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I have spent the last 7 months building my dream house, and I read in my latest FH that when cedar siding is applied over housewrap that water will leach tannins from the cedar and clog the pores of the housewrap, causing the siding paint to fail.
This is disheartening, because I have just wrapped thew whole house with Tyvek, and am planning to shingle over this (siding, not roof) with cedar shingles. Will the shingles do the same thing as Joseph Lstiburek described?
If it was cedar siding, I would backprime the boards as he recommended, but I don’t want to paint the backside of the shingles because I want them natural on the outsaide and I’m worried about slopping primer around to the “good” side, especially after I’m on to the 20th bundle and gewtting careless.
What is a good way to preserve the look of the natural cedar shingles. I know they’ll age, but I’d like the house to age gracefully. We are at 3500 foot elevation in Northern California, so we have hot summers and some snow in the winter.
Any suggestions? Jay Storer
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Jay, while you don't indicate white or red cedar, you've got a problem with direct cedar-tyvek contact either way. Add thin furring strips over the tyvek for the cedar to rest on, or use a product like Benjamin Obdyke's Cedar Breather over the tyvek. Fasten with stainless steel ring shanks.
For finish, we've used Cabot's Bleaching Oil with good results. It's an accelerator with a slight "Cape Cod Grey" tint.
Another option would be to use Cedar Valley's siding panels, over your existing sheathing.
If you need links, post a reply.
*You might pull down the housewrap and make it into envelopes. Then cover the walls with #30 tarpaper, lapped over the flashings. From what I've read and from the scientists I've talked to, the reason that tarpaper is less liable to be damaged by tannin bleed than are plastic housewraps is that tarpaper is thicker. And #30 is thicker than #15. You could also leave the Tyvek and undercourse the whole job, dip-priming those shingles. The succeeding layers should hide the primed layer. Be careful with the wet primer, though. Latex paint contains surfactants, and the solvents in alkyd paints degrade housewraps.George's ideas are good, too. And he does it for a living, now, unlike me, a ustado. The question in my mind comes down to dollars and cents. Which of the workable solutions costs the least?Andy
*Jay,Whether you prime, paint, or stain the shingles, they should be laid up on furring strips. You will simply get the longest life out of the shingles if air can get behind them. This keeps the long term moisture level down; letting them dry after rain or as vapor passes through them. If the backs are allowed to dry they also do not cup. Keep in mind you will likely have to adjust the depth of your trim package as well; i.e. widows, doors, corners, frieze etc. to compensate for the depth of the furring strips.As for keeping the shingles from greying and/or blackening use a dip tank and brush to seal them with some natural toned sealer. Seal all sides prior to putting them up! Or don't seal any sides. They will cup immediately after the first rain if just one side is sealed. I'd keep the house wrap up under the furring strips. You want air to get under the shingles not into the house.David
*This discussion makes me nauseus. Spent countless hours last year applying white cedar shingles, unprimed, over a generic housewrap (lumbaryard name on it - probably tyvec, right?)on my 1200 sq ft addition. Can't imagine taking it off. Inside, used 6 mil plastic on the studs for vapor barrier and kraft-backed fiberglass batts, and 1" foam with foil on both sides, between the studs against the plywood foil (I know, some vapor will get through, but i was trying to cover those billions of little holes made by the shingle nails). Do I really need to take it all off? If I leave the shingle unpainted or use a fairly porous treatment (like what?) which I was not planning to do, will that allow enough moisture to escape so I won't have to worry about rot? other thoughts?
*JayHere is an example of the method David Taylor described. Western red handsplit shingles installed over 1x3 furring with Tyvek under the furring. Fasteners were SST ring shank nails, .078 dia. The shingles were dipped in Behr Natural Seal No. 30 (White cedar tone). It's been up 5 years with no change in tone (would depend on weather and sun exposure of course). Whatever you use to protect the shingles, make sure it's a semi transparent penitrating stain with a pigment if you want to maintain the tone for a long period of time. Some natural tone stains are almost clear and offer no protection as far as UV therefore turning the shingles gray then black.As a side note. Applying any sort of sealer onto western red cedar will make it darker. The lightest color possible is that of a clear sealer applied (the same as dipping the shingle in water). This was the desired color on this house. To achieve this, a light pigmented stain was used to reproduce the "natural" wet color without darkening the wood too much yet still offering good UV protection due to the pigment in the stain.CM
*David DLook at it this way. If you take them off now it's going to cost you time and money (new shingles to put back on plus what you blew on what you have now). It'll cost you the same down the road if you have problems so forget about it and leave it. Deal with it when you do have problems. Until then don't lose sleep over it.CM
*Leave the Tyvek, furr it out, dip the shingles and party on.If you hadn't planned on furring, check out your window/door trim and corner boards for eventual reveal before you plod onward. It's easier to furr the windows and other trim out now, if required, then to realize you need it when you start running shingles. If so, re-figure your interior jamb extensions as well.All stainless fasteners.Anybody out there use Cedar Breather on a regular basis...ie, do you like it?
*i've used it..i like it ... i'll use it again.. but not on sidewall...only wood shingled roofsin our climate , coastal RI, about 33 inches of rain a year..15 # felt, cedar shingles , either hotdipped galv. hand nails, or SS ring shank coli nails...
*b WBA At Your ServiceMike, why not on sidewalls ? What kind of gun are you using to shoot SS siding nails ? Thanks
*I have two words for you all ...rosin paper. Much better than anything else for sheathing paper especially under shingles. Jay, I ran scraps of tyvek accumulated from other jobs on my demoed sheathing because I knew it would be awhile before I would be able to side. I tore it down and ran rosin when I sided (cedar lap with cedar shingles for the corners). If you do not want to go through the trouble of pulling the tyvek just run rosin over it. Or better yet staple up newspapers over the tyvek. I remodeled a house that had that done for sheathing paper and it was fun reading the papers circa 1849. Seriously, I do not know of any adverse effect of running rosin over the tyvek, at least more so than tyvek alone. The rosin paper is unaffected by the cedar and because it absorbs moisture better than the wood, it will act as a blotter and disperse it for better evaporation.I have nothing against felt and sometimes use it for a starter course where standing moisture (ie snow) may be persistant, but I like rosin paper for the rest.I think that rosin because of it's porisity also allows the back side of wood siding to breath better, reducing the need for cedar breather or furring strips at least on shingles. I never bother with back-priming either. I use a good penetrating oil finish and have had nothing but good results.just some thoughtswalk gooddavid
*tim... in this climate the sidewall shingles don't get wet enough to stay wet.. so .. no rain screen..on the roof though, wood shingles that are not installed over skip sheathing or cedar breather.. stay wet on the back most of the year, creating conditions for accelerated deterioration.. so instead of a 30 year roof , you might get 15..the SS ring shank nails .. we use a Bostich N63, or N64.. sidewall col nailer with Bostich SS nails...
*George,Thanks for responding promptly to my question about shingles over Tyvek. Most of the responses were not good news. I already have most of the trim boards in place around the windows and doors, and the trim is 5/4 MDF, preprimed. If I do have to apply furring strips before shingling with western red cedar, could it be 1-inch-wide strips 1/4-inch thick? The 1x3 someone recommended would require alterations to all my doors and windows.This may sound like a really dumb question, but do I run these furring strips horizontally or vertically, and how far apart? Thanks!
*It looks to me that the 5/4 MDF is thick enough to accomodate furring strips without too much fuss. I don't know how ethical that is, but in your case I would rip 1/4" X 3" strips of plywood and nail them horizontally, one for every row of shingles. If you planned on a random layout, you will have to tighten things up a bit. You could also back prime the shingles and clean the edges on a sliding miter saw. You should also ask around for what other builders do in your region, for you might not really have a problem if the rain is minimal.fv
*I used mason's lath for furring strips on my house. Cost about $6/bundle at HD. Saves ripping, saves Doug fir for higher purposes and it rids the world of poplar scraps.Andy
*Is breather or furring needed under a product like shakertown or cedar valley panelized cedar shingles?Is it OK to still go with the Tyvek?
*I like david's suggestion the best. There is a cedar shingle job I sided 15 yrs. ago, no dipping, no backpriming, the guy gives it a coat or two of CWF about every 4 yrs. I drive by it at least 3 times a year and it still looks great. I think the key is the guyb maintains it. Something many homeowners ignore.John
*Chuck, you can use the Shakertown and Cedar Valley over tyvek... the Cedar Valley I've used has a 5/16" plywood backing which would be contacting the vapour barrier. It's the direct Cedar/Tyvek contact that needs to be avoided, wether by using Andy's patented Mason's Lathe... (I owe him royalties)... or by use of Cedar Breather.The panelized shingle products have a plywood, asphaltic fibreglass, cedar shingle layering.Fasten with S/S ring shanks... we use Hitachi N65 coil siding nailers.
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I have spent the last 7 months building my dream house, and I read in my latest FH that when cedar siding is applied over housewrap that water will leach tannins from the cedar and clog the pores of the housewrap, causing the siding paint to fail.
This is disheartening, because I have just wrapped thew whole house with Tyvek, and am planning to shingle over this (siding, not roof) with cedar shingles. Will the shingles do the same thing as Joseph Lstiburek described?
If it was cedar siding, I would backprime the boards as he recommended, but I don't want to paint the backside of the shingles because I want them natural on the outsaide and I'm worried about slopping primer around to the "good" side, especially after I'm on to the 20th bundle and gewtting careless.
What is a good way to preserve the look of the natural cedar shingles. I know they'll age, but I'd like the house to age gracefully. We are at 3500 foot elevation in Northern California, so we have hot summers and some snow in the winter.
Any suggestions? Jay Storer