Hi, I'm new to this so be gentle. I'm having a garage conversion which includes a new doorway in to the hallway from the side of the garage and I'm concerned the builders aren't using a sufficiently strong lintel. I've paid for an 'all-in' service so I haven't really been part of any of the engineering/surveying conversations; we basically just said what we wanted and how we want the finished thing to look. Its a typical two story, 3 bedroom, brick and concrete block built house with tiled roof. Its a 'link-detached' house (only the garage on the ground floor connects to the neighbours house). The new doorway is going to be for a 800mm door so the opening they are cutting will only be about 900mm Anyway, I was having a nosy around yesterday and noticed they had taken delivery of a lintel that looked (to me - a layman) as being a bit small for the job. It still had the stickers on it and it is definitely this 'model' https://www.birtleylintels.co.uk/product/sb100/ and in the 700mm to 1500mm category. Now I'm no engineer, although my physics and maths has always been okay, but looking at the values of that lintel could it really take the weight of the upstairs,the roof above it and everything that goes with it? Thanks guys.