Questions about equalizing two different floor heights in the same room

Old 10-28-10, 04:46 PM
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Questions about equalizing two different floor heights in the same room

I need some advice on the best way to create a level sub floor in my bedroom so I can install a oak strip floor.

Here's my problem.

Before we bought our house 30 years ago the previous owner put an 8 foot addition on the master bedroom and the contractor who did the work did a very poor job aligning the roof, walls and floor and I've been living with it ( and correcting ) ever since. Soon after we moved in I noticed a drop where the original floor and the floor from the addition met. Since the room had new carpeting I decided to pull the carpet back on the addition and build up the floor with 1/4" luan plywood which just about leveled the two floors.

Since the original floor in this bedroom has oak strip flooring under the carpet I now want to install oak flooring in the entire room but I need to deal with the difference in floor height. I figure there's still a 1/8" variation between the new and original floor. Original floor has 3/4" thick oak strips on top of a 5/8" T&G plywood subfloor. The floor on the addition is 3/4" plywood from what I can tell plus the 1/4" luan I added.

I think to do the job right I need to remove the oak strip floor from the original part of the room and to also remove the 1/4" luan build up I installed on the floor from the addition. Then build up the floor in the original part of the room to the same height ( add 3/8" ) as the subfloor in the addition. I may also need to sand down any minor differences where the two floors meet before installing the new oak strip floor over the entire entire area ( the room is 20' x 15' plus two large closets)

My questions are as follows:

1. Does the approach I described above make sense?

2. What is the best 3/8" thick material to use to build up the original subfloor?

3. What is the best way to install the 3/8" material over the original subfloor? ie...screws and glue? something else?

4. Am I wasting my time trying to save as much of the original oak flooring boards as possible in order to reuse them? I don't believe the original hardwood floor was ever refinished so it has the maximum amount of material left.

I've searched the archives and read everything that seemed relevent but my situation is somewhat different so I wanted to ask the forum for some input.

I appreciate any help I can get.


Old 10-30-10, 07:50 AM
Join Date: Oct 2010
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Hey Targa, It sounds like you've figured out the elevation problem. It's basically a whatever it takes to make things level solution. Any 3/8" plywood should be fine, and probably a good idea to use tubes of liquid nail and screws. Plus if you use 2" staples when you install the Oak they will reach the original subfloor. Using the old material will do a few things. Installation will be more difficult, and sanding will be more difficult because the old wood will not lay up as nice and flat as new material. Another problem is difference in color. For example, if your original floor is Red Oak and has aged with time, any new Red Oak may look different enough to not be pleasing to the eye. Eventually the new should age as well and blend nicely. A couple of possibilities would be to mix the old with the new as you lay the floor, or use a darker stain color which would help hide the variation. Installing all new material would of course give a more uniform look. Hope this helps

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