Condensation Behind Vinyl Siding

fieldsj

Can anyone help me with a problem? A customer wanted me to put new vinyl siding on their home. I checked out the job and the current vinyl on the home is extremely wet behind the siding. The house is a wood framed house and has some osb sheating on the walls but mostly 1/2" foam insulating board with house wrap over that. The insulating boards and the house wrap are installed properly the best I can tell. Not sure why it is sweating like it is and what the proper way to fix it would be, I don't want to put all that siding on and have her tell me it is still sweating like crazy.

shoemaker

Are the stud walls insulated?
Heat transfer from inside will cause sweating behind the tyvek.

Patrick

Id put my money on a poor install. After a bad rainstorm, there could have been water trapped under that siding for who knows how long. We find this all the time when stripping off old vinyl to replace with new. There are weepholes in the even water gets behind, however we have found that some brands of siding tend to hold the water longer than others.

How did they even know they had a problem? Was the HO stripping off sections just for fun?

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Originally Posted by Celtic
Like I said...I'm sure you are very good at what you do ~ whatever that is and where ever it happens.

concretemasonry

Is there vapor barrier on the warm side of the insulation? If not, in the cold weather, moisture from the inside can condense on the inside/back of the siding under many different conditions.

House wrap is not intended to stop the flow of water vapor, only moisture.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

vinylguy

yes but tyvec is suppossed to be permeable! so it should not trap moisture i would have to think improper install somewhere. or the foam board is not permeable. check the high spots first to see whwer water is coming from.

concretemasonry

House wrap should stop actual water and water droplets. Vapor/air containing moisture is a different animal!! - Think of water vapor as something like an odor that can get through someting that is not impervious.

there is a source of moisture that should not be in the wall, so just cut off the source (usually in the interior of the home in a heating climate.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

Brock

who cares!! a perfect oppurtunity to upsale them. pull off some siding and scare the hell out them, then reach into your little satchel and pul out the photos of hailstones that have hit and gone through it (you can get hundreds of these on line). then take them to the cleaners for a some cement siding

DA1

Built my home 13 years ago and was under floor Hour ago and noticed moisture in one area of wall. on plate. This wall gets southern and western sun. Being cool at night 28 degrees, and daytime 55 degrees. Walls are 2 X 4 with r-19 insulation and 1/2 inch foam board in center areas and plywood corners. No House Wrap as they have now. Covered with vinyl 8" lap siding (double 4) Have not had sweating on exterior until this year. No Rain in 7 days, but most moisture is at point plywood and foam board meet. Siding is n't as tight as it should be and there is a lot of moisture behind vinyl. Looks like I need to redo.

welterweight

A proper install is paramount. That's why you should never let a guy who is a fireman but does construction on the weekends install your siding.
Second, you need a house wrap with a high perm rating and insulation that is permeable. Insulated siding is a great option.