Planning Permission Tips UK - Rights of Light to Adjoining Neighbours Windows - What You Should KnowTip! It would be a mistake to assume that all the windows in your home are the same size, even if they look exactly alike. The fact is that window sizes can vary from room to room, or even within the same room. Rights of light - What a minefield this topic is when developing or extending a property. This is potentially one of the most subjective Planning issues their is. Most Planning Departments will have guidance but I guarantee it will be specific in parts & definitely woolly or non specific in other areas leaving the subject wide open to interpretation. One of the most common areas for debate is with regard to side windows on neighbouring properties. The general rule of thumb is whether or not the neighbours side window is a principal or secondary window. If if is the only principal window for a neighbours room then the chances are the Planners will pay great attention to your development or extension. They will want to be satisfied that the window is not interrupted from skylight by your building project. Secondary side windows on the other hand to habitable rooms or windows to non habitable rooms are far less contentious & are often ignored by Planning Departments in their impact assessments. However, this is only a rule of thumb & surprises do sometimes occur. These surprises often arise from neighbour induced objections where the Planning Officer is forced to stick out his neck & make a case to support your scheme against that of the neighbours vitriol - you don't see many headless Planning Officers these days do you - you get my point.
What about the scientific proving of light issues I hear you ask to override the Planning Officers negative opinion? Well yes their is guidance from the BRE called 'Site layout planning for daylight & sunlight - A guide to good practice' by PJ Littlefair. However, this £55 document is seriously complicated should the need arise for proving diagrams using Waldram diagrams. The novice will never understand it & the same applies to most Planning & Appeal Officers so you are advised to avoid the scientific approach like the plague. Even the official chapters of the guide clearly state that...."The advice given here is not mandatory & this document should not be seen as an instrument of Planning Policy" However, the guidance on whether or not your building works actually obstruct the light to the neighbours window is actually very useful in proving to the Planners that you DO NOT need to prove by calculation any loss of light. You would be surprised when you do work out this 25 degree vertical reference line of light just how close some new buildings can actually go to the troublesome windows. Therefore, if your getting resistance to you scheme on light issues, go get this BRE Guide first from any good stationers or the BRE direct - it could be the best £55 you have spent in helping to get your scheme recommended for approval. Tip! When a new home is being built,the windows are nailed to the wood studs that make up the house frame.In order to accomplish this, new construction windows have a fin around all four sides of the frame that rests against the outside of the stud and nails are driven into the studs through the nailing fin. In most rights of light issues, the pragmatic & practical assessment approach is often more productive than the scientific process unless you are dealing with a freshly qualified Development Control Officer who can often recall the theory of these Waldram Diagrams with distinct ease, I would stick to the commonly understood simplistic approach of 'fact & Degree' in your negotiations. From a legal stand point, most solicitors will advise you of the 20 year rule where a neighbour has a prescriptive right to light if they have enjoyed 'uninterrupted' light for a continuous 20 year period. Now solicitors love the BRE scientific approach as it is a potential fee earning category for them in defending upset neighbours or for fighting a scheme through the appeal process for a developer. Unless you have a large pocket for to absorb abortive fees stay well clear of these sharks & only use them as a last resort. The conclusion to side windows & right of light is this - Most neighbours that have a side window facing your development or extension will complain to the Planning Officer. Just because you chat over the fence every weekend when hanging out the washing will not automatically preclude that neighbour from complaining during the consultation process. Therefore completing a risk assessment of these windows first is vital . If you discover a neighbours principal window to a habitable room on the side of the property adjacent your own building works DO NOT IGNORE IT. Adjust the design of the new building to take this window into account. There are other clever tactics & arguments you can employ that could allow closer development if there is no other option for your scheme. Tip! Greenhouse windows that come piecemeal are for those who wish to customize or build their own greenhouse, or for those who need to replace an individual window that has broken or otherwise ceased to perform. Be sure that the manufacturer specifications match the measurements of the fittings in which you will have the windows installed. Our 'Maximum Build Planning Guide' explains further side window issues in more detail & sets out various risk assessment procedures & tactics that you can incorporate within your scheme when dealing with rights of light issues. I would not advocate submitting any Planning scheme until you have assessed these affecting side windows & prepared your defence - you have been warned. Our 'Maximum Build Planning Guide' explains further the tactics involved when developing land or a site for residential use & how to give yourself the best chance of being granted planning permission. http://www.planning-approval.co.uk | 
