Siding Issue related to sidewall venting?
Recently we have identified occurances where the siding buckles, leaving a very wavey surface clearly visible. When the siding is removed the OSB sheathing is swollen and at times even popped away from the studs.
The photo below is a house less than six months old.
The locations are often related to the sidewall venting of the high efficient furnace. In this photo, there are 2 condensing furnaces and 2 condensing hot water tanks into an 8' sideyard ( 4' from property line).
The moisture levels are high (as can be seen below on sheathing removed during repairs) and the 3/8" sheets are swollen to 5/8".
Avoid - installing the OSB tightly - to prevent swelling that will cause the sheething and studs to seperate.
Avoid - offsetting vents ( 2 houses venting into the same side)
Avoid - venting under or around cantilevers, decks, build outs
Avoid - high permeability weatherbarriers that allow vapour to return through to sheathing
Avoid - Low permeability sheathings
Do - use more moisture resistant or durable materials
Do - Vent through the roof ( AWAY from roof vents)
Don't just apply one solution to every situation - a house works as a system
Some materials fall below building code requirements of 60 ng /Pa-s-m2 and can be very slow to dry once wet
Durable materials withstand moisture better than untreated lumber
Space sheathing to accomodate swelling
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