On average, listings lease in the $50's per square foot per year. The Lafayette submarket is going through a a boost in rates. In the last 3 months, the median rate rose $6 per sqft per year. That's a 12% rise in rent.
Compared to the rest of the East Bay market, the Lafayette region has more expensive rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 17 listings have been made available, which means listings are probably going fast. You'll want to be prepared to make an offer immediately. About 12% of the listings in the Lafayette are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,840 sqft. Most properties in this area are close to 3 stories. Most buildings in this market were built in 1981 and are Class B.