S.J. Development is made up of family members and trusted, expert trades people. We are dedicated to building loft conversions and home extensions to our own exacting standards. When you invest in your home by choosing to extend, you want to be sure that you will be increasing, rather than undermining, the value. S.J. Developments is a family run building company specialising in loft conversions and domestic extensions. With over 20 years of experience in the industry, we pride ourselves on producing work of the highest quality. As well as designing and constructing the extensions, we provide all the associated building services, from joiners and plasters to plumbers and electricians.