TC101

Only 3.1m openings so nothing major. Bifolds have a better U value but we don’t want those.

Currently having an extension built & plan to have 3 pane sliding doors. Building reg part L doc states these sliding doors must have a U value of 1.4 W/m2k Very few on the market have this U value, most are around 1.6-1.9 W/m2k....but regs appear to state 1.4 W/m2k U value or C energy rating. I've seen a lot of people have these sliding doors- So do they not comply with regs or they comply as its a C rated door? Any feedback appreciated.

Hello All, Found some great information on here already so decided to sign-up. So will be completing the purchase on a 1980s bungalow in Lincolnshire, which I'm looking to extend and go into the roof. Thanks Toby