Public Liability Insurance for "diy" job

After getting very disappointed with builders coming up with the most ridiculous excuses to charge a fortune to build the shell of a dormer for my loft conversion I have decided that I am going to employ a couple of experienced guys to do this job for me. Just to illustrate my frustration, a well established loft conversion company quoted me £32k for the whole job including drawings, liaise with building control, dormer, insulation, etc etc.. basically everything included.... whilst these builders want to charge £25k just for the dormer with external finish only, no insulation or anything on the inside.

Since I've decided to manage the project myself I am trying to do it the right way. Structural engineer is about to provide me with drawings so the job will be based on professional calculations.

My concern here is that if I hire a company to do this job for me they would usually have liability insurance. I was wondering if it would be ok for me to have this type of insurance even if I am not on the building trade. Any of you guys ever done that for your diy projects and could recommend an insurer?

Ask in building. £32K for a dormer lofty sounds about right. Though loft conversion 'specialists' are not renowned for their high quality work.

I agree that £32k is not bad but since I can do most of the work myself I was expecting to save at least 30% of that by having someone to do the bits I cannot do such as the dormer shell with flat root. To my surprise the builders out there are not happy with smallish jobs (just don't get how a dormer is a small job)... looks like they do everything or nothing... and if we insist for a quote for just part of the work they just charge ridiculously high just to put me off.

Back in 1981 we took out insurance to cover our DIY build of a house. The one contractor we used ( batten and slating the roof ) did ask to see the insurance. It also covered loss of materials. Useful as one day the babbling brook became a raging torrent flash flood and the costs of replacing some materials that were damaged / lost were all refunded by the insurance. You may find the building inspectors will want to see insurance if they are going on site to inspect.