Horizontally running 2×6 T&G western cedar over 15# felt, 3/4″ sheathing, 2×4 studs, factory bagged, R13 fiberglass insulation, walls on overwater structure in the NW.
Tongue up. untreated cedar.
The 2×6 is to be nailed into at least 1-1/2″ of wood. I don’t plan to fir out to provide breathing space. I’m hoping the usually heated interior space will keep the moisture moving outward.
Anyone seen this arrangement result in condensation between the felt and cedar? Other problems?
Replies
Horizontal T&G ALWAYS traps water and accelerates rot in siding. Best to provide the extra breathing space behind it
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Piffin,
What is the minimum furring thickness that you have successfully seen used. 1/8" cedar strip run vertically every 2'? stapled and then nailed with the boards to the studs?
This is beveled T&G.
Run horizontally, surface tension pulls water up into and on top of the tongue and in the groove? Seems clear that water running down against the grain and board edges will hold more water than vertically applied boards whose groove and grain would tend to shed water or let it run less impeded.
Is this why your experience suggests breathing space is good practice?
Is horizontally run T&G more prone to getting water BEHIND the wood against the paper? Or is the typical problem of rotting more due to the difficulty and cost in flashing properly to KEEP the bulk water out from behind the boards?
Or is the furring in this case to get the wood to dry sooner by adding some drying of the bulk wood, which has absorbed moisture into it, from the back side?
The "real cedar" site http://www.cedar-siding.org/ mentions furring in wet regions in the "wall construction" section, but seems to lack emphasis. I will not be coating the cedar.
Have you repaired or demolished heavy, horizontally run cedar that had rotten prematurely? Or other properly applied siding which was mounted flush to the felt (without a vapor tight barrier)?
So do you (or anyone else) have experience in demo or repair that would give some insight.
Thanks for considering the question.
I ain't Piffin, but I like to use two layers of #30 felt for the furring. Cut it into 1.5-2" strips about 8' long and staple them over the studs. It gives you some air, but not so much room that your trim boards suffer visually. It also won't rot.
Wind blows water into brick walls all the time... it'll push water right past those tongues.
Letting moisture dry is always good for the materials... at least non-living materials.Troy Sprout
Square, Level & Plumb Renovations
That sounds like a good idea. i happen to have some nice heavy 30# roofing felt that should work. nice way to mark the nailing lines too i suppose.
For vertical and horizontally run cedar you use the strip method (obviously in different directions)? when the boards are run vertical, just staple in the strips to match the nailing lines (i have adequate block, beams, rim joists, etc so furring is not required).
seems like a great and easy way to get a little air, thanks.
You're certainly welcome!
Always vertical installation. Water runs downhill, remember?
Cheap, no mess, easy to carry and install, effective, helps with the nail-up, only costs utility blades, lasts forever...
I use it on ALL siding, including fiber cement. It's a bit of insurance that makes me more certain of longevity.
I love effective solutions!Troy Sprout
Square, Level & Plumb Renovations
Oh yeah, i forgot about gravity!
So if i run the siding vertical, then the furring strips (felt) should be narrow and run often to achieve the desired effect if run vertical as well? HELP!!
If the siding is run horizontal, it is obvious that the felt strips be run vertical.
On a garage where i ran a little vertical siding, i ran shorter intermittant sloped horizontal fur strips to allow for circulation and drainage.
I rip strips 3/16" for the furring out.Yes, I have demoed cedar direct over tarpaper hat was paint on outer surface only and not backprimed
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!