Plywood Over Linoleum

Eventually, any linoleum floor reaches a point where it needs replacing. While linoleum is a durable material, highly resistant to abrasion, it can only take so much. Eventually, it becomes damaged enough that it has to be replaced. But in most cases, we just plain get tired of it long before that, deciding that it’s ugly and needs to go. 

Removing old linoleum can be difficult and messy. Making matters worse, some old linoleum contains asbestos in its manufacture, and breaking it up to remove it can lead to dangerous exposure. Chances are that peeling up asbestos-containing linoleum probably won’t release asbestos into the air, because the asbestos is mixed in with the vinyl, which is safe. However, removing it becomes extremely dangerous, should you try to sand off the remainders of the linoleum which don’t just scrape up. It is asbestos dust, not asbestos embedded in other materials, which causes most of the carcinogenic damage. 

On top of that, linoleum which contains asbestos may have to be treated as hazardous material. That means that you will have to have a sample of the linoleum tested to verify that it contains asbestos, if you suspect that it might. If it does, you need to find a waste disposal company which will accept it. They will most likely require that you package all of the scrap linoleum, wrapping it in plastic and sealing it, marking the outside of the package or packages with what it contains. Disposal could be quite expensive. 

One indicator of asbestos is that this flooring was often installed using a black mastic, especially on linoleum tiles. This adhesive contains asbestos and may indicate that the flooring itself does too. 

This risk exists for any linoleum which was manufactured before 1970. However, even after the use of asbestos in vinyl flooring was banned, existing stocks were allowed to be sold. So it is possible that linoleum installed as late as the early 1980s could contain asbestos. 

So, what to do? Instead of risking lung cancer or even worrying about what to do with your old linoleum, you can simply install new plywood over the linoleum, then follow up with the floor finishes of your choice. This technique is commonly used by professionals in remodeling homes, as it takes less time and reduces the risk associated with removing that old linoleum. Here’s how to quickly and easily go about installing plywood over linoleum.

How to Install Plywood Over Linoleum

Installing plywood over linoleum can be a rather involved project, especially for a large, complicated room. Actually, the complexity of the room’s shape will cause you more problems than the size, as that will require more special cuts of the plywood. Nevertheless, you should be able to complete the work in a day. 

You don’t really need a lot of tools for this project, but I’d recommend having:

• Both a circular saw and a jigsaw 
• Profile gauge 
• Tape measure 
• Framing or drywall square 
• Screw gun or impact driver 
• Caulk gun 
• Flooring roller 
• Prybar and hammer 

Before you get started, you need to determine whether the subflooring under your existing linoleum is wood or concrete. Wood can include plywood, MFD and hardwood flooring. In all of these cases, you can install the plywood with wood decking screws or flooring nails. If it is concrete, you’ll need to use special screws rated for use in concrete. You’ll also probably have to pre-drill the holes for those screws. 

Dealing with Wood Trim

You’ll need to remove your baseboard and door casing before starting this project, as you will be raising the level of the floor slightly. This makes it an ideal time to replace your trim. If you’re planning on reusing it, care must be taken in removing the old trim, so as to not break it. You should remove the nails from the trim, for safety, immediately upon removing the trim. This means using new nails for reinstalling it. It is a good idea to mark each piece with a number and create a diagram showing where they came from, so that you can put them back in the same places. 

While it is possible to refinish and reuse stained and varnished trim, you may not be happy with the results. A lot depends on how the carpenter installed it. If they used finish nails, even from a pneumatic nailer, then there will only be small holes in the wood, which can either be filled or reused. As long as you use larger gauge nails to reinstall the trim, it should hold well. But if they used narrow crown staples to install the trim, it will be extremely difficult to remove those staples, without leaving obvious holes in the wood, which will need to be filled. 

Stained and varnished trim cannot be stained over again, making it darker or changing the color. However, you can use a stain and varnish mixture on it, such as the Minwax Polyshades line of products. When using these products, apply them with long, smooth strokes, being careful to avoid puddles, overlapping brush strokes, or drips. What you see, when you apply it, is what you will end up getting. Switching to a darker finish in this process can help to hide nail holes. 

If you are planning on using the same color for your stained and varnished wood trim, then you will want to clean up the trim, fill any holes with a matching colored wood putty and then apply a coat of varnish before installing. If there are any paint drips of splatters on the wood, carefully sand them off, before applying the varnish. 

Painted wood trim or wood trim that has been stained and varnished, can be painted and reinstalled. Be sure to clean dirt off the trim, with a degreasing cleaner, like Windex or 409 and fill all the nail holes in the wood. Allow the filler to dry, before sanding it in preparation for the paint. 

There is no reason to use a primer coat on trim that you are reusing, as the wood’s surface is already sealed. However, it is a good idea to apply one heavy coat of paint before reinstalling it, and then following up with another coat after installation. 

Installation Instructions

Before starting, you’ll want to plan out your work and buy the necessary materials. You should always buy a little too much, so as to ensure that you have some extra, just in case of a cutting error or the layout of the sheets causing more waste than expected. 

Your home may have been built with the linoleum flooring running under the base cabinets in your kitchen or bathroom. In those cases, you’ll want to run the new flooring up to the cabinets, not remove the base cabinets to install new flooring. However, this will leave a slight gap, so you need to plan on installing a baseboard to the toe kick of your cabinets. This is usually ½” thick plywood or MDF, so there is no problem nailing or gluing to it. 

Don’t grab just any plywood for your project. Choose the best type for the flooring you plan to install on top of it. For example:

• ¼-inch exterior grade AC plywood is ideal for laying under vinyl flooring of various types.
• ¼ to ½-inch exterior grade plywood works perfectly under hardwood floors.
• ½-inch AC exterior grade plywood can be used as a replacement for fibercement board or cement board under ceramic tile.

It is best to use tongue-and-groove plywood products for this project, so as to avoid the risk of edges not meeting up evenly. The edges of the plywood have to be exactly level, if you are installing new vinyl flooring of any type. That can be accomplished through filling and sanding, but it is easier to accomplish it with tongue-and-groove plywood. 

Now, on to the installation. 

1. Before beginning, remove all furniture and appliances from the room, anything that sits on the linoleum floor. 
2. Scrub the linoleum floor well, using a floor cleaner that is designed to remove grease. Any grease left on the linoleum will prevent the adhesive from bonding to it. This could lead to loose, squeaky spots in your new floor. 
3. Sand the linoleum with 120-grit sandpaper to remove the gloss and provide some texture for the adhesive to “bite.” Be sure to wear a dust mask and goggles for protection while doing this.
4. Sweep and mop the floor after sanding it, being extra careful to remove any foreign matter in the process. Even grains of sand can cause problems with the plywood sitting flat and level. Once the floor is clean, take care to avoid allowing anyone in the room with dirt on their shoes. 
5. Find the longest wall in the room, with the furthest corner from the doorway. This should be your starting point for installing the plywood over the linoleum.
6. Check to see if that corner is exactly square. You can either do this with a framing square, or with a tape measure. Measure and mark a point exactly 3’ from the corner on one wall and exactly 4’ from the wall on the other corner. The distance between these two points should be exactly 5’ if the corner is square. 
7. Snap a line 4’ 1/4” from your long wall and the adjacent wall, parallel to the walls. These will be your guide lines, not the wall itself. 
8. Starting from the corner selected, apply a thin layer of construction adhesive to the floor, where the first sheet of plywood will be installed. Be careful to avoid leaving lumps, especially lumps which contain foreign matter. 
9. Set the first sheet of plywood into place, aligning it with the snapped line. 
10. Using the appropriate screws for the floor beneath the linoleum (as mentioned above), screw the plywood into place. Screws should be positioned no further than 16 inches apart from each other.
11. Continue installing full sheets, butting them up against the first sheet and ensuring you don’t leave any gap. You may need to cut the end of the first sheet on each row, to match the wall, if the corner isn’t exactly square. You should also cut the first sheet in the second row in half, so that the joints can be staggered. 
12. It is usually best to install all full sheets, before cutting and installing partial sheets, unless that partial sheet only requires minimal cutting. 
13. Roll the floor with the floor roller to ensure that it is pressed down all the way into the adhesive. If you don’t have a floor roller, you can accomplish the same thing by using a cloth pad rubbing it across the floor while pressing down on it. Walking on it will work as well, but may leave spots that are not pressed down all the way. 
14. Cut and install the remaining odd-shaped pieces of plywood, being sure to remember entryways and areas which are normally hidden, such as under the stove. 
15. Roll the floor again, to ensure that the added pieces are pressed down fully. 
16. Check for any edges which are sticking up higher than they should. If any are found, check that the screws are driven fully into the plywood and add more screws as needed. 
17. If you have used plywood thicker than ¼”, you may need to buy a transition ramp and install it at door openings. These are usually made of hardwood and come already varnished. 
18. Allow the floor to sit overnight, so the adhesive can dry. Check the edges of all pieces again, verifying that you don’t have any gaps or high edges. If you do, putty them and sand them smooth, before installing your new floor covering. 
19. If you are going to be carpeting this room, you can reinstall the baseboard and door casings now, being sure to keep it ½” above the new subflooring. However, if you are installing vinyl flooring or tile, it’s best to wait until after installing the floor covering, before reinstalling the trim. Keep in mind that you will need to cut off your door casing, and may need to trim off the bottom of your doors, to account for the thickness of the plywood and adhesive. 

Once the new plywood subfloor is installed and you are satisfied that it is level and smooth, you are ready to install your new floor covering. 

Tips for Success with Installing

Installing plywood over linoleum is a very simple, straightforward task. It’s easier and much neater than removing old linoleum. This being said, there are a few ways you can make the job even easier on yourself and get even better finished results so that your floor is smooth and ready for your choice of floor covering.

• Consider how much height the new plywood floor will add to the room. While ¾-inch plywood provides a very sturdy platform on which to install hardwood flooring, laminate, or new carpet, the combined height of the plywood and the new flooring can interfere with a door’s ability to open and close smoothly, plus you’ll need to build or buy a transition ramp to prevent tripping.
• Consider using tongue and groove plywood. Your seams will be tight and your floor will be more stable.
• If you need to cut your plywood to fit into tight spots, you’ll find it is easiest to accomplish with a jigsaw, rather than a circular saw.
• Leave ¼” of space along the walls to allow for expansion. The baseboard will cover this. 

Removing the Asbestos-laden Flooring Safely

There may be times when it makes more sense to remove the old floor covering, rather than covering it with plywood. This would be especially true in the case of floors which have a lot of damage or missing tiles. The unevenness in the floor, caused by the damage, can end up causing problems. 

Of course, you can make up for that unevenness and eliminate a lot of the potential problem by using thicker plywood, ½”, 5/8” or even ¾”. While ¾” thick plywood may seem a bit excessive, ½” plywood will work well to bridge these gaps and provide a solid subfloor. Be sure to put a bit extra adhesive in any places where there are floor tiles missing, so as to fill the gap. 

If you decide that you want to remove the old linoleum flooring, rather than covering it with plywood, you can either sand it off with a flooring sander or use a scraper to remove it. However, if there is any chance of it containing asbestos you should avoid sanding it and scrape the old floor covering off instead. A long-handled flooring scraper is ideal for this. 

I have found that a thin flooring scraper works better than one made of thicker material, as the thinner one will cut through the vinyl and/or can take advantage of any gaps under the flooring. If your flooring scraper is thick (such as more than 1/8”), you can thin the edge down with a grinder, but don’t sharpen it, as that will lead to you digging into the existing subflooring with it, causing more damage that you will have to repair. 

Scraping isn’t perfect and will usually result in leaving some of the inner layer of the vinyl flooring behind. This is where you would normally use a belt sander or flooring sander to finish the job. But as I’ve already said, you don’t want to do this with flooring that contains asbestos. Instead, soak the remaining scraps of flooring down with water, allowing it to soak into the material and adhesive as much as possible. Then scrape it again. This will soften what is left, allowing it to be removed.