Floor and tile contractor payment question

[Lisa Pigno]

I am building a home and have a flooring and tile contractor, I have paid for all the materials up from 32k , tile people hired by floor tile company have worked 4 days and have about another week to complete job, contractor ( flooring company)is requesting we pay them 1/2 of the labor now and rest when job complete , we do not feel comfortable doing this because job is so short, we think only fair to pay them full price off labor when job complete, does this sound normal