DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Flooring (
-   -   Nails or screws for new underlayment ? (

Carlonious 08-21-2012 11:15 PM

Nails or screws for new underlayment ?
Hi, I am going to be laying 3/4" solid hardwood. I have removed my old carpeting and have been blessed with 5/8" particle board underlayment. :censored:
I will be replacing that with new 5/8" cdx on top of the original 5/8" plywood subfloor.
My question is: should I use screws or nails to fasten the new underlayment to the sub?
Thanks in advance for your advice and input.

joecaption 08-21-2012 11:33 PM

What are you planing on using for a finished floor?

JazMan 08-21-2012 11:34 PM

Hi Carl, welcome

First of all you should not be using CDX as an underlayment, it'll probably work ok for your new hardwood, but it's not the right product. CDX is a cheap grade and has voids in the center where you can't see them. Best to use underlayment grade.

Be sure to install in the same direction as the subfloor, (across the joists), and off-set to the subfloor both ways. You can use either nails or screws. If nails, ring-shank flooring nails, 1 1/4". Or flooring screws, NOT cheapo drywall screws. Leave an 1/8" space between sheets and 1/4" or more at perimeter and any solid object.


Carlonious 08-22-2012 12:33 PM

I may have used the term CDX in error - I was going to purchase from Home Depot this: 19/32 in. x 4 ft. x 8 ft. Rated Sheathing Syp Model # 166081 Store SKU # 166081.
I hope that is an adequate underlayment.
do I need to be concerned with replacing the paper vapor barrier between sub/underlay ? My installation is main floor, at grade, with a heated full basement below.My finished floor product is Bellawood 3/4" solid Country Red Oak.
Thanks for your input.

JazMan 08-22-2012 03:34 PM



I was going to purchase from Home Depot this: 19/32 in. x 4 ft. x 8 ft. Rated Sheathing Syp Model # 166081
That is not underlayment grade plywood. it'll most likely work fine, (especially under hardwood), but no where is it spec'd underlayment as you may have read. You should use this one instead;


Carlonious 08-23-2012 11:13 AM

Thanks again for your insight and advice. I was going on what the guy in the vest said. Which is why I went online for a second opinion. Which makes your response all the more valuable to me. I will go with your reccomendation and I will be using ring shank nails.

JazMan 08-23-2012 11:40 AM

Rule # 1 when shopping at the Big Box stores.

NEVER ask technical questions about your project. Only ask things like: "Where's the rest room"? :laughing:


All times are GMT -5. The time now is 01:18 PM.

User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.