We have two archways that lead into the lounge, one from the
entrance way, the other from the dining room. We want to get rid of the arches and have square entrances instead. How do we go about this. A step by step guide would be much appreciated.

Jane.

 

An arch will probably be constructed of plywood and interior-arch framing to make the arch.
You just have to dismantle the arches, and frame in a header of 2X8s, sandwiching a 1/2" piece of plywood to make up the 3.5" 2X4 wall frame thickness.
Put vertical 2X4s under the ends of the 2X8" header.
Good Luck!
Mike
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