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Author Topic: Need a vapor barrier under laminate?  (Read 2775 times)

Elly Dalmaijer

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Need a vapor barrier under laminate?
« on: April 02, 2011, 02:13:29 PM »
We have purchased laminate and the black underlay and are planning to install this in our 1993 27 ft Itasca Sunrise with no slides.  The area will be fairly narrow (2-3ft)  with the widest spot being from the dinette wall to the counter area, about 6.5 ft. 

We have two questions and would appreciate your input:
1. is there a chance (because of the free-floating installation) that in time the underlay forms ripples underneath the laminate?
2. do we need to install a vapor barrier on the sub-floor, underneath the black underpadding? If so, should the padding, together with the moisture barrier be stapled down to the subfloor in order to prevent the laminate from sliding all over the place?

I will describe the environment of our RV: we live in Alberta, where the unit is stored outside on a lot (no electricity), and where the temperatures in winter are mostly between 0F and -20F with frequent nights that are much colder (as low as -40F). The air here is very dry: 20-40% humidity. By March we like to take this motorhome to warmer places and it warms up to 70F-80F. Summers in Alberta also give dry air but the daytime temperatures go up into the 80s and 90s.

All this means that our unit experiences huge temperature fluctuations during a year , but that it is rarely exposed to a humid environment.

So: is a vapor barrier needed? So far on the general internet most seem to say NO, however I greatly value the input of the Framily and would much appreciate your advise.  Thanks!

Elly
Either at home in St Albert AB or working in Africa or in our 1993 Itasca Sunrise.

Gary RV Roamer

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Re: Need a vapor barrier under laminate?
« Reply #1 on: April 02, 2011, 08:37:52 PM »
You do not need a vapor barrier on a raised platform like an RV floor, but it doesn't hurt. Nor do you need to staple the padding down.  I've never heard of one rippling either - the under-mat is too tough and too stable for that.  But I've only installed 3 rooms full of the stuff, so let's hear from our resident flooring pro, Ernie Ekberg.

The laminate isn't going "all over the place", but it is supposed to be able to move a 1/4" if it needs to.  It is held in place by surrounding walls with moldings, or moldings alone at door ways and such.
« Last Edit: April 03, 2011, 09:15:05 AM by Gary RV Roamer »
Gary
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Gary Brinck
2004 American Tradition
2007 GMC Acadia
Homebase: Ocala National Forest, FL

Ernie Ekberg

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Re: Need a vapor barrier under laminate?
« Reply #2 on: April 03, 2011, 08:00:28 AM »
Gary is correct. The mat won't wrinkle. I'm sure you will need a shoe mould to anchor it down. You should be able to get a moulding close to the color of the floor.
Sorry I didn't respond sooner, was doing an all day inspection on a coach for a client.
Ernie Ekberg, Weatherford, Tx
Bluebird Wanderlodge 43
www.ernieekbergflooring.net

Elly Dalmaijer

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Re: Need a vapor barrier under laminate?
« Reply #3 on: April 04, 2011, 03:00:13 PM »
Ernie and Gary;

Thanks for clarifying this. Ernie do you also agree that we do not need a vapor barrier?

Thanks for sharing your expertise!

Elly
Either at home in St Albert AB or working in Africa or in our 1993 Itasca Sunrise.

Ernie Ekberg

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Re: Need a vapor barrier under laminate?
« Reply #4 on: April 04, 2011, 05:42:35 PM »
Yes, I believe like Gary mentioned, no vapor barrier required. Enjoy your new floor!!
Ernie Ekberg, Weatherford, Tx
Bluebird Wanderlodge 43
www.ernieekbergflooring.net

Gary RV Roamer

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Re: Need a vapor barrier under laminate?
« Reply #5 on: April 04, 2011, 08:16:50 PM »
I put an Armstrong laminate floor in kitchen and breakfast area of our double wide "manufactured home", which of course has a crawl space underneath. Plus we are in Florida, so the soil is sand and does not hold moisture at all. I contacted Armstrong Tech Support about my install, asking about the need for moisture barriers. The answer was none required when the soil is dry and adequate ventilation underneath. They recommended a crawl space height of 16" over moist soils, but felt less would be ok over a dry sandy soil.  They were more concerned about using it in kitchens and baths and briefed me on gluing the seams of any panels that were near a sink, dishwasher, etc. where water might get spilled. Idea is to keep water on top of the laminate (which itself is waterproof) rather than underneath.
Gary
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Gary Brinck
2004 American Tradition
2007 GMC Acadia
Homebase: Ocala National Forest, FL