House wraps

[Guest guest]

Hi. The outside of my house is moldy from splashback from the deck. The mold

went clear through to the other side of the 1/4 " hardwood exterior. The wood was

not sealed or painted. This is all that's on the outside of my house - no

siding. I will be replacing the moldy wood with plywood & then metal roofing I

can get for free.

My contractor wants to put Tyvek Home Wrap between the metal & wood - or Grace

Bituthene. Since I can't afford to side the whole house it will just be the

bottom 3 feet or so. I would think it could get wet, damp or condensation with

this assembly. I am thinking something a bit different should be done. I'm

thinking at least Tyvek Drainwrap & maybe even furring strips before putting on

the metal. I was even thinking a few inches gap between the metal & wood! Any

thoughts about this project?

Thanks.

[Guest guest]

Hi, .

You are definitely on the right track. One of the " gaps " is called a

" capillary break " and the other is called a " drainage plane. "

The " break " prevents moisture from wicking upward through

small spaces (like up a soda straw or to the top of a tree). One of

the most frequent situations is sheet rock touching the floor or

crawlspace insulation touching the soil. Moisture can wick upward

as much as two feet. The " plane " allows moisture, if it gets

between layers, to drain down and out by gravity instead of

staying trapped.

The gaps are best. The house wrap or bituthene can help but

needs to be installed in a way that doesn't create a double water

barrier. You can find details on barriers at

http://buildingscience.com/

There should also be a gap between the soil and the wood and

between any sprinkler heads and the side of the house.

Carl Grimes

Healthy Habitats LLC

-----

Hi. The outside of my house is moldy from splashback from the deck.

The mold went clear through to the other side of the 1/4 " hardwood

exterior. The wood was not sealed or painted. This is all that's on the

outside of my house - no siding. I will be replacing the moldy wood with

plywood & then metal roofing I can get for free.

My contractor wants to put Tyvek Home Wrap between the metal & wood

- or Grace Bituthene. Since I can't afford to side the whole house it will

just be the bottom 3 feet or so. I would think it could get wet, damp or

condensation with this assembly. I am thinking something a bit different

should be done. I'm thinking at least Tyvek Drainwrap & maybe even

furring strips before putting on the metal. I was even thinking a few

inches gap between the metal & wood! Any thoughts about this project?

Thanks.

----------

The following section of this message contains a file attachment

prepared for transmission using the Internet MIME message format.

If you are using Pegasus Mail, or any other MIME-compliant system,

you should be able to save it or view it from within your mailer.

If you cannot, please ask your system administrator for assistance.

---- File information -----------

File: DEFAULT.BMP

Date: 16 Jun 2009, 0:10

Size: 358 bytes.

Type: Unknown

[Guest guest]

Thanks Carl. I think I've read every Building Science document. :-)That's where

I got the idea. Have you ever seen what Tyvek DrainWrap or Tyvek Stucco Wrap

looks like ? I e-mailed them but they are not responding. I'd like to know how

much gap these products have. Bldg Science says you need 3/8 " .

Would it work to put up regular Tyvek right against the exterior wood & install

the metal on furring strips? I've seen products that are like furring strips

that also have horizontal notches. So I thought about short lengths of furring

strips instead of full length. Being as I am only doing a few feet on the bottom

I think I have to be extra cautious.

>

> Hi, .

>

> You are definitely on the right track. One of the " gaps " is called a

> " capillary break " and the other is called a " drainage plane. "

>

> The " break " prevents moisture from wicking upward through

> small spaces (like up a soda straw or to the top of a tree). One of

> the most frequent situations is sheet rock touching the floor or

> crawlspace insulation touching the soil. Moisture can wick upward

> as much as two feet. The " plane " allows moisture, if it gets

> between layers, to drain down and out by gravity instead of

> staying trapped.

>

> The gaps are best. The house wrap or bituthene can help but

> needs to be installed in a way that doesn't create a double water

> barrier. You can find details on barriers at

> http://buildingscience.com/

>

> There should also be a gap between the soil and the wood and

> between any sprinkler heads and the side of the house.

>

> Carl Grimes

> Healthy Habitats LLC

>

> -----