请有经验的师傅给点建议：
新做的顶楼加建，我们有个French door, 需要加juliette balcony，装修师傅说装在French door的Upvc门框上就可以。结果juliette balcony送到我们发现这东西很重，怀疑装在upvc上面会不会把整个French door给拽下去了，而且不知道这样装能不能过building control。
加balcony 不是要planning permission?
juliette balcony 肯定从墙头里出来的。怎么能装在门框上呢？ 门框就那么点地方。那栏杆螺丝就得好大只的，根本不可能装的进啊。
french door 边上都是木头，应该装在木头上
你的builder装过吗？这不可能是装在门框上的，一定是墙体，还要加固
楼主我替你找到个网站说到装 juliet balcony 的，里面有这么一段：
Vertical loads:
The British standard that relates to loads on buildings (BS6399) and specifically BS6399-1:1996 Amendment 1, clause 10 refers to the subject of vertical loads.
Most balustrades or railings sit ON the structure and directly transfer the vertical loads to the top of the structure and the subject of vertical loads has a small impact on the overall performance of the balustrades or railings. However on Juliette type balconies this can have a tremendous impact and must be taken into account in the design of the fixings and brackets.
The standard refers to a point load of 1.0 kN (appx 100kg) in addition to the horizontal loading. This means the side fixings, or bottom fixing must be capable of supporting this additional load and the balcony solution you choose must be checked
The subject of vertical loads, despite being in the standard for years, seems to have gone under the radar. Recently building control have brought it more under scrutiny.
网站地址在这里：
https://www.balconette.co.uk/juliet-balcony/articles/juliette-balcony-installation
按这个1.0kN+自重的要求，french door本身肯定受不了的吧。
juliette balcony安装受力点在french door 两侧的墙体，固定在两边的墙体。