Construction technology has change throughout  the years, the need for a more energy efficient home has made  the construction industry  close every possible gap  within the home making the structure very air tight, while keeping an air tight structure sounds very appealing specially to the wallet, unfortunately  as we increase the  energy efficiency of the structure by using more air barriers, more insulation, energy efficient windows and doors we are reducing the amount of air  that flow through the walls.

Throughout my carrier I have seen  many builders and architects trying to increase the R-value of the structures paying attention to the interior elements of the system but totally forgetting  about the exterior, is very important to not forget the exterior which is the side of the wall  that  will be constantly expose to the elements and there fore the one that  needs a proper Water and Air management to  guaranty the longevity and the reliability of the structure to withstand decades of use and not only a few  years.  When designing a wall system is very important to pay extra attention to every element of the wall, such wood framing, wood sheathing, water resistant barriers, insulations but most importantly what kind of exterior cladding will be use, every exterior cladding has its own  different needs to make sure that it will  work as intended with the wood structure and not against the wood structure.

Rainscreens are  designed  to create a gap between the wood structure and the exterior cladding

So, why some sort of rainscreen or air gap between the wall and the cladding is so important?

No matter if the home is not insulated, improperly insulated or the walls are well insulated, the amount of water that the wall is exposed will not change.

Walls that are well insulated reduce the amount of air through the structure this also reduce the drying time of the wall, the less air the longer  the wall will take to dry, the longer the wall take to dry the risk of moisture problem increases,  that’s when a rainscreen mat comes into place…

With Stucco and stone been a cementitious claddings  a rainscreen  helps not only to protect the water resistant barrier to get in touch with the cement specially when using tyveck stucco or home wrap as your one and only water resistant barrier ,  it also creates a gap between the  water resistant barrier (the layer that is protecting your house from the elements)  and the actual exterior cladding ( the facade). The 3d designed entangled net mat eliminates incidental moisture problems by allowing the water to  drain and dry faster  and most importantly  allowing the air to flow more efficiently between the cladding and the wood structure preventing any wood  decay and water resistant deterioration.

 When performing new stucco installations or stucco remediations at Rene Munoz Plastering as part of our 3 coat stucco system, manufacture or real thin veneer stone system, we always install   a double felt tar paper over  tyvek StuccoWrap followed by the installation of a rainscreen mat, we get fantastic drainage between the back of the building paper and the front of the StuccoWrap as well as  the back of the actual exterior cladding. This is  our  approach of choice in my opinion for cement stucco applications.

To conclude this post  I would like to say that personally I have seen 100 year old houses with  what is consider  today as an improper  stucco installation, without or what is also consider as improper  interior insulation standing and  we have performed  many stucco remediations on properties that are getting insulated with an improper water management behind the stucco. I would like to make a quick  note that the problem is not the insulation neither other materials or interior procedures, the problem is always the improper water management behind the cladding whether is  stucco, stone or fiber cement siding which I will talk about its proper installation later in another  Siding post.