I am thinking of buying counsins house which also had an extension added, I was part of the building process ie labouring for him, the jod was done 3 yrs ago really great job but as he got all his family to do their part , all are tradesmen sparks, chippy,brickie and himself plumber done it all so I know job is good I even dug foundations myself, but a friend said I should get cert for later on in case I want to sell house on that it would make it go all the more smoothly but counsin says that he never bothered with a cert because it did not need planning permission as it was a small build I am getting ot for about 20K cheaper than others on the site, counsin is so busy that he cant be bothered and he can be short with if I hassle him ie if you dont want the house then dont buy it, but Q is would it cause a problen later on, thanks