Is there any building regs for window sills?

It sounds as if the installation company has boo booed If the old tiled sills had been left in then yes they would not have needed a 150 mm Sill. ( 85mm stub would be ok ) The problem you will have is that the water will not run off proper. It will soak onto the brickwork,and more than likely YOU WILL GET DAMP

You should be ok, but the windows should have been fitted by a Fensa registered installer, and have issued a certificate.

Hi Kulvir If the tiled sill was removed then they should have put a 150mm sill on. This can be rectified by removing the window and replacing with a 150mm sill. There are two ways that you can ensure compliance with relevant regulations, firstly you may employ a contractor or installer who is registered under the FENSA self-certification scheme.Or a Person registered by BM Trada Certification Limited, the British Standards Institution or CERTASS Limited. A FENSA contractor is approved to carry out the work in accordance with relevant regulations without inspection by the council and will inform FENSA when installation has been completed. Random inspections of completed work are carried out. If your windows were not installed by a FENSA registered contractor then they should have informed the local council building department who then have to inspect the work carried out. Remember when selling your property, surveyors will ask for evidence that replacement glazing installed after April 2002 complies with the new Building Regulations. There are two ways to prove compliance:- A certificate showing that the work has been done by an installer who is registered under the Fenestration Self-Assessment Scheme by Fensa Ltd, or a Person registered by BM Trada Certification Limited, the British Standards Institution or CERTASS Limited. Or a certificate from the local authority saying that the installation has approval under the Building Regulations. If in doubt contact your local council building controls officer who should help you with this problem. Hope this helps Trevor & Mike