Hi,

We were due to stay at the RIU Falesia in June 2005 but were offered offered alternative accomodation due to building work in the area.
When we were there we went to see the RIU Falesia as a matter of interest and i can confirm that a large hotel is being built directly across the small road from the hotel. If you are on the side of the hotel facing it then I would imagine there will still be quite a bit of noise as the new hotel was only a shell when we were there last June. You would also be affected by the work i'm sure if you stayed in the RIU Palace Algarve.
By the way as a matter of interest, if you check the official RIU website http://www.riu.com you will see they are offering heavy discounts at both affected hotels!!!