En-suite without building regs approval

[1st time flat owner]

We suspect that one of the toilets (en-suite) in our flat has been built without building regulations approval about 8 years ago (by previous owners). Our freeholder now understandably requires us to check the works have been done to a good and safe standard, and we’re having to apply for a retrospective regularisation from our local building control.

Regarding the plumbing and ventilation, are intrusive inspections often required for this? We suspect new plumbing is under our bedroom floor (hot/water pipes, waste water pipe etc). Would the surveyor need to pull up floorboards etc to check everything?

Thanks for all your help!

 

[frutbunn]

Check with your local authority to see if they received a B Reg app first. If not you can apply for a Regularisation certificate. You must satisfy building control it complies with the B Regs applicable at the time the work was carried out, this may involve opening up and/or remedial work.
The way I deal with them is to carry out an initial inspection, depending on the site specific work I may then require some of the work to be uncovered. Its unlikely I would insist on exposing the waste pipes, water pipes are not considered by B Regs.
Strictly speaking you should provide plans of the work prior to it being carried out, as it is now along with any remedial works. I have never insisted on this, nor have any authorities I have dealt with on the other side of the fence, but best to just check with them.