House Extension

[Plumpie]

Could anyone give me an average price for replacing my garage with a new one and building a bedroom above with pitch roof

[Zacs-Master]

This might help:
https://www.mybuilder.com/pricing-guides/house-extension-costs

[The Builder]

Until you actually have someone on-site to evaluate all the variables, Zacs' link is a pretty good guide.

From here, anything I or others say would be no more than a possibly misleading guess.