I have wall separating my kitchen and dining room, that I would like to remove. I'm pretty sure it's not load bearing, however the studs on my raised ceilings do sit on the top of it. In removing the wall, how big of a header do I have to install?
If the wall is not load bearing, you need only a small header. If the wall is load bearing, you need to size the header based on the span and the load above the header. In order to size the header, you need a carefully prepared, scaled diagram showing all of the load the header will need to pick up, which may require crawling into the attic to verify how much load is transmitted to the wall below.