# hardwood over crawl space



## jhcontracting (Jan 10, 2009)

Need some help here. I have two separate questions.
1. Customer wants to put 3/4" hardwood in kitchen that only has a crawl space under it. Is this recommended, and what would be the proper installation method? This presently two layers of 1/2" plywood on the floor joists.

2. Should tar paper be used under all 3/4" hardwood floor installations? Or are there times when you don't need it?
JHC


----------



## Metro M & L (Jun 3, 2009)

Checm your subfloor for moisture. Flooring and sub should be within 2% of each other. Tarpaper is cheap insurance; I always use it.


----------



## Mike- (Aug 20, 2011)

Metro M & L said:


> Checm your subfloor for moisture. Flooring and sub should be within 2% of each other. Tarpaper is cheap insurance; I always use it.


Good advice. You definatley want to have a moisture/vapor barrier regardless of readings IMO


----------



## KnottyWoodwork (May 23, 2010)

If the boards are over a certain width, I go glue down instead of paper.

And I vote tile for the kitchen. I've replaced too many kitchen floors from spills and leaks.


----------



## greg24k (May 19, 2007)

Regular 3/4" flooring or not you always have to maintain proper crawl space ventilation and you should have some sort of humidity level control, because even if a crawl space looks nice and dry, it could contain large amount of humidity, which will only spell out problems.

Like someone said, glue down Pre-finished engineered wood flooring with plywood backing which can be re-sanded 2-3 times will be the ideal for over crawl space installation and you don't have to worry about call backs.

Here is a sample, of engineered floor with plywood backing and the top layer can be re-sanded up to 3 times.


----------



## jamestrd (Oct 26, 2008)

keep in mind tar paper will only hinder, not prevent..so make sure pro[per conditions are addressed underneath.

any excessive rise in moisture underneath will transfer to subfloor, then to floor..and the flooring will cup.

felt will not stop this...
proper vapor barrier and insulating techniques underneath are far more important.


----------



## ernesto (Apr 11, 2011)

Why would you believe anything anyone told you on the internet? :laughing:


----------



## NK Flooring (Aug 21, 2008)

Talk to the homeowner and recommend a dehumidier in the crawl. The moisture in the crawl will eventually find its way up unless it is controlled. FCI has an article on why this is the best way to control water moisture from crawl spaces.


----------



## floorinstall (Sep 8, 2007)

the ground under the crawl space needs to be covered with 4mil or better poly with the seams sealed with duct tape


----------



## aptpupil (Jun 12, 2010)

ideally there would be 6mil poly in the crawlspace and aquabar b or tarpaper over the subfloor. but just fyi i have a 90 year old house with 5/16" x 2 1/4" facenailed white oak over a damp crawlspace and it's just fine with a rosin paper over the 3/4" subfloor and nothing more.


----------



## ernesto (Apr 11, 2011)

It's 6 mil minimum on the plastic and it needs to be black.

Here's the newest info on crawlspaces.

http://www.buildingscience.com/docu...-crawlspaces?topic=resources/cond-crawlspaces



http://www.greenbuildingadvisor.com/blogs/dept/musings/building-unvented-crawl-space


----------



## Mike- (Aug 20, 2011)

ernesto said:


> It's 6 mil minimum on the plastic and it needs to be black.
> 
> Here's the newest info on crawlspaces.
> 
> ...


That is some good reading right there


----------



## Foundation (Nov 15, 2011)

havn't read all of that yet but why must the plastic be black?


----------



## ernesto (Apr 11, 2011)

Foundation said:


> havn't read all of that yet but why must the plastic be black?


Keeps things from growing under it. The clear shyt will disintegrate after awhile too.


----------

