I’m not a roofer by no means…but have always heard cedar shakes need to breath.
How do they breath on a regular plywood roof?
The gambrel house we just did and this new club house will be cedar shaked….we’re not doing the roof, just curious.
BTW, the builder uses that synthetic roofing material and not felt.
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Replies
I believe that you can put treated wood shakes over solid sheathing. http://www.cedarbureau.org/installation/roof_manual/page03.htm#
I would recommend a drainage mat. Here is one from dryvit. http://www.dryvit.com/files/dryvit_docs/us/description/ds446.pdf
There are others as well. Ask your local roof supplier.
The skip sheathing was designed to let air dry the shakes out. I believe that just adding treatment to the shakes does not qualify as a method of installing shakes over solid sheathing.
But what do I know.
Wood is Good
Adam Greisz
We have a development in town where white cedar roofing was a required architectural element. It wasn't a common roofing material for most of the builders and they handled it like they would with side wall applications. Many of the roofs started to fail within 10 years. The shingles were applied over 15# felt that was applied to the plywood roof sheathing. Several issues probably contributed to the early failure. One was that the shingles were fitted tight to each other, without spacing. Attics were not vented correctly, causing ice dams and moisture got trapped on the back side of the shingles. Not many of the homes in this development still have the cedar roofs. The "rule" is no longer. Wood roofs aren't very popular in an area where most folks use wood stoves for back up heat.
Today, most of the new cedar roofs have a cedar breather under them. Some builders are using it on side walls also. It is a woven mat like material that comes in a roll. I haven't used it but I haven't done a wood roof in many years either. We didn't have bituthane back then and builders are using proper insulation and ventilation today. A natural cedar roof will get plenty wet and needs to be able to dry out. Whether the shingles are installed on furring strips or with this relatively new material, I think allowing the shingles to breathe is important. There is additional info on the site below about wood roofs, the difference between shingles and shakes as well as various products and treatments.
http://www.woodroof.com/item120.htm
he asked about shakes and you are replying about shingles. They are two different animals witrh two different installation methods.
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There is often confusion about the difference between shakes and shingles. Sometimes it's just local vernacular. That's why I included a web site that explains the difference. There isn't a heck of a lot of difference in installation though. They are both pieces of wood that are attached in a row, side by each. Either can be applied over solid, skip sheathing or furring. Either can be interlaced with felt, or not. There is also the sidewall product that are called shakes but look like wide shingles and are installed with the celotex backer. They come in a box and are primed. Of course there are hand splits, hand split and re-sawn, 1/2", taper sawn, hand tapered, mediums, heavies, jumbos and fancy butts, all available in different lengths. There are also different grades available and there is a difference between red cedar and white. You have Blue label, premiums, No. 1s, No. 2s, Red labels, add in the whites with clears, extra clears, Cs. There are also different species such as yellow cedar, which is actually a cypress, and even oak and pine. Anytime you are talking about shakes or shingles you have to use the entire name in order to be clear about the product. If someone were to say, Yellow cedar #1 premium grade 18"x5/8" taper sawn shakes Certisawn 100% edge grain Blue label, we would know specifically what product they were talking about. Add to that the installation method, roof pitch and exposure. Just to add a little more confusion, the products can also be air dried, green, kiln dried, pressure treated and/or fire retardant treated. There isn't another roofing material that is as attractive a wood roof in my opinion. I enjoyed watching the roof shinglers at Williamsburg. They hand split the shakes, tapered them with a draw knife, cut them to width and shaped the butts. They installed them with wooden pegs, holes for the pegs were burned in with a hot poker that was carried in a bucket of coal. Talk about labor intensive work. One of the the things about wood roofs is their longevity. Even the best, thick, hand splits have a life expectancy of 20 years. Many roofs out live this expectancy but many more fall victim to fungus, mold, moss, ice and snow, storms and of course, fire. Whether you are talking about natural shakes or shingles, they will get wet. If the face surface dries out ahead of the back side, you get cupping. Once cupping occurs, weather can find it's way in more easily. I'd recommend using an installation technique that allows the product to breathe.Beat it to fit / Paint it to match
That dissertation showed you to be fairly familiar with wood roofs, but I still disagree strongly with you on this statement, "There isn't a heck of a lot of difference in installation though."There really is a lot of difference. Shakes are laid generally with a double ply and a 20% headlap. Shingles are generally laid triple ply with the same percentage of headdlap.Then the shingles are laid fairly close together while shakes get their breathing room from the wider gaps, and irregular shapes.Shakes are ahnd split so have a smooth surface that facilitates shedding water wqhile shingles have a sawn surface that facilitates wicking water up. These three basic differences account for the differences in installation technique. Shakes get help from interwoven felt to shed water because of the wide gaps, while shingles need more help breathing to dry evenly. The biggest common denominator is that nail heads should not be driven to deeply
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I don't see many roofs with either, but in my area, cedar shakes applied over plywood don't seem to last more than 15 years or so, but in the few developments where they used them, they didn't interleave them either.So I don't know if it is the solid substrate or the lack of interweaving or possible low grade material.What ever happened to skip sheathing?We know skip sheathing works, and yet the "air space" mats are the "solution" advanced for a problem that was solved a few(?) centuries ago.
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hammer.....<<<<that are attached in a row, side by each>>>>
"side-by-each".... are you from Pawtucket ?....
didn't know anyone outside of Rhode Island to use the termMike Smith Rhode Island : Design / Build / Repair / Restore
"side by each". I thought that was a Maine term, Mike. I'm not from Pawtucket but I should be an honorary Rhode Islander, since my youngest just graduated from Roger Williams University. The "Ocean State" is my second favorite New England state. I hope some of my contribution made it your way.Beat it to fit / Paint it to match
hammer... wher i got of the army in '69 i went to Roger Williams.. the business school was in Providenceon Pine Street....
in an old church.. some of the classes were in the YMCA
i took Construction Technology...
anyways... the Liberal Arts were out in Bristol , where they are now.. but they wouldn't let the grunts from business trespass until about 10 years later..
now they have a school of Architecture & Law... really made a sucess out of that school
keep saving your money... the kids will be back to tap you for something else, don't worry
Mike Smith Rhode Island : Design / Build / Repair / Restore
i've heard the olde timers up here use that phrase
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shakes are 3/4" thick with about a hlaf inch space betwen them. Being hand split, they have penty of irregularity to allow aitr in for breathing
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