Beginner Builder Question – mesh vs furring for rain screen on cedar clapboard?
kelsea_anderson
| Posted in General Questions on
I am building my first home as a homeowner – I will have cedar clapboard siding, but I need to decide on installing some type of mesh verses furring/strapping underneath.
What are the pros and cons?
I am using #30 tar paper, no exterior insulation.
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Replies
Kelsea,
To my mind mesh is an alternative you choose if the type of cladding you are using is not suitable for mounting on furring, or there is some other impediment to installing a full rain-screen. So better than no gap, but lacking some of the major attributes like a capillary break and any useful air movement.
The rain-screen (furring) has two primary functions. Drainage and drying. The mesh will only get you drainage, for example -- driving rain that gets behind the siding can drain back out the bottom. However the mesh does not provide a big enough gap to act like a little chimney that will allow drying through the entire wall assembly. I would say furring is always a better more robust choice. It will be more expensive and complicated to detail. The only time I would say mesh makes more sense is when you insulate with some sort of foam that is effectively impeding moisture transfer through the wall assembly, in that case the benefit of drying is kind of irrelevant.
strausjw,
“(furring)... will be more expensive and complicated to detail.”
That hasn’t been my experience. Furring is cheaper and faster to install. The detailing may seem more complex the first time you do it.
"The only time I would say mesh makes more sense is when you insulate with some sort of foam that is effectively impeding moisture transfer through the wall assembly, in that case the benefit of drying is kind of irrelevant.”
The drying function of a rain-screen isn’t just for the parts of the wall from the WRB inward, it also protects the cladding, so I don’t think it becomes irrelevant if there is an impermeable foam layer.
I’d say the primary benefit of any rain-screen is as a capillary break. A cavity that sees actual drainage from the bottom is one that is experiencing failure.