基礎工事に最適な季節は？

This time, we'll explain about foundations. We're often asked by customers, "When is the best time to start building a house?" Conversely, "When should we avoid building a house?" This depends on the region. Our company is located in Ota City, Gunma Prefecture, and speaking specifically about Ota City, it seems that there's no particular harm in starting at any time. From a construction perspective, if I had to say, it would be the rainy season. Doing concrete work during the rainy season is quite troublesome. The amount of work required for curing, such as covering the concrete with tarpaulins to protect it from rain, is enormous, so we prefer not to pour concrete during the rainy season if possible. From our perspective, it's easier and better to build the foundation before the rainy season or after the rainy season ends. The temperature in Karuizawa, right next to where I live, is completely different from Ota City in Gunma Prefecture. The minimum winter temperature can drop below -10°C. This causes freezing, meaning the mud freezes, making digging impossible, and concrete doesn't harden easily. Therefore, in Karuizawa, concrete work isn't done in January or February; the foundation is done in December. In Hokkaido, daytime temperatures can drop to -20°C. Doing foundation work there would be extremely difficult, so it really depends on the location. That being said, there are points to be careful about when doing foundation work in cold weather. That is, increasing the strength of the foundation concrete. This is often called temperature compensation. Concrete is made by mixing cement, crushed stone, and water, and then hardening it by using the heat of the cement to evaporate the water. When it's cold, even if you pour concrete, the heat doesn't rise easily, and the water doesn't evaporate. If the water doesn't evaporate and you're faced with a very cold morning, the water inside will freeze, and in some cases, cracks will form in the concrete. These are cracks caused by freezing. When cracks form, the concrete loses its strength. To prevent this, we sometimes increase the amount of concrete through a process called temperature correction. There's a standard for this: when the outside temperature drops to single digits, we apply temperature correction to increase the concrete's strength. Increasing the concrete's strength essentially means increasing the amount of cement. Normally, the concrete strength we use is 24 kg in warmer seasons. In colder seasons, we add 6 kg, bringing the total to 30 kg. This allows the concrete to heat up even in cold weather, making it less likely to freeze. The difficult part is that it's not a law that mandates this. It's merely a guideline, suggesting that it's better to do it this way, so it won't be a legal violation or something that will be questioned during building permit inspections. Rather, it depends on the individual housing company's approach. Some companies use concrete with a strength of 21 kg, while in colder regions, they might use 27 kg from the start. It varies quite a bit. There's no single correct answer because the hardening properties of concrete also vary by region, but generally speaking, it's often said that concrete with a strength of around 24 kg has a lifespan of about 60 years. When building a house, especially for younger people, they might live in it for 50 years or so, so it's probably best to use concrete with a standard strength of 24 kg. Furthermore, when pouring concrete during the cold winter months, or when pouring concrete in cold regions in general, it's best to use 27kg of concrete from the start, or adjust the temperature to 30kg. It's a good idea to ask your chosen home builder about this. Also, one more thing: concrete won't harden if it's too hot. Even when pouring concrete in the scorching heat of mid-summer, it won't harden properly without temperature adjustment. As the climate continues to change, it's especially important to consider the strength of the foundation when planning. -------------------- We'll share the correct knowledge about home building that even sales representatives at home builders don't know. More detailed (and even more candid) content is available in our email newsletter. Delivered every Monday, Wednesday, and Friday. Registration only requires your email address. Register for the email newsletter here. http://www.kosodate-sekkei.co.jp/maga... Subscribe to our channel here: http://bit.ly/kosodate__youtube Our website is here: http://www.kosodate-sekkei.co.jp Online individual consultations are available here: https://www.kosodate-sekkei.co.jp/sta... #ChildcareDesign #Foundation #Concrete #GunmaPrefecture #TakasakiCity #CustomBuiltHomes