# Can I install hardwood flooring over an existing hardwood floor?



## Max1119

I am assuming not, but can I install a new hardwood floor over the existing old one? If not, what is the proper sub floor, 3/4" plywood? Can I use osb?


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## poppameth

We've run into this situation a few times recently. If you really don't want to tear out the floor you have, the best thing you can do is use a floating wood floor like Kahrs that click together and doesn't attach to the existing floor.


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## Marvin Gardens

The short answer is yes you can. You can install as many floors as you want to.

The problem is the transition to other rooms. This is what drives floor installations.

You can also put in any size of sub floor you want to. Again, the goal is to have a smooth transition to the other rooms.

If you do not have a smooth transition then people will be tripping over that and the Paramedics will know your address by heart.

So the goal is to make your floor the same height as the rest of the house.

You can use OSB.


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## DUDE!

Marvin got me going with the paramedics, anyway, you never realize the height of trim and doors and such until you start laying down a floor. Try going around the outer walls of the room with a scrap piece of the wood you want to use, you'll get an idea of adjustments you'll need to make. And, like Marvin stated, the transition from room to room is a toughy to deal with.


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## Max1119

Thanks for making some really good points about the trip hazards. Since this is for a rental property we will really want to keep that in mind with liability and all. I was originally just worried about the possibility of the expansion/contraction of the old hardwood disrupting the new, but it sounds like you are saying that won't be an issue. Should I assume I need to install the new hardwood perpendicular to the old? Also, if I tear up the old & install new, what is the minimum thickness subfloor I should use? The house is 100+ years old, so I am guessing I wont find any old subfloor under the old hardwood.


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## DangerMouse

it's for a rental? just use no-glue vinyl! pull it up and replace for each new tenant! lol 
if you're doing the whole floor area, all rooms, etc. with no transitions, i wouldn't try to remove old floor, i'd just gently pull baseboards and go over it. but be sure to also check door heights with a piece of flooring to make sure there's room there to add 3/4" too! you may need to shorten a door or two. for added strength, perpendicular is certainly the way i'd go. but will it be asthetically pleasing? your call there.

DM


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## Max1119

So if I go over the existing floor, I need to add 3/4" subfloor and then my new floor? Just want to make sure I am understanding all the details correctly. Thanks.

p.s. lol to your vinyl/rental comment. luckily, i'm doing the project with a friend who is trying keep as much of the building's character as possible, despite it being a rental.


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## DangerMouse

if you add subfloor, then the new height will be 1.5" higher! you almost certainly would need to do door work. flooring on old flooring with no new subfloor is what i thought you were asking us? my apologies if i misunderstood.

DM


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## Marvin Gardens

Max1119 said:


> Thanks for making some really good points about the trip hazards. Since this is for a rental property we will really want to keep that in mind with liability and all. I was originally just worried about the possibility of the expansion/contraction of the old hardwood disrupting the new, but it sounds like you are saying that won't be an issue. Should I assume I need to install the new hardwood perpendicular to the old? Also, if I tear up the old & install new, what is the minimum thickness subfloor I should use? The house is 100+ years old, so I am guessing I wont find any old subfloor under the old hardwood.


Being 100 year old means that there may have been a lot of people working on it over the decades. No telling what is under there.

My guess is that there are some diagonal boards running at 45 degrees to the joists. Then over the top of that there is the subfloor of some T and G and the over that is the floor.

In talking with some of my east coast friends they say that there is a possibility of a thin layer of concrete under there. This must be an east coast thing cause you won't find anything like that on the west coast at least that I have seen.

Remember that 100 years ago there was no plywood and no OSB. Mostly they did dimensional lumber.

My suggestion is that you just rip up the old floor down to the base and then build up from there.

Get your total distance from the boards covering the joists to the threshold of the floor in the next room. This is your total area you need to fill.

Then measure the thickness of the flooring you are going to put in. Most I have seen are 7/16 with pad.

Then subtract the thickness of the flooring from the total thickness and that will tell you how thick your subflooring should be. My guess from my experience it will be about 1/2" (and 7/16 osb will work).

You can also get some 7/16 OSB scraps and a piece of the flooring and but it down next to the transition and see how well it matches.

It doesn't have to be perfect as there will be a transition plate there to cover the joint. If you are within 1/8" that would be acceptable.

If you can get underneath of the joists, you might be able to see what is bridging the joists.


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## conpro

*Floors patrons*

:thumbup:Yes, certainly can be done, leveling is an issue, that needs attention. The other is that all the old floors need to be completely free of infestations. Then it it will also save on the costs of any extractions and removals at this stage or at a later stage. Simple self-adhesive materials are available, which are worth a try for being inexpensive and do not need tutorials to install. Many of them may also are very thin to give paramedics a rest. 

Happy Exploration!

Conpro

Cutting costs with New Materials Stick on new flooring

Well maintained floors Innovative building materials

Inexpensive yet interesting Alternate construction materials


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## wrangler

Max1119 said:


> I am assuming not, but can I install a new hardwood floor over the existing old one? If not, what is the proper sub floor, 3/4" plywood? Can I use osb?


One thing I didn't see mentioned in your post or the responses, was how bad are your existing floors? Have you totally ruled out the possibility of repairing them (sanding, staining, etc.) If you are trying to maintain the character of the home, this may not only save you money, but also the charm of well-worn old hardwood. Certain stains will not sand out or be hidden well with darker stain, but can often be replaced by a quality floor man. If the damage is extensive then repair may be cost prohibitive. If you do go with ripping up the floor, you may still want to have a floor expert come out and give you a quote, as they may want to salvage the 100 year old hardwood and thus give you a price break, or even check to see if the old flooring can be recliamed. While installing windows at a customers house, the homeowner was having her Florida room flooring covered with hardwood to match with the adjoining living area of the house. When I went back to deliver a replacement screen, I was surprised to see how well the transition into the home had been done and could not tell where the old floor stopped and the new began.


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## 4just1don

IF the existing floor is indeed past refinishing,,,I would second the vote for click floating floor,,they are SO thin you dont need to rip up old flooring. "IF" the old hardwood is smooth and sound,,,NO NEED to increase expense (or work)for underlayment,,,you have the BEST you could hope for,,,paper between and lay her down!!

OLD houses indeed have the 45 degree dimensional lumber as sub flooring and 'probbly' the hardwood right over that,,,thats the way it is here. Total height off joists would be slightly over 1.5" since hardwood was a generous 3/4 " as was the subflors used "HERE". More than likely the subfloor was put on before the wall partitions were put up so cutting that ALL out presents flush cutting probs and nail backs for NEW flooring anyway. unless it is way rotten,your making too much work for yourselves. Splice in new wood for patching bad and go.


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## dudeman

i know this is an old thread but i just wanted to say i live in NJ and i have an old house built in the 40s and i have original hardwood floors that DO NOT have any type of sub floor. its just 3/4 t&g nailed right to the joist. my floors are in bad shape with some crowning, cracking and splitting. i think they are to the point where it would cost more to repair them then it would to put down a floating floor. this thread has given me some justification on putting down new floor on top of my old one.
thanks for everyones replies


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