How to check if a wall has been previously knocked through?

Evening Francesca. If you live in terrace houses the layout is usually the same. So if your neighbours have a wall that’s solid in their property then it’s likely been knocked through. If you’re able to drill through the plaster boards I’d assume that there’s something bridging the void as stud work isn’t structural. If I was to support an opening I’d use an RSJ or concrete lintel. Both will have steel in them so a stud finder may pick up the metal. Failing that, the door heights are usually the same so level across from the door frame to the centre of the wall and drill about 100mm above the mark. If it’s solid you’ll probably have a lintel. Hope this helps.

You need to trial hole into the area of ceiling above the existing stud wall at each end and middle of the wall at ceiling level. This is best done just prior to starting the project. Hopefully you will discover a previous lintel or steel beam. It will help your case if the ceiling joists run parallel with the stud wall, giving added strength. Should a lintel or beam not exist, you will need a builder or structural engineer to give advice. Hope this helps.

You can take off the plasterboard from the wall to find out, as long as you have a builder ready to fix it and make good if it isn't. The plasterboard isn't structural only the timber behind is, so you can take as much of this off as you like.

I would speak to building control at your local council to see if anything has been submitted under building regulations for the opening. If it hasn’t you cannot be sure that whatever has been put in place is sufficiently strong for purpose.....it could be that the stud wall is now helping to prevent long term deflection. If nothing has been submitted my advice is to carefully remove plasterboard at the highest point it sounds hollow and then carefully cut out plaster or other wall lining above to expose what has been installed above as support for the opening. Then get a structural engineer to assess before removing the stud timbers below. One thing that builders seem to often forget is that an opening changes uniformly distributed loading to point loads - depending on situation that could be another problem that needs addressing. Ensure building control are aware and when work completed you have a building control completion certificate. You will need to keep that for when you sell. If you had a survey and the surveyor didn’t pick the difference in wall types up you may be able to sue for costs involved if the supporting beam/lintel is inadequate or some other strengthening is required. Likewise you may have recourse against the previous occupants. Hope all goes well for you

The information given by others is very comprehensive. I would just say that you need to be very cautious - to avoid affecting the structural stability of the house. You should have a Building Control certificate for the work completed previously. If you don't then I would consider going for a 'regularisation certificate' - which means that any completed work - and work that you do to remove the wall/partition - is checked by the Building Control department of your local authority - to confirm as compliance with regulations. It's important to have this - for your peace of mind - and to avoid affecting the value of your property.