Should I remove old linoleum when replacing a linoleum floor?

If you prep your surface first (clean it thoroughly), and it is mostly intact (especially at the edges) you should have no problems laying new rigid flooring over top. I have heard of kitchen remodels where they find 4-5 layers of linoleum!

You do have to account for the increased thickness with cabinets and appliances.

Removing old linoleum flooring is difficult to do and as long as the current linoleum is flat and level then you should be fine laying a new surface on top of it. With that said though, when I remodeled my bathroom I did remove the old linoleum to put a new tile floor down. I actually found removing the linoleum fairly easy as I was able to peel most of it up in a single sheet and then I just scraped the remaining loose adhesive off the floor before putting down the backer board. (But I am not sure this would be the typical linoleum floor removal experience... maybe my linoleum floor was not properly installed originally.)

If you are going to keep your current linoleum down, the biggest thing to watch out for is that the new flooring will add height and could affect the thresholds and/or appliances. In the case of my bathroom remodel above, it is a good thing I did remove the old linoleum because the new tile floor is just at the level of the threshold. If the linoleum was there then I would have needed to raise the threshold.

Many flooring choices can be laid directly over your old vinyl flooring, as long as it is flat and even. Keep in mind that anything you add to the floors on top of your old flooring will make the thresholds that much higher too; it can also impact any appliances that fit under the counter, like your dishwasher. You will want to consider this before you do too much work. You may find that the height change may cause a tripping hazard. Reference: http://www.theflooringlady.com/removing_vinyl_flooring_000805.html

In some cases (such as mine), you'll find that the old stuff isn't glued down properly, forcing you to remove it when you otherwise could have gone over top...

Remove the old layers. Rolling a heavy appliance (refrigerator) over the flooring can leave tracks (dented lines). This can be exaggerated with multiple layers. The tracks on my floor prove this.

I am a professional floor covering installer with 30 years of experience. I have 18 employees, and do all commercial work. I am a Forbo Master Mechanic. And the list goes on.

Almost all manufacturers state that you must install any new floor on a properly prepared substrate directly for your new floor to be covered under any warranty.

In California it is against the law to install a 3rd layer of flooring. The problem is you don't know where your weak link exists, and your new floor will most likely fail. All new floors will create stress in time, and pretty quick too. That being said you will have quite bit of stress in the form of shear. The adhesive you will most likely use will have enough strength to hold against shear, but at least one of the layers below will not. So my professional advice is don't do it.

As a professional this is a job I would walk away from, If I could not remove the existing material because a customer wanted to save money.

As far as Asbestos being present in any of the layers is concerned, there is a high likelihood. All 9 inch resilient tile has Asbestos in it. Most resilient sheet goods do not. No Linoleum has ever been manufactured with asbestos, and the two main ingredients in linoleum is actually Linseed oil, and Cork flower. That being said though, many of the mastics used prior to 1984 a percentage of chrysolite Asbestos material. Black mastic is a big red flag and needs to be sampled and tested from any structure built before 1984. This information is in the Code of Federal Regulations 1910. and it is also true if you are removing any painted surface i.e. baseboards due to the presence of Lead in older paint.

I removed my bathroom linoleum in my old house and was left with the black tar paper stuff stuck really good to the floor. After using water and a heat gun on parts of it, I discovered a trick and am excited to share. I used a wallpaper scoring tool called Tiger and ran it all over the black paper. I then put an old towel on top of it and poured very hot water with a little blue Dawn added to it all over the towel. I covered it with a sheet of plastic and left it for several hours. I was amazed that the paper scraped off with a 3" putty knife in huge pieces! Not little bits almost on fire from the heat gun. I know you will all say that it's probably asbestos but being wet definitely kept it from getting the air. Hope this will help someone!

Update: I did the above proceedure on a large area and left it overnight. The whole thing lifted up in one piece!

On the off chance that you are rebuilding an old house, you know the cerebral pain of old tile flooring. It is stuck down to the subfloor and can be such an agony to eliminate. They state you can just put your new floor on top of tile, yet my experience is it's in every case better to begin with a fresh start