Housewrap required by code? and what if it was not used?
I am in climate 4A. I had a house built by a contractor in 2008. The exterior siding is stone, brick and dryvette. The contractor told us house wrap was not needed and did not use any housewrap such as Tyvek. The stone had tar paper under it and the dryvette system supposedly did not require it. Is there any reason to be concerned that the house wrap was not used? Also, is it required by code to have house wrap?
Is there anything that can be done now, after the fact, to achieve the same effect of the house wrap without removing all the exterior stone and brick? Someone suggested a commercial grade clear spray on the exterior to prevent water from penetrating and also a special paint on the interior drywall as a vapor barrier. Also suggested was installing energy recovery ventilators. I would appreciate any thoughts you may have on the issue. Thanks.
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Replies
Angie,
The more technical and precise term for 'house wrap' is a the 'weather resistant barrier (WRB)'.
Tyvek is a WRB and the tar paper you refer to is another effective type of WRB.
Dryvit is a synthetic stucco that is applied over rigid insulation. I'm not the stucco expert but I do know Dryvit and other 'exterior finish insulation systems (EIFS)' have had problems in the past and have adopted different installation practices over time to react to problems seen in the field.
I believe the latest recommendation for residential installations of Dryvit require both a WRB and drainage provisions.
In your question you are conflating two different water issues: (1) vapor movement through the wall assembly and (2) water infiltration from rain events. WRBs serve to protect from water infiltration from rain events therefore adding an energy recovery ventilator or painting with a vapor retarder paint does not address the omission of a WRB.
At this point there is nothing you can do outside of taking off your Dryvit finish. There is the possibility that there is a misunderstanding and you have a WRB. There is also the possibility also that the Dryvit was detailed well enough that you are not currently having problems.
One thing you could do is contact a local 'building forensic' professional. They are the EIFS experts and will be knowledgeable of common installation procedures over the years for your area. Because of the many problems with EIFS in the past many professionals have made a lucrative career investigating building damage and bringing the issues to court.
Angie,
1. Do you have any evidence of moisture problems in your walls? If you don't have such evidence, you may be worrying unnecessarily.
2. The correct name for "tar paper" is asphalt felt. Asphalt felt is a perfectly acceptable water-resistive barrier (WRB), as long as it is installed correctly, and it meets the code requirements for a WRB. To learn more about WRBs, see All About Water-Resistive Barriers.
3. Two of the siding materials on your house -- stone veneer and EIFS -- have been associated with a great many water-entry problems in the past. That doesn't mean you should worry, but it means that you should keep an eagle eye out for possible signs of moisture problems.
4. You mentioned an energy-recovery ventilator (ERV). An ERV is used to provide fresh ventilation air to a tight house. It has nothing to do with preventing the penetration of liquid water (rain) into walls. If your house is very tight, and your indoor air is stuffy, you may need a ventilation system, but this question is entirely separate from questions about the WRB behind your siding.