Price per square metre for an extension in London

Good day to you, Reading your question and understand your predicament asking for a cost per meter square is what I call ''The cowboy's estimate'' and believe me they are a lot such cowboys around especially in London..... Having said that, let me explain why it is not a good idea to cost a job using the m2 method, as this depends on the shape, type, condition, area, size, etc. To give a m2 costing can be applicable, in areas where you have control of one operation in a flat surface, e.g. carpet laying, wall or floor tiles, etc, BUT not in a job, that involves a number of trades. Having masters in PM, in the construction industry, I explain this ''Cowboy Costing'' and let us take a say house extension (let me exaggerate here to make it more understandable), say a 300 m2 area with 3 m high walls. A. House Extension of: 10 meters x 30 meters = 300 m2 B. House Extension of: 3 meters x 100 meters = 300 m2 Both A & B have 300 m2 of area. BUT A = 80 meters wall (running) = 240 m2 (80m x 3m Wall surface). B = 206 meters wall (running) = 618 m2 (206m x 3m Wall surface) As you will see House ''B'' is 2.6 times larger thus more costing, even with the same floor surface area...!! Therefore: A proper professional builder, must proper Cost (QS) every extension individually, so he can be fair to his client and to himself, and not a m2 ''Cowboy Costing''...lol Clients fall always to the same trap of getting the cheapest quote....remember as the saying goes: ''You pay peanuts...you get monkeys''. I hope this was helpful...

Study what the customer wants ie drawing or have a face to face meet with if they have any questions asnswer the truthly and all ways have alternatives solution and if u give a time program try to stay with it's as best and you can