Charly

Thanks @Declan52 I'll chop that away tomorrow. The joists run across that wall and the wall continues up into the first floor and again in the attic the joints rest/overlap on that wall. Cheers

Thanks for all the help, @Russell griffiths the house is victorian, I assumed the black was some kind of older plaster, it appears on other walls just in areas like it's been used to patch? @Declan52 I've drilled into it in a couple of places around 40mm and just seems to be solid concrete? Pics below - do you reckon ok to remove curved arch bits??? Thanks

Thank you, I had already waked it with a hammer and seems pretty solid I'll put a drill through it tomorrow... thanks again

Hello! I want to square-off the archway as shown in the picture below, marked-up in red. I've chopped away some of the artex to reveal some concrete which has the original black plaster around it I believe. By looking at the photos, do you think there is a lintel or some sort of support to hold up the walls above? Can I go ahead and square the arch off? Is there a way I can find out if there is a lintel in there? - The wall with the arch is a supporting wall I believe as has foundations below it, solid walls above it and has joists resting on it in the attic. Any help would be massively appreciated. Many thanks - Charley