Need some advice and guidance regarding installing tile on the floor of a small 5' X 5' bathroom.

The floor currently has a single piece of good quality vinyl sheet flooring I installed about 15 years ago that is still in perfect condition with no cuts, lumps etc. When I installed it, I first screwed and glued a piece of sanded 1/4" or 5/16" plywood over the 5/8" tongue and groove sub floor so I had a good smooth surface for the install. The vinyl sheet floor was then glued to the plywood where it has remained.

So my first question is can I reliably install cement board over the sheet vinyl then install ceramic or porcelain tile on top of the cement board?

If so, will 1/4" thick cement board be adequate and what do I need to do to prepare the sheet vinyl floor before installing the cement board.

Would appreciate your comments and suggestions.

Thank you

Dom

 

Nope. The vinyl and the 1/4" plywood need to come up and likely thicker plywood needs to go down. What's the size, spacing and unsupported span of the floor joists?

 

Well, there you have answered your own question, who knows!

If the bathroom is only 5x5, why not do it right and demo the existing floor and then you wont have to ask the question regarding reliability!

 

You guys just ruined my day.

How hard will it be to remove glued down sheet vinyl?

If I remove the sheet vinyl and 1/4" plywood, how thick will the new plywood need to be?

Is 1/4" thick cement board adequate on top of the new plywood?

Thanks for your input

 

Btw, the floor joists are 10" wide on 16" centers with a unsupported span of 12 feet

 

3/4" plywood is the norm, if you have just 5/8" another 1/2" will be sufficient.

Others say 1/4" CBU is good for floors, personally I always use 1/2" and feel 1/4" would be better for countertops!

 

CBU is not structural, 1/4" is fine for floors. Don't try to remove the vinyl, just rip up the 1/4" plywood it's attached to and then add the required extra plywood.

 

Vinyl is on top of the plywood, it all has to come off!

 

As Stickshift said, it comes off WITH the underlayment. Tearing the underlayment up removes the vinyl. Cut it all up with a skilsaw set 1/4" deep.

 

Thanks for your input everyone.

I decided to remove the vinyl and 1/4" plywood as one as was suggested. Although I couldn't remember whether I glued the plywood to the sub floor which I find today I didn't, instead I attached it with a million screws which made removal a pain but I'm getting there.

Once I get it all removed I'll be back for more advice.

 

Yeah you NEVER glue underlayment. It's usually stapled on, and the staples can be a pain too.