No building regs - trying to sell house

G_M

Pasture has identified the key question.
The builder should have built what he was told to build but the architect now has doubts about the foundations - so you may have a case against the builder - but only for not following the Plans. Unless your contract with the builder specifically included getting Building Regs sign-off, then it was not his job.
The architect drew up plans. He may have submitted them to the Planning Dept, or maybe the OP did this and the architects involvement ended there.
The architect may have been further involved overseeing the building work (though I doubt this if the foundations are dodgy!).
If you paid the architect to oversee the entire project then clearly he was negligent and you have a case against him for not involving the Building Regs Dept.
However if his involvement ended before the build phase, then getting Building Regs sign-off was clearly YOUR responsibility.

Jenniflower_2

Thanks all for your advice.

Will let you know how it all works out.

dubsey

Had exactly the same happen on one of our previous properties. Garage converted to a study. Architect drew up and submitted plans, got the planning permission through. Used a friend of the family to do the cnversion, who said leave it all to him and he would get it all done. By the time work had finished we had decided to sell, but it was finished on Christmas eve so it was January before we thought to ask for the certificate for building regs.

Very long story short, he hadn't done it (in his day you didn't need to!!) Employed another builder - stupidly were going to use him in the first place but felt obligated to use family friend - he got the building inspector out and needless to say, our beautiful real wood flooring had to come up and we had to have various vents etc put in. He had also not dug foundations at the front where the garage door had been, he had just started building straight onto the drive, so this had to be dug into and foundations put in. Funny thing was we had sold to someone across the road, so they could see all this going on, luckily he was a builder so knew exactly what and why we were doing things.

It cost us an extra £1200 but it didn't stop us selling, just money and inconvenience while it was re-done.