Flooring Tile - Tiles on vinyl floor

I have decided to install ceramic tiles over vinyl floor in my kitchen. My house is over 30 years by now, so I was afraid that the vinyl might contain asbestos. I started to cover the vinyl with underlayment boards by using flooring screws instead of nails to minimise the impact on the vinly. Can someone tell me if there is a better way of installing underlayment? I have installed almost half of the underlayment, I am thinking of using glue and using less screw. Please help.

Is the screwing itself a problem? We did this a few years back in a 330 SF kitchen and I wasn't strong enough to use the electric drill so my husband had to do it and it wore him out as well. Perhaps you could use the construction adhesive that you apply with a caulk gun? How big is the project?

Peter, what kind of underlayment are you talking about?

Thanks for the reply. This is a relative small project, the kitchen is about 160 sq. ft. I was concerned that the screws might disturb the asbestoes and cause it to release the deadly dust. I was thinking last night that since I have already installed half of the underlayment, and the damage, if any, is alread done, I will now have the disease, and since it will only attach me after 30-40 years, I would be long gone. :)

By the way, John, the underlayment I am using is called Multiply, some kind of harwood plywood.

Thanks again.

On the same subject,
I plan on doing the same thing in my kitchen and front hall which opens to the laundry. I'm wonder what surface would be best to have under the washer and dryer, on the new tile or the old Vinyl? I know the stove and Refridge should have tile underneath. how should I treat all the cabnets, what's the best molding for them?
Is it emparitave to have an underlayment over the Vinyl?

Thanks

why are you using multiply under Ceramic tile? I think cementboard would be a much better choice.
I use multiply for vinyl and fasten it with staples. They are 7/8 inch and I place them about every 4 inches and about 2 inches on the edges.

I understand that cement board is a much better choice, but I have a floor height restriction. I have used out door grade plywood some years ago when I tiled my bathroom and have no problem, that is why I use plywood this time. Plus this is a made for underlayment product, I suppose it must be better then plywood.

Cement board comes in 1/4 inch.