Your blogger's parish priest has recently introduced a mass recruitment exercise, handing out forms to encourage people to join church groups - Legion of Mary, Wardens, Canteen, Choir(s), etc etc. What was puzzling to me was that there was another section, "other voluntary work", which included categories such as electrical work, plumbing work, gardening, transport, tailoring.
I had a peek in the Catechism of the Catholic Church (CCC). CCC 2434 says
A just wage is the legitimate fruit of work. To refuse or withhold it can be a grave injustice.
I don't know how the finances of a parish are run. However, it would seem to me that if a plumber had a choice between two similar jobs, one paid and one voluntary, then the logical choice in order to pay bills and the rent is to go for the paid job.
Professions like electricians, plumbers, musicians etc etc require specialized knowledge, constant training and experience in order for them to make a living, pay the bills and put food on the table. I see no reason to deny them a proper fee (or a reduced fee, if the parish is short of cash).
UPDATE: Thinking about it again, I realized that my stand is not clear. I will not object if any plumber/tailor/electrician/musician/chef etc etc willingly volunteers his services for free. My difficulty is that the service form suggests that these services should be performed for free. Or to put it in this way, "you're a plumber/musician/chef/tailor, why don't you help the church?". More often than not, its a means for these people (and for many, the sole means) to earn a living. Therefore, I am arguing in this post that the services should not, as a general rule, be performed for free, in recognition of this simple fact.