Is Tyvec Absolutely Necessary?

dianna

I'm remodeling a 1970's home and would like to update the siding. There is no housewrap on it currently and I wonder how absolutely necessary it is to wrap it?
The other question I have is this: what are the specs on wrap around windows and doors? I've worked for a contractor who had us do it differently for every house we framed.
dianna

maj

Short answer... NO.. It's not absolutely necessary.

Long answer..... It may be required by codes in someplaces. I'm not sure about re-siding, but new construction is required in most places.

Windows & doors is hard to answer without knowing what you have. Basically, wrap goes under the window at the bottom & sides. over the nailing fin at the top. Here again, there is a longer version, with many ways to deal with it depending on the type of windows you're dealing with. Since we can't see your house from here, it is hard to give detailed descriptions.

Let me ask you, do you know why we use housewrap?
Is it for weather protection & possible water infiltration?
Or is it for air infiltration?

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Teetorbilt

A vapor barrier of some sort is required in most areas. If you want more details regarding ins., etc. ask.

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joasis

Due to you being up north, you may fall under the provisions of the Internation Building Codes energy requirement...you may want to consider that you can't afford not to have it even if it isn't required. It is like insulation..you only pay for it once.

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dianna

i figured it wasn't absolutely necessary and I also figure I will wrap the house, but I have heard different theories on the stuff and wondered if it wasn't just a win for Dow in their lobbying efforts. However, I also think that it is a vapor barrier, water barrier, has some insulating factor. Hmmm, did I answer correctly maj?

maj

Technical terminology for commonly known "housewraps" is Air Infiltration Barrier. Main purpose & the original purpose is for air infiltration. Some housewraps do provide some water protection, but others actually do more harm than good, IMO.

It definitely is not a vapor barrier, because it is permeable. It has no insulation value whatsoever.

With that said however, I am guilty of using the stuff all the time. Myself, I try to push using #30 felt paper in lieu of housewraps. Felt paper has been used for 100 years with excellent results.

If you MUST use a housewrap, use Tyvek, Typar or other non-woven type products.

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Mr. D

Hi, Dianna

There's a new tyvek wrap & stuff called green-guard. they are made with ripples in it that is supposed to to help moisture trickle down if it should get trapped behind the siding. I haven't used it yet, but they carry it at brown lumber. 30# felt does work great too.

Andersen wants the window r.o.'s wrapped in ice & water shield. Install window, Ice & water shield over flanges, tyvek over that, then tyvek taped. that was the word from the rep i talked to last fall.

I noticed you're from t.c. I'm in benzie. Feel free to contact w/ ?'s

dianna

Guess I blew that test, maj. I went to the Tyvek website and understand better now, guess I shoulda done that initially. Thank you Mr. D. for your explanation, I won't be able to put ice and water shield on the RO since the windows are in place, but I will definitely do the rest. With the guy I used to work for, sometimes we put the ice and water shield over the tyvec, sometimes we folded the tyvec into the RO and stapled it on the jacks inside. We never used tyvec tape because it was too expensive, or let me rephrase: we would maybe get one roll for a whole house. I needed some more input on it, so I thank you.

Grumpy

Short answer, is YES it is absolutely necessary if installing vinyl siding. Vinyl siding is not water proof, nor do any of the manufacturers claim it to be. Water does and will get behind your vinyl siding. Without a tyvek... it's coming in your house.

Tyvek is like skin for your house. It will allow air, and moisture, to pass outside but not enter inside. It allows your house to perspire.

Typically you can tape the tyvek to the window trim.

dayspring

Tyvek will also protect your exterior wall sheathing from the elements until siding is installed.

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MJW

Housewrap of some kind is required as far as I'm concerned. Tyvek is a brand name. I am doing alot of residing of houses that have vinyl siding and are about 5-15 years old or so because of hail damage. The ones with tyvek stayed dry on the outside. The ones without had water behind the siding. The houses with OSB on the walls, with or without housewrap have moisture in the walls (rusty nails). The houses with buildrite and tyvek stayed the dryest inside and out.

Cole

Yes, it is necessary!!!

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fredIII

the tar paper oils will drip down from behind the siding leaving black stains thru the weep holes.

MJW

I doubt it. It doesn't drip down onto fascias from the roof.

maj

For vinyl siding... yes. But for fiber-cement, stone, brick, cedar, etc..... I will still push felt paper over housewrap any day.

That's the trouble with vinyl.... it is only a facade... it just hangs there and lets all kinds of moisture in behind it. It's already happening now, but another ten years or so, vinyl siding removal & wall re-building will be BIG business.

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Grumpy

I've never seen that happen before and have seen siding placed on tar paper a few times.

Fred correct me if I am wrong please cause it's likley that I am. Weren't you a home owner in another thread asking for help on vinyl siding?

I ask because if so I think some siding sales person is giving you bad information. If not, then I blame my error on the lack of coffee.

maj

I agree Grumpy. I've been around the trades for 25 years and have never personally witnessed that. I have heard it could happen though.

Prolly just good sales tactics from Dow!!!

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DBell

Where does mold come from? Mold comes from damp humid spaces. Dark spaces that do not allow moisture to leave. In todays ever mold concious envioronments it is very important to use a product that breaths. Tyvek is the only house wrap that is tested and approved for the release of VAPOR. Tyvek is water proof. I repeat, Tyvek IS water proof. Tyvek Is tightly woven to keep out water and water drops. If a Contractor fails to seal the seams and fails to properly shingle the Tyvek, Water will get behind it. What happens next is: the water vaporizes and the water Vapor is allowed to exit through the woven fibers. Tyvek is the Inovator of house wrap. Thus creating a huge target for cheap or, not so cheap knock offs. Take a jar and fill it with water. Put Tyvek over the top, it will not allow water to leak through. It will how ever allow The small molecules inthe form of Vapor to pass through. Plastic with little holes punched in it is not a good house wrap. Tar paper is good for a few years, but after about ten to 12 looses its form and tends to break down. Tar paper also traps water after it gets behind it. Tyvek carries no true R-value. But does creat a dead air space when applied correctly. Apply Tyvek correctly and you will eliminate any water intrusions on you windows also. Simply stated, science is what Tyvek uses. Every one else tries to make a cheap imitation. Simple, use the Tyvek.

MJW

The only problem is builders that use OSB on the walls. It does not breathe. This is where the mold problem comes from. I use tyvek or house wrap for the purpose of keeping water out. That is the only reason.

DBell

You are incorrect, Tyvek lets vapor out . Where the el cheapo wrap does not. It breathes just fine. Tyvek even carries a semi rigid wrap used for stucco and hardi. Check it out might just teach an old dog a new trick.