So here's the deal..

50+ year old house with what I'd assume are 50 year old solid hardwood floors which are at the end of their useful life. There's going to be in the region of 1000sqft of Engineered flooring, which is split across two levels of the house (it'll be floated).

First level is above the basement and has a subfloor at 45 degrees over the beams and the existing solid is over that. The upper level I don't know what the subfloor is, or if there even is a subfloor between the solid and beams.

Question is: should the solid be ripped out before laying the new floor (risking finding only beams under the upper level floor) and adding a lot more work to the job, or will I be OK laying new over the old?

If I can keep the old down, what thickness of ply would I need to add before I can run the new floor in the same direction as the old? 1/2"

And finally, if I can keep the old and add ply, presumably I still need a 'cushion' between the ply and the engineered?

You will have a subfloor UNLESS you have T&G boards running horizontally across the joists. I have seen this on second floor homes built from the late 19th century to pre- WW11.

You can lay a new floor over the older existing floor IF you take the necessary steps. Re-nail or screw down any loose floor boards. Flatten the old floor to within manufacturer's recommendations. Lay the new floor at 45 to 90 degree angle to the old floor's direction OR lay 1/2" plywood underlayment over the old floor to be able to lay a new floor in the same direction. Check for height clearances before adding more flooring to the existing floors.

It depends on what you are installing and how it is to be installed. If you are installing a floater, you will need a "cushion" as you call it. You could also skip the 1/2"underlayment. That underlayment is only needed if you are nailing or gluing. When nailing, we typically use #15 asphalt felt for 3/4" solid or thinner paper products like Aquabar for thinner nailed floors.

Thanks for the response..

The new floor is BR111 Triangulo Engineered and will be floated. I've decided I definitely want the new to run the same direction as the old and my measurements say I'm not going to be able to lay 1/2" ply plus the new flooring over the old due to an exterior door.

Sounds like ripping up the old is the only way forward, right?

Pete,

I guess you didn't see this comment in my reply.


So you can skip the 1/2" plywood IF you are floating your new floor AND the existing floors are "sound", solid and flat.

I saw the comment, but I guess I wasn't sure if you were saying I can run the new in the same direction as the old - without the plywood - if it's a floating installation..?

I thought running in the same direction could only be done with a ply layer between old and new - are you saying that on a floating installation, that rule goes out the window?

A floater is not attached to the solid wood flooring, which has moving characteristics. Since your not anchoring into the solid wood, you can run the floating boards in any direction you wish, as long as the existing floor is stout and not saggy between the joists.

Yes, that is what I meant and attempted to say.

Thanks guys