Doing a remodel on the house (knocking down a interior wall and an exterior and attaching sala for starters) and looking for someone to do the work in the San Sai area. Sure this topic has been broached here numerous times but as things seem to change quickly I thought I'd ask anyway. Thanks for any recommendations.

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A sala is a free standing structure. If it is attached to anything else then it's not a sala. Then it'd be, for example, a ระเบียง. (veranda).

This will help you communicating your requirements when you do find that contractor.