Which is more expensive per sq foot - a 2 storey or dormer?

Hi,

What's the answer to the above and why?

Thanks.

Dormer
reasons: roof timbers are more expensive than a basic prefabricated truss, insulation is more laborious and you only get one half of the floor area upstairs that you do downstairs. I am sure there are other reasons that an expert builder (which I am not) could give you.

The two storey is generally more expensive because of the inceased area of external walling and chimney height and the larger windows, the pitched roof is generally a void space. The dormer utilises the attic space by using a high pitch on the roof. the roof structure and coverings are more expensive but this is more than off set by the savings in the external walling and windows. The void spaces in the dormer are normally used for the services, the inscreased depth of roof members enable a higher level of insulation to be installed ie. rockwool and thus can provide a better insulated house. The dormer roof can be constructed by a special prefabricated truss or can be cut on site to suit the design.

When you break down the cost and take it as €X per sq. metre or per sq. foot you will find that the 2 storey will give better value