Hi John,
Thanks for reposting this question in a new thread.
To find out how potentially popular a niche is use this tool and type in masonry, then other related key phrases.
Free Keyword Suggestion Tool from Wordtracker
Masonry for example has 296 searches. (I think that's daily)
Then Google: allintitle: masonry to see how competitive it is.
allintitle: masonry - Google Search
669,000 competing pages in Google. That's because it's a single word.
Then scroll down the Wordtracker keyword list above to find other key phrases people search for that contain the term masonry.
A phrase like allintitle: "stone masonry" only has 12,700 competing pages in Google.
Then look at paid ads to see if any have affiliate programs. I just happened to see this one.
Pays up to $12.50 per lead.
Need contractor - Get Masonry and Stucco Quotes
Search for home improvement affiliate program and you'll find more.
You can also join programs like Ace Hardware and link to masonry products.
I don't know this market at all so just throwing out the basic niche research steps and a couple ideas.
Hope this helps and best of luck!