It depends on the size and type of extension. Small porches or flat roof extensions are very reasonably priced. More substantial two storey extensions can be expensive. In general, the price is roughly proportional to the amount of space you add to your home.
Corwen
Corwen is a town, community and also electoral ward in the region of Denbighshire in Wales; it was previously part of the county of Merioneth. Corwen bases on the banks of the River Dee below the Berwyn mountains. The community is situated 10 miles (16 kilometres) west of Llangollen as well as 13 miles (21 kilometres) south of Ruthin. At the 2001 Census, Corwen had a population of 2,398, decreasing to 2,325 at the 2011 census. The community consists of the towns of Carrog and Glyndyfrdwy. The built-up area according to Nomis was 477 however does not consist of the estate of Clawdd Poncen. Consisting Of Clawdd Poncen the overall is 777. Located in the hills of north Wales, the primary economy of Corwen is based in and around farming. The town's main employer is regional trailer supplier Ifor Williams Trailers, begun by a farmer aiming to carry lamb to the neighborhood market.