6 mil plastic under shingles

25 years old and there was zero felt on the roof .
Yes I was also pleased how great it was .
When we moved in I closed all places air could get into attic from the home also added exhaust vents on timers in both Bath rooms also added a dehumidifer in the basement for those times the humidity got above 50% .
This will be my last home so I want it as good as I can make it .

Hi Roy,

From reading some of your posts of late, I took it that you were against ventilating attic’s …

What goes here?

The vapor barrier is supposed to go on the warm side of the building envelope. On the other hand, this is similar to installing waterproof underlayment. I don’t know. I’d ask a manufacturer.

So… aside from not being self-sealing, how is this different from waterproof underlayment, which most people think is a good idea?

In order of relevance;

Cost of product and Labor

Physical Properties and matrix.

All serve the same purpose, keeps water out in case of shingle failure.
Someone I know said shingles are not waterproof. :mrgreen::wink:

Its true I have a product that can be out for 6 months before you have to cover it up with comp.tile ect…

wow comp on that low of a pitch and I see no stains or dry rot…:shock:

The problem with plastic is every nail will create a hole and not seal itself like ice and water shield will.
Cheap way out but as usual, you get what you pay for.

For any of you that may want more info may check this out:



not true…see my other post and look at that info…I have been roofing for 15 years and the newer felts will not do that…

Similar products coming out left and right.
Here is another one.
**[FONT=MyriadPro-BoldCond][size=6]WaterBlock® RU-200 INSTALLATION:
**[/size][/FONT][FONT=MyriadPro-Regular][size=4]WaterBlock® RU-200 must be installed above properly ventilated spaces, as per local building codes, and is considered to
be a vapor barrier. The roof deck must be swept clean of dirt and debris and be smooth and dry before installation.

[size=2]Similarto others I have looked at an all claim to pass the Nail Seal Ability Per ASTM D1970-01


If anyones interest is to make the roof breath, than the product to get is
VapourShield, which comes in at 59 Perms.


I was referring to the plastic.

It is a form of ice shield.
I have used it for years but it does drive up the cost , but its worth the effort.
Nails seal around membrane and ice damming can not happen if installed properly. I see its an IKO product. I am saying ,this because around 1980 there were fined by Quebec for quality control standards that were low and many call backs on there product.
They moved to Hacksbery Onterio.
I see the membrain should have been rolled down to make it sit perfectly flat on the decking Roy, so it can not condence with vapor in the bubbles.
You do not slip on membrane because the top layer is matted and not slippry unless you are applying it late in the years and have left it over night to permite frost to build up on the product…

Brian I do agree with you and they should be wearing 5 point harnesses. ‘‘BUT’’
I also have done many years of roofing and that 4/12 slope you can play tennis on and is no safety hazard. Unless you fall when you are walking on a sidewalk, then I would have or should say give my men the choice on 4/12 and lower.
Most roofers give the starter course to the most experienced for its the most hazardous and you are hanging over the roofs edge…
The starter course of any roof style must be payed attention to closely for ‘‘several reasons’’ including safety.
I use to start the men using 5 point harness at 5/12 and greater.
That’s just me and only giving a point of view…