I have a client with a cedar shake (not shingles but thick shakes) roof. Ranch house, low slope 3 or 4 pitch. They replaced this roof with same about 10 years ago.
Didn’t dig into specifics, but I believe the shakes are applied over solid or skip sheathing–eaves are ply–with 30lb felt as I have seen others in the area.
Their problem is the house has an integrated gutter boxed in on top of the rafter tails that is leaky and starting to rot the sheeting and some rafter tail tops…
I proposed to rip the integrated gutter off, sheath down, plumb cut the rafter tails, install fascia, roof down to it and put regular continuous gutters on the house.
What sort of longevity can be expected in Pacific Northwest for the existing cedar shake roof on such a shallow slope?
opinions welcome, thank you.
Replies
I'm not sure about the PNW but I hate to see shakes on less than a 5/12
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
In 1977 the first subdivision went in near me, pretty good sub as they left most the big fir. One 'fancy' feature was they all had cedar shake roofs, mostly 7/12, some steeper.
Over 80% of the houses (now mostly $6-700K type) have had the shakes replaced, the other 20% have had quite a few repairs and numerous shingles replaced. The few 5/12 roofs ALL have composition or tile or metal roofs now.
So, say a 50 percentile life for my guess when the replacement hit 50% was the late 1990s, so say 20 years under fir trees, probably longer for no trees in what sunlight there is. Many folks pressure wash their roof bi-annually.
Own roof is composition 3/12 double selvage, under heavy fir trees, I clean it off twice a year. 4 inches wide of zinc on each side to keep the moss down.
Hope that helps.
I concur 100%. When I saw the original post, my immediate thought was 20 years.
The parents of a friend of mine recently had their heavy shake roof replaced after 30 years....it was old growth Redwood.
Shake roofs may be charming, but the longevity, coupled with the maintenance, they're being a fire hazard and a corridor for infestation of carpenter ants, bats, etc.... regardless of the pitch, I'd opt for more proven materials.
I'll also note that the shakes one purchases today are often from younger and less rot resistant wood and the life expectancy is much lower.
Thanks gents.
I think these folks would be better off to limp along a while longer, replace the whole roof--i'd do metal if it were mine--and swap out the integrated gutter BS for conventional fascia and gutter at that time.
While describing the cons to their low-slope shake roof and their leaky integrated gutters I was asked point blank why the house was built this way... I stammered a few things... perhaps customer drove the design, perhaps integrated gutters were a local fad for this builder...
I do know this... bad idea for this area! It's too bad when the previous shake roof went they replaced with like.
Cheers,
pat
Depending on site conditions , and the initial quality of the shakes 15-20 yrs.
"Poor is not the person who has too little, but the person who craves more."...Seneca
MY folks had their cedar shakes replaced a year ago, original on the house from 64'. That said, they were undoubtdly better cedar than what was available 10 years ago, and, if they'd replaced the things 20 years ago, there wouldn't be 4 ceiling patches from the leaks they had to have fixed.
lifespan, 20 years. Unless your willing to really work at it.
edited to add: 30 miles north of Seattle
Edited 7/3/2007 6:49 pm ET by deskguy
You didn't mention if this was a shady side or not and if moss was a problem?
I would recommend having the roof pressure washes every so often and installing a zinc strip along the ridge line.
With a fresh wash you can re treat the roof to restore the natural oils in the wood that can help in preventing rot.
and the zinc strip can attract the moss if that is a problem.
I have seen roofs that have been maintained to last easily 20 years.
Hope this can help.
Well, if you want a really long lasting cedar roof, consider this:
Down the road from me a couple of miles is a farmhouse that is about 100+ years old (which is an exception here on the Oregon coast).
I became friends with the last of a family who had pioneered there and this old man had been born in the house.....he died at age 96 about four years ago.
He swore to me that the shingles (shingles, not shakes) were the original and the reason that they lasted so long was that every year his ancestors and then he sprayed the roof with used motor oil cut with diesel.
Now, I can't verify his claims, but I do know that his house always smelled like an old garage and the shingles did look tight and in decent shape.
I always wondered, though, how fast that house would disappear if a fire broke out.
notchman,
I had a neighbor who used a treatment a bit like that on barn posts He built a barn back in the early forties. Sank DF poles in the ground for the posts, then drilled a 3/4" hole into the posts at a slight downward angle until he hit the center of the post. Did this at two locations about 180 deg. from each other.
Used his old motor oil and cut with kerosene to fill a soda pop bottle and stuffed it into the hole. Refilled it when it went dry. I was in that barn in the late 90's and the posts were still solid.
"Poor is not the person who has too little, but the person who craves more."...Seneca
I'm betting there was some lead in the used motor oils that was toxic to the micro-orgasisms, so the kero was a carrier, the heavier oils repelled water,and the lead particles did the heavy work as armed gaurds. You won't find lead in the used motor oil today.But you can buy ccopper to inject like that.I wonder if auto parts stores still have lead additive on the shelves....
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Pif,
Might be wrong, and I don't have a bottle here to inspect, but I've heard that "lead additive" these days doesn't actually contain lead. Some say "snake oil."Todd
I'd believe it!
The shingles on my 30's craftsman have 1 or 2 sets of old nails hammererd flat under them. I think this is the second or maybe 3rd roof. Gettin' pretty crusty but no leaks!
Thx,
Treat your roof or your barn posts like that enough and pretty soon your property is a Superfund site. I'd hate to see an analysis of the soil near that house.
I think that if soil samples were taken from a LOT of old farms across America, a majority would have some serious soil contamination problems.
However, I was involved in some pending Superfund issues with a past corporate employer, and the threshhold for achieving Superfund status is pretty high and I doubt a small farmstead could achieve such soil polution levels unless the farmer was permitting illegal disposal of toxics on his property in large volumes.
There's a shooting "club" not far from here, in a low-lying wetland area, and apparently the amount of lead lying around has caused an amazing amount of soil contamination. It all runs into the Strait of Juan de Fuca from there.
Well, I have seen wood roofs last fifty years.
That was in dryer climates and with paint on the shingles instead of oil treatments."you can re treat the roof to restore the natural oils in the wood that can help in preventing rot."the way you express that is more mythological than fact based.
treating can certainly help, but not in the way you are saying.The reasonn tht cedar is rot resistant is thaat it contains natural preservaative oils INSIDE eah individual wood cell.
Once a cell is opened from sawing, sanding, or UV breakdown ( or even careless pressure washing) the oil is lost quickly. if you spray oil out of a can onto the surface, it is far from the same thing as the oil that was inside the wood cells, definitely not "restoring the natural oils"What the new oil is doing is repelling moisture on the shingle surface while the natural oil is repelling it from entering the individual cells of the wood. Also, the natural has tannins that are unfriendly to micro-organisms that cause rot. Unlesss you use a surface oil that has chemical additives to do the same, it does little to stop the surface growth
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
sometimes people scare me the lead guys are talking about in older fuel is called "tetraethyl lead" and is a contact poison make enough wet or vapor contact with it during the job, or quickly in concentration, and you won't have to worry about the roof or anything else don't look for it don't touch it don't use it ifn environmental agency finds out you're using that stuff anywhere, u can probably still access Breaktime from the prison library if they got a computer
if u use a wood roof u lose your "class A fire rating" on homeowners insurance and rates go up can't lie about what kinda roof is on the house, might invalidate insurance can use a fireproofing application periodically on the roof to regain "A" fire coverage, not worth the effort ifn u go w wood roof, use zinc flashing halfway up the roof, then again at the ridge really cuts microorganism growth, used to do this on regular roofs in forested areas to prevent staining and growth of lichens, moss etc. adds a few years to roof