Bug:
Butler doesn't work properly (it attempts to use the planks on the butler when the 'Very good, sir/madam' interface is open, which DOES need to be clicked before he will leave)
It also appeared to not want to pay my butler, but I only tested that once.
Optimization:
If butler banking is selected, you should be sending him to get planks even if you already have a full inventory (unless using the demon butler), because you can make 3-4 larders in the time it takes him to return, effectively doubling your XP rate because you are constantly building vs waiting for him and then building. This also stops him from walking off all the time. Even if not making larders it's best to always have him fetching from the bank.
Lower the sleep time after selecting build on the larder (or other furniture) space
Lower the sleep time after selecting build larder (or other furniture) on the construction interface.
The optimzations would be great, but the butler banking one is vital if you want any real people that like construction to buy your script, and it's the only reason I bought it to be honest, thought it would be functional. Hopefully you can fix that soon?