Erecting a new building which is less than 4m in total height (i.e. our Stapleton, Kinsham, Walton, Lucton, Byton Low Ridge, Gazebos, Pavilions, Garden Offices and Summerhouses) may not require planning permission if other permitted development criteria is met. Erecting new buildings which are higher than 4m in total height will generally require planning permission. Replacing an existing building may not require planning permission. Useful information can be found here Planning Portal  It is advisable to check with your local authority if you are uncertain.