Is an Architect absolutely required for a single family rehab

[Brandon Arce]

I have jumped in the water, bid on a property, and contract is in progress.  The biggest obstacle so far has been obtaining repair estimates.  I have had a few contractors over, and they have told me that they won't be able to give me an estimate until they see the drawings from an architect.  I feel this comes about when I mention I want to bring down some walls to open up the space. Is that absolutely necessary? what if I don't change the layout of the property?