Warm roof on conservatory

[moveblues]

Hi all
We are thinking of getting a warm roof put in in our existing conservatory- anyone here had experience of this? We aren't getting the whole lean to replaced as it's in good nick, it's just freezing in winter and boiling in summer, and because some clever clogs decided to knock through a wall into kitchen (to make an extension) it's not possible to shelter from the cold or heat! So roof is easiest option
We have found someone who can do it for a reasonable price but I've heard from other companies that there needs to be some kind of approval process when the company hasn't built the base itself. I wondered if anyone might know what this process is called?
Thanks

I haven't any personal experience of this but a friend had a conservatory roof replacement done fairly recently.

The company had the existing structure surveyed first and calculations had to be carried out to ensure the exiting foundations would be able to carry the weight of the replacement roof.
Building regs sign off was also needed.

Her neighbour, on the other hand, had a company come along and whip their old conservatory roof off and put a solid replacement on.
No survey, and no official paperwork at the end of the job.
They paid a lot less than my friend but, I suspect, they may run into problems down the line if they ever decide to sell.