较，该三明治由混凝土板组成，上方具有刚性泡沫的水平层。对于平板下的土壤，这两个三明治表现得相同。无论泡沫是否在板上或下方，两个三明治的R值都相同。

3. 
   Dean McCracken|Feb 26, 2015 07:46pm|#3

   我将向我的建筑师传达的优秀概念。优秀，因为我已经想到了其中一些（拍了拍自己）。

   Martin, I cannot in good faith say that the slab has not cracked. The center "aisle" of the barn has several significant cracks, though I can't say I think any of them show signs of heaving... more like settling due to insufficient substrate support. The remainder of the building is carpeted at this point so I'm not able to comment on how the perimeter of the slab has fared. This building went frrom horse barn, to devided residence and business offices (what barn has 24 T1 data lines coming into it!?) I think we are in a good position to say the various sections have been both heated and cold.

   Dana, you used the term "leveling over-slab" which is pretty much what I anticipated. However, only the center third (longitudinally) of the building requires leveling. Is there a viable alternative to a full depth slab-over? Perhaps level the center section then put a layer of insulation throughout, then sub-floor? I estimate a full over-slab would run me about $4000, which I'd gladly use elsewhere! I based my estimate on a 4" depth.

4. 
   Dean McCracken|2015年2月27日08:33 PM|#4

   所以我与我们的建筑师分享了你的想法，这是他的回应。您是否通过粗线条分享了我的伴随的担忧？这个大会会降低凝结风险吗？看看你的想法：

   “鉴于我们所发现的一切，我建议一个可能的解决方案：1）将我提到的混凝土封口剂喷涂; 2）摇篮平面处理的2x4毛刺条@ 16”或24“OC与当前中心走廊中的雪松垫片建立它水平的区域; 3）在毛刺条之间加入1 1/2“XPS泡沫（约R7.5）;4）安装5/8“或3/4”胶合板地板护套（约R0.77）;5）安装你想要的楼层的底层。“

5. GBA Editor
   马丁·霍洛拉|2015年2月28日06:17 AM|#5

   院长，
   1. Your concrete sealer may work; I haven't used such a sealer. But, sealer or no, you still need to install a layer of 6-mil polyethylene above your slab before insulating.

   2.您所提出的方法将有效，但是通过毛刺条将热桥接。它会更好（虽然可能不会更便宜），用平整化合物或薄湿混凝土或灌浆的薄湿混合，具有小直径骨料。一旦液位表面，就可以在没有任何毛刺条的情况下安装平板板上的连续刚性泡沫层。