@Tom541
This just happened to me. Unexpected construction outside on the street. I've had dozens of guests who had no problem with it and then this one shows up and wants a refund because of the noise. Come to find out they didn't even attempt to shut the windows to minimize the sound. I offered to help them find a new place to stay but they refused and wanted to stay for free instead (during the busiest two nights of the high season! when they were paying pennies compared to a hotel.) I gave them a refund of one night but still received a lower star rating then I am used to. All other guests who experienced the same construction project still rated me 5 stars.
My point is, these guests are clearly looking for something, whether is it relocating or a refund. They brought what they think is an issue to your attention because they want you to fix it, even though you have no control over it. Try your best. I personally would relocate them to your other property. Show it to them first and explain that it is an upgrade for the inconvenience. But keep in mind that even though this construction actually worked in their favor, because now they get to stay in a nicer, better place, these guest might not see it that way.
Also, do you know how long the construction will take? Maybe it will be over tomorrow. Try to ask one of the workers what the projected timeline is.