but one of the examples I found states this which I thought applied since the extra funds were used on a remodel:

A taxpayer can retain the grandfathered $1 million interest limitation,  even if they refinance after 12/15/17. However, the refinanced debt can't exceed the mortgage balance at the time of refinancing, unless the additional amount can be considered acquisition debt  and the total indebtedness falls below $1 million.