有想法把roof做成阁楼，不知道需要不需要向council申请permit?

这样的工程大约需要多少钱？

If you want conver it into a bedroom, the answer is YES.
If it is not, the answer is NO.

The cost of loftroom convertion is vary, depends on your requirement. could be from 6k to 25k.

Check with your council's planning office first just to make sure. Planning regulations have changed quite a lot in recent years and my impression is as long as your house is not in a conservation area it should be no problem and possibly without planning permission.

BTW you can also get some financial support for loft insulation etc. so ask your council for this sort of supports as well, may well save you a few hundreds.

多谢楼上2位，今天找builder看过了，因为我家屋顶高度不够做不成阁楼，一般要2.5m以上高度，如果不破坏外观，可以不需要申请permit，加个天窗就可以开阁楼
安装新楼梯，做阁楼墙面地板和窗户，简单的要求，费用大概3000镑（人工+材料），复杂的可能更贵了。