Why does interior insulation cause cinder block foundations to crack?
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Why does interior insulation cause a freeze/thaw cycle- cinder block foundation?
P Mci
July 5, 2021Last updated: July 6, 2021
I have read in many posts that insulating a cinder block foundation wall from the inside in cold climates is risky as it can cause cracking. This is due to the introduction of the freeze/thaw cycle.
I can't wrap my mind around why this wall would not have already been exposed to this cycle, when uninsulated. Can you help me to understand why it would only experience the freeze/thaw cycle once insulated from the inside, and whether there are any improvements to the process of interior spray foam insulation (crawl space) that would help? Our contractor is suggesting that a portion of the wall (at the bottom) be left uninsulated so that the water can go through this portion.
Thank you!
煤渣砌块基础(或cmu -混凝土砌块单位)在内部隔热时更容易开裂,因为它们不再有内部热量来保持它们的温暖。想想导体和绝缘体之间的区别。混凝土是导体,所以热量很容易穿过它。Here is a quick read that explains it in greater detail -
How to prevent thermal bridges and heat loss
Even if a block wall was not insulated on the exterior, if the interior space inside the wall is heated, then it will have and endless supply of heat to keep it warm. The concrete will absorb heat from the inside and expel it to the exterior. You can probably also notice that the snow is melted close to the wall as well, as the block wall would also be heating the ground. Being uninsulated doesn’t mean it won’t freeze at all as it probably feels frozen to the touch, but without interior insulation the majority of the block would not be frozen, it would only be the very exterior, if that, that would be below zero degrees.
So for a block wall that has been kept warm for its entire life to suddenly have insulation on the interior, it loses that supply of heat, so the entire block (with enough insulation) will probably freeze completely and more closely reflect the exterior temperatures. This does not mean that insulating inside will ‘guarantee’ it will freeze solid and crack, but it is a concern worth considering.
在这种情况下,我们建议在隔热之前先检查砌块墙的状况,以确保它是坚固和笔直的,在非常寒冷的气候下,也许不要使用极端程度的隔热。找到平衡——用绝缘材料节省一些能量,但也可以避免你的墙损坏。不幸的是,找到隔热的“最佳点”并不一定容易,需要考虑的因素包括墙体的年代和结构完整性、砌块的湿度水平,以及你所在地区的低温状况。所以你可能想要和当地有经验和知识的承包商谈谈,以帮助决定前进的道路。