There are a number of bodyweight exercises you can do at home if required. Adding some weight in a back pack will increase the intensity of these. There is a member who hasn't posted for a while JustinRVA who posted a link to 50 great bodyweight exercises several times in the bodyweight forum and that is good.
The difficulty with bodyweight work is getting the intensity high enough to get you maxing out at the 6 to 10 rep ideal for muscle gain. This is easier to achieve on upper body work but your legs are used to handling your weight so making them work hard with just body weight and a bit more often results in single leg work etc. If you are thinking not to bother with legs google image 'don't miss legs day' for some good reasons to train properly.
Supplements wise, don't bother. Eat well and you won't need to supplement your diet. The word supplement means covering for a lack of something. If your diet isn't lacking you don't need supplements, and if you are eating a typical western diet, especially for a construction worker you are getting more than enough protein to be converting some of it to fat now, so adding to it will add to your fat stores not muscle. Can't imagine why supplement manufacturers don't mention that a lot of excess protein is converted to lipoproteins aka fat, can you?