In most cases, loft conversions can be done without requiring planning permissions but you will still need to satisfy building regulations and it is always best to consult with a builder or architect to confirm this.
You shouldn’t need planning permission if:
• The total area of additional space doesn’t exceed 40 cubic metres for terraced houses or 50 cubic metres for detached/semi-detached houses
• The extension does not go beyond the outermost edge of the existing roof sloop at the front of the house
• The extension does not reach higher than the highest part of the existing roof
• Materials are similar in appearance to existing property
• It does not include a veranda, balcony or raised platform
• Side-facing windows are obscured or glazed and 1.7m or more above the floor
• The house is not on designated land such as a national park, heritage site, or conservation area
• Any roof extensions, other than hip-to-gable ones, are as far back as able, at least 20cm from original eaves
• The roof enlargement does not overhang the original outer face of the wall