I am in the final prep stage before starting to lay my HW floor (3/4" Prefinished Bruce). I found that one corner in the blind end of a short hall is quite low. I used a series of smaller and smaller triangles to gradually build up and level the low area with 12 layers of 15# felt. The area is now level within the recommended maximum of 1/8" in 6 feet. In reviewing the Bruce - Armstrong instructions I now see they recommend building up such low spots with a maximum of 6 layers of 15# felt.

Will 12 layers of 15# felt cause problems with the floor? Would I be any better off using roofing shingles or perhaps 6 layers of 30# felt? See photo below.

Any suggestions and advice would be appreciated.

Also... it may not be apparent in the above photo but I started with the largest of the felt triangles on the subfloor. Then built up with smaller and smaller triangles laid on top into the corner. Another final layer of felt will run down the hall on top of this shimmed up area.

Is this the proper way to build up a low spot? Or should the smallest triangle be placed in the low corner and then built up with larger and larger triangles on top? Or does it matter?

Thanks for any replies and advice on this. ZT

I can't imagine any problems here.

Me neither, but i start with a smaller layer and gradually expand to fill in low spots.

Thanks Barquois! Thanks Jerry!
I appreciate your replies.

Would there be any advantage, or worth the time now, to reverse the lay of my felt shims so the smallest triangles are on the bottom with larger triangles laid on top?

You would probably be alright leaving it but if you reversed it you may end up with less layers.

How lo was the corner to begin with that you needed all that paper ?

Thanks again Jerry! I'll pull it up, switch it around and see what happens.

Hi Nick! It seems the low spot sloped down to about 5/16" to 3/8" right at the corner. I kept adding layers till the 6' metal straight edge running down the hall showed it all within 1/8". I just measured the height of the felt layers at the corner and it shows a tad over 1/4" from the subfloor.

I would have nailed a piece of underlayment and feathered it out with a shingle then felt .. That's just me ..