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.
New Tredegar
New Tredegar is a former mining community and community in the Rhymney Valley, Caerphilly area borough, Wales, within the historical borders of Monmouthshire. New Tredegar is now home to 'The Winding House', a county gallery which opened up in 2008. It is regulated by CCBC Museums solution and the Friends of the Winding House community group. The area is abundant in the mining heritage of the South Wales mining industry. The area is sustained by 2 primary schools; White Rose Primary school and also Phillipstown Primary school. The location also has a number of religious buildings including; Saint Dingat's Church as well as the Presbyterian Church of Wales. Together with various other parts of Rhymney, New Tredegar was just one of the last areas within Monmouthshire to preserve the Welsh Language, with indigenous audio speakers using the language in shops as well as banks into the 1970s. Welsh-only monoliths in the local cemetery demonstrate the stamina of the language in your area in the very first quarter of the 20th century.