How to Clean Old Unfinished Wood Floors

Hardwood floors add a lot to any home. The natural beauty of wood provides warmth and comfort in a way that is both visually attractive and durable. Properly cared for, hardwood floors which are over 100 years old can be as good today, as the day they were installed.

But what if those floors haven’t been properly cared for? Sadly, many hardwood floors have been covered by either carpeting or linoleum, often glued down to the hardwood itself. But even without covering the wood, many hardwood floors have been ignored; not properly cleaned through years of use. The dirt which gets ground into these floors can dull the finish and discolor the wood, especially in the case of open-grained woods, like oak.

Today, there’s a resurgence in interest in hardwood floors. However, most of what is installed in homes today isn’t real hardwood, in the sense that it was 50 or more years ago. Rather, today’s hardwood floors are usually composite floors with a hardwood surface. Making them that way saves considerably on the cost and makes them easier to install, while still maintaining the beauty of wood. But they’re just not the same. Anyone restoring an older home is going to want their original hardwood floors, if they can salvage them, rather than covering them with laminate.

But what can be done about the years of grime that have gotten into those floors? Age really isn’t an issue here, as much as how dirty the floor is. A relatively new floor can get dirty quickly, while a floor that’s 100 years old can look freshly finished, if it has been taken care of.

The first thing that needs to be determined is whether the floor is finished or is a bare wood floor. This is easily accomplished by pouring a little water on the floor. If the water beads up and stays on the surface, the wood has some sort of finish on it. But if the water soaks into the wood, no matter how slowly, the wood is probably unfinished.

There are a number of different ways of cleaning the floor and a number of different cleaning products available. Abrasive cleaning should be avoided, as it will damage the finish. The only time abrasives should be used on the floor, is if the intent is to remove the existing finish and refinish the floor. In that case, a floor sander will be needed to get the job done efficiently.

Before any cleanings, including water, are used on the hardwood floor, the floor should be swept thoroughly, either with a soft bristle broom or with a dust mop. Take care to ensure that all loose particles of dirt are removed, otherwise they can end up stuck to the floor, when cleaners are applied.

Damp Mopping the Floor

The most common method of cleaning a hardwood floor is simply damp mopping. This differs from wet mopping in that not much water is used on the mop head. If excessive amounts of water are applied to a wood floor, especially an older wood floor, there’s too much chance of the water soaking into the wood, causing it to swell. Doing this regularly will eventually cause the floorboards to loosen up and separate. It can also cause some of the finish to peel off the wood, if the water gets under the finish. Damp mopping should be accomplished once per week for most wood floors.

The other risk with using too much water is that it invites what is commonly called “dry rot,” which is actually rot caused by a wood-eating fungi that is activated by moisture. This is the same fungi that tends to eat at exterior trim on older homes, such as the wood frames around entry doors and garage doors. Excessive rot weakens the flooring and can eventually lead to the floor failing and needing to be replaced.

Cleaning Wood Floors with Vinegar

One of the best cleaners for hardwood floors is plain old white vinegar. Vinegar is all-natural, very inexpensive and won’t damage the floor’s finish. Yet it is acidic enough to break up dirt deposits and even food spots that the dog might have missed. Many professionals use white vinegar for cleaning hardwood floors, rather than a commercial product.

To use white vinegar, add one-half cup of vinegar for every gallon of warm water. Mop in the direction of the wood’s grain to avoid streaking, working with long strokes. Be sure to soak up any extra water with a damp mop, rather than leaving it sitting to dry. Vinegar can be used on the floor twice per month.

The one drawback to using vinegar is the smell, which some people find offensive. It is possible to buy odorless vinegar or a few drops of an essential oil can be added to the water and vinegar mix, allowing that to be what people smell.

Murphy’s Oil Soap

One of the most popular commercial products for use in cleaning hardwood floors is Murphy Oil Soap. This product, which has been around for more than 100 years, was specially formulated for use on hardwood floors. As an oily soap, this product not only cleans but treats the wood, much like applying mineral oil to wood will help to protect it. Once the floors are in good shape, this should only be used once per month.

The manufacturers of Murphy’s also make a “Squirt & Mop” product that is ideal for use when damp mopping, for taking care of small problematic areas and spills. The ability to apply the product only where needed helps to preserve the rest of the floor, while helping remove those dirtier areas.

It should be noted that some floor companies and floor care professionals do not like Murphy’s Oil Soap. However, its success is testified to by its longevity in the marketplace.

Chemical Cleaners

There are a variety of other commercially manufactured cleaners which are made for use on wood and wood floors. Each of them makes their own claims and they pretty much all work well. None of them should be used more often than once a month, letting damp mopping suffice for the rest of the time.

One thing to be cautious about is the difference between cleaners and polishes. Cleaners do what they say – clean. Polishes are not cleaners and are created to build up another film on top of the existing floor finish. This will “rejuvenate the shine,” but will do so at the cost of trapping any dirt between the original finish and the polish. Eventually the buildup will be so bad, that the only way to get the floor looking clean again will be to strip the finish off the wood and start over again.

What to do with Really Dirty Floors

If the hardwood flooring in a home is really dirty, it might be tempting to use harsh chemical cleaners to get it clean. The problem with this, is that there’s a risk of those harsh chemicals damaging the floor’s finish or even the wood itself.

In cases where the floor has been ignored for a long time, the secret is to clean it multiple times, either with a damp mop or a damp mop with vinegar added to the water. This is a harsh enough cleaner to break through the dirt and oily buildup. It will take time to do the multiple passes necessary; but that’s alright. Work in small areas, getting each one clean before moving on to the next.

unfinished wood floor
Unfinished wood floor, Paul Houle

Deep Cleaning Unfinished Wood Floors

Cleaning with water and vinegar alone may not be enough for unfinished hardwood floors. In those cases, it may take more to remove built-up dirt and stains from the wood. Unfortunately, due to its porous nature, wood can readily absorb liquid spills, some of which can cause staining.

Denatured alcohol and trisodium phosphate can both be used for deep cleaning bare wood floors, removing stains and dirt that has gotten into the wood’s pores. If the floor needs more restoration, then mineral spirits can be applied.

While mineral spirits is normally used for cleaning paint brushes, it is also a light oil that can be used as a wood finish. Many wood floors which were not finished with varnish were oiled instead, either with mineral spirits or linseed oil. Today, mineral spirits are also used for finishing wood bowls, platters and cutting boards intended for use in the kitchen. It conditions the wood well, providing a soft shine, while sealing the wood from any other liquids soaking in. It also happens to be food-safe, although that’s not an issue for the floor.

Refinishing Hardwood Floors

There may come a time when it is necessary to refinish hardwood floors. Dirt alone isn’t a reason for doing so; floors should only be refinished if the finish on the floors is damaged to the point where it needs replacement. In some older homes, floor finishes can be extremely scuffed, even to the point where the wood is bare. Another time that floors might need refinishing is when a floor covering has been removed that was glued on. Generally speaking, the process of removing the adhesive will require sanding to the point where the finish is severely damaged.

Before refinishing a hardwood floor, be sure that it is absolutely clean. Refinishing a dirty floor will just trap dirt into the wood, under the finish. It is not necessary to remove all the previous finish; but that finish will need to at least be scuffed with a floor buffer, so as to provide a rough surface for the new finish to adhere to. Only sand where necessary, to smooth out damaged or discolored parts of the floor. Please note that both floor buffers and floor sanders can be difficult to control on hardwood floors. Start out in the middle of the floor, especially if you typically cover that part of the floor with a rug. Get used to controlling the buffer or sander before getting near the baseboard. It can sometimes be easier to use a handheld pad sander or belt sander in corner and around the baseboard.

Either oil-based or water-based polyurethane can be used to refinish the floor. There is a possibility that water-based will cause some discoloration; so, before applying it, do a test spot in some hidden area. Oil-based finish is less costly, but takes longer to dry. Both finishes can be applied with a short-nap roller, taking care not to leave any areas with excessive buildup. Allow the finish to dry completely before walking on it or applying a second coat.

For the best possible finish, roll slowly, so as to reduce the number of air bubbles created. A synthetic floor finish applicator can be used to smooth out the finish and break any air bubbles, before they dry.

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