From here at Design for Me, during Spring 2017, we asked

Most builders will give a free quote for the works, but the more information and detailed drawings you can provide them with, the more accurate their cost estimates will. Building regs would apply, of course. Hopefully it won’t be needed but it is best to be prepared as, working with an existing building in particular, can throw up some unexpected issues that will need to be resolved. From here at Design for Me, during Spring 2017, we asked our community of architects and design professionals; “How much does an cost of building an extension cost in London”? Hi there, How much roughly should I budget to have a 30sqm extension built on my home? Your extension could be an open kitchen / living space. However, if you are in a hurry, you can instruct the Building Regs while awaiting the council approval. A 17m² extension above a typical attached single garage would cost £900 to £1,500 per m². Ask your architect to help you arrive at the kitchen extension cost, once the extension plans have been submitted. You can see more on financing your extension here. If you are looking for a high end finish this will increase the costs per m², and if your extension includes a kitchen or bathroom these will be extra. A budget kitchen can cost £5000 if you are thrifty, but our research suggests a figure of £8000 is more common. If you are looking for kitchen extension ideas, Extension Architecture is a dealer for top quality, bespoke German kitchens. The cost of plans for a single storey extension will obviously be less than that for a double-storey extension. Want to build an extension for between £50,000 and £90,000? All this can mean that the overall costs can be up to £5000 even before work on the extension begins. All you need to do is tell us a bit about your extension project and we’ll help you find the right architect or architectural designer for free! It is possible you may get cheaper quotes, but the builder may not include the cost of everything, or they might underquote the cost of labour. Prices will vary depending on the work you carry out, but as a guide, plan for between £1,200 to £3,000 per m² and upwards for building work; £17 to £200 per m² for a new kitchen. Per metre pricing is a technique used by salespeople and some builders to estimate the cost of a project by measuring the floor space and multiplying it by a figure. A traditional-style house extension option, an orangery is designed to be in keeping with a period house and measuring 30m², would cost between £1,250 and £1,450 per m² depending on location.