Home insulation tips and contractors
Browse Topics
» Home page
» Spray Foam Insulation
» Fiberglass Insulation
» Cellulose Insulation
» Pipe Insulation
» Mineral Wool Insulation
» Plastic Foam Insulation
» Installing Insulation
» Electrical Insulation
» Building Insulation

Looking for the insulation contractor?
We will help you to find best contractors in your area for free! Just fill out this form.
Search questions
Browse and search our database of Q & A.
Ask a question
Ask a question and get answers from real people.
Answer questions
Help our users by answering their questions


Do you need a vapor barrier when using fiberglass insulation?



I have a greenhouse and there is a spot about 5 inches wide across the top where it is attached to the house that we put insulation and then covered it with plastic glazing does there need to be a vapor barrier on the insulation?

Answers:



From: John B.

Vapor barriers are used mostly on exterior walls and in ceilings to keep the moisture out.With fiberglass insulation it is a good idea to use a vapor barrier. Once fiberglass insulation gets wet it may lose it's insulation properties. I would suggest using rigid foam instead if possible. Otherwise I would use a vapor barrier and seal the insulation.


From: Ed comeau

Can I use tyvec as a vapor barrier after I put unfaced insulation up


From: bart

Tyvec is not a vapor barrier, it is an air barrier. It is designed to provide a draining plane for water to escape out of wall systems, it will absorb water if exposed for long periods of time. Use 6 mil poly vapor barrier instead


From: John

i have an easy rule of thumb that works for me. if there is more than a possible 30 degree temp differential from one side of the wall to the other, then you need a vapour barrier on the warm side. the vapour barrier just keeps condensation from permiating into the warm space.


Back

Add Your answer to this question:

Your name
Your answer
Confirmation code:993 Enter the code exactly as you see it into this box.


Powered by Yahoo! Answers



Need A local Insulation contractor?
Free Price Quotes From Local Insulation Contractors.! Just fill out this short form.

$Top Products
Popular Mechanics Weatherproofing & Insulation» Popular Mechanics Weatherproofing & Insulation
Price: $11    $8.95
The Science and Engineering of Thermal Spray Coatings» The Science and Engineering of Thermal Spray Coatings
Price: $624    $520.00
Thermal Engineering» Thermal Engineering
Price: $78    $65.00


?Questions & Answers
Resolved questions:
» I see a gal in a couple of the photos insulating a gooseeck trailer, and I have a similiar project. My ? is what is she attaching it with? Also I see a lot of steel showing, and if she just panels over this won't it condensate at the Metal studs?
» Use of scrunched plastic shopping bags as insulation (?)
» Does regular insulation block sound?
New unresolved questions:
» Radiant barrier insulation
» What is better for exterior wall insulation roxul or r-20 pink
» What's the best way to insulate under an existing bay window/bump out that overhangs a concrete patio?

» Ask a question
» Answer questions