Are you planning to add another floor to the existing property? Do you have the planning permission for the same? At the same time, if you have siblings, it is important that both of you are on the same page. Since, both of you have equal rights on the property, you cannot decide on adding another floor without consulting your sibling. If the property were only in your name then things would have been different. But as per the law of property, both the siblings have equal rights on your parent’s property. If you thought that there was hardly any issue then you need to think again. Both your sibling and the concerned authority should agree with your plan so that you can go ahead and execute it.
Have a clear discussion with your sibling so that he cannot raise any issue later on. At the same time, you need to submit the planning applications Berkshire for approval. Once the application is approved you can go ahead with the construction of the second floor to the existing property.
To know more about the planning applications Windsor, you should get in touch with an architectural design firm. They have the required information. They will help you in filling up the form and in its submission. Share the relevant documents that you need to submit with the applications to the architectural design firm. Let them look into the matter and handle it. Do not try to do this on your own when you have got experts to look into the matter.