However if youre planning to treat more than 5m2 of front garden you must either use a porous surface such as gravel or permeable block paving. Sheds should be a maximum of three metres high unless they have dual pitched roofs in which case they can be up to four metres high. What Is The Maximum Size Shed Permitted Without Planning Permission Garden Junkie Overall height must not exceed 4m dual pitched roof or 3m any other roof Maximum height of 25m if the shed is within 2m of a dwelling boundary. How high can i build a brick shed without planning permission . The permitted development rules have recently been relaxed allowing you to build an extension without planning permission of up to six metres or eight metres if your house is detached. In the case of designated land planning permission will still be required. You do not need planning permission for hedges as such though if a planning condition or a covenant restricts planting for example on open plan estates or where a driver