Options for handling a porch beam penetration into a wall cavity
寻找如何最好地处理前廊束渗透到外墙腔中，以在两个2×4的支撑上静置。基本的墙壁结构为Huber的Zip R6.6护套，2×4螺柱和R15吹散的绝缘材料的1.5英寸。位置是5区（中央俄亥俄州）。门廊梁是通过墙壁腔安装的，现在在2×4的末端休息。它的支撑是……目前目前没有隔离的空间，因为它延伸到研究的墙壁上。门廊的另一侧也有类似的条件，但是该光束终止在2'拱腹的旁边，该拱形横向横靠餐厅的周长。
建筑商对减少2×4的光束量的疑虑表示，可以削弱其正确支撑门廊屋顶的能力，并且需要重新设计以通过城市审查。他建议用拱腹的侧面用闭孔喷雾泡沫击中墙壁内梁周围的区域。就研究中的一侧而言，没有能力将横梁隔离……只有侧面。在修剪外面之前，它会帮助任何人在房屋外部隔离吗？在研究中可能还有另一个soff以提供隔离的空间？该地区的木材的R值是什么？类似于窗口？在这一点上，让像这样的愚蠢的东西在腔体中奔跑，否定了R-sheage和Wall腔绝缘的好处，这有点令人沮丧。在此先感谢您的任何建议。
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unfortunately for you, wood's insulation properties across the grain are higher than r-values when the heatflow is in the direction of the grain. Approximate 2.5x less. So wood that would be R 1.4/inch would only be 0.6/inch.
用绝缘材料将其封装确实是有意义的，但是您的第一步应该是首先用胶带开机。
米兰，
Are you planning to install any exterior insulation (rigid foam or mineral wool)? Or do these walls just have R-15 between the studs?
理想情况下，护套将在外部隔热。然后，您将使用sawzall去除光束穿透。然后，您将安装一个新的短梁以支撑门廊屋顶；这款新的短光束将由外部柱子支持。
这是我最喜欢的光束穿透照片。这座建筑归哈佛大学所有。
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You don't penetrate the building enclosure, use hangers to install beams, roof joists or floor decking (if it is a deck above) to a nailer, and the nailer is bolted to a 2x10/2x12/LVL on the back of the sheathing. Also, you could install posts and beams next to the outside wall. Simpson makes you any hanger you need.
感谢到目前为止的回复。Martin ...外护套是Huber的Zip R-6.6产品，该产品具有1英寸的Polyiso键合到标准的拉链护套...因此R-6.6在R-15壁腔外部。要进行更改，需要重新工程以Armando建议使用衣架，然后获得城市工程师的批准（2周？），以进行修改...与之相关的某些时间和成本。其他选择是添加2'Soffit到研究的周长，并击中了整个区域，光束用闭孔喷雾泡沫（拱腹的内部）穿透。计划是将CCSF应用于地下/1楼的边缘托梁和1楼/2层带托梁。这项工作会减轻休息吗？无需工程...只有从平坦到拱腹的天花板的更改。我意识到这不是理想的...看到它是这样设计的。弗雷默说这是典型的构造中西部...惊人。
The R-value of the beam might sound scary high but the transactional area is tiny, so before getting too anxious it might be worth running some numbers. It's been a long time since I've done one of these and then it was in SI units so please correct my methodology if I'm wrong:
通过构建组件传热是钙ulated by means of the U factor, which for a 4" thickness of pine is about 0.3 BTU/hr.SF.°F. If we calculate that out the heat transfer through your beam in central Ohio is about 9,000 BTU per year (0.3 x 0.2 sf x 6,200 HDD x 24 hrs) or 2.5 kWh. Now that is a worst case scenario assuming the exterior of the beam is fully exposed to outside air temperatures - in the real world, encased within trim and the porch structure I think half of that might be a reasonable guess. If your home is heated by a heat pump with a COP of 2 the thermal bridge will be the energy equivalent of running a mid-size Energy Star widescreen TV for just a few minutes a day. Or opening the front door an extra time or two on a January morning because you forgot your wallet.
If you're still worried wrap the exterior of the beam for the first couple of feet with foam board. Furr out the trim for the rest of the beam perimeter to a similar depth with pieces of scrap plywood.
詹姆斯...感谢您将事情置于视角上！同样，每个人的反馈总是受到赞赏。真是一个很棒的论坛！