shake roof/ no drip edge - InspectionNews

Jerome W. Young · #1 (**permalink**) 11-20-2008, 05:25 AM

Florida house
no drip edge metal; 24 in shake with 10 in. exposure; felt paper layered at each row of shakes; 5/8 plywood decking.

my question is the amount of overhang of the shakes at the rakes and eaves? as far as i know edge metal is not a requirement?

Raymond Wand · #2 (**permalink**) 11-20-2008, 06:21 AM

In my opinion and geographic location, I have never seen a drip edge on shake roof. There is plenty of overhang.

Cheers,

Scott Patterson · #3 (**permalink**) 11-20-2008, 07:03 AM

Quote:

Originally Posted by Jerome W. Young

Florida house
no drip edge metal; 24 in shake with 10 in. exposure; felt paper layered at each row of shakes; 5/8 plywood decking.

my question is the amount of overhang of the shakes at the rakes and eaves? as far as i know edge metal is not a requirement?

Well for one thing a 10" exposure is wrong. Depending on the grade of shingle and the slope of the roof you should not have more than a 71/2" exposure on a 24" shake.

The main purpose of a metal drip edge is to support the shingles so that the water "drips" off the edge. We have all seen roofs without a metal drip edge and how those composition shingles droop and the water then runs down the fascia, etc. With shake shingles they don't need this type of support, they are not flexible like a composition shingle.

In FL, you might have a requirement for a metal drip edge as this is part of the wind resistance system for the room.

Jerome W. Young · #4 (**permalink**) 11-20-2008, 07:31 AM

Scott
thanks

24 in = 10 in. exposure according to what i have researched
18in= 7in exposure

Raymond Wand · #5 (**permalink**) 11-20-2008, 07:37 AM

The species and type of wood and thickness composing the shake roof will also factor in as to exposure. Is this shake or simply wood shingles?

The fact the wood shingles are laid on plywood decking will shorten the life in half.

David Banks · #6 (**permalink**) 11-20-2008, 09:33 AM

Quote:

Originally Posted by Raymond Wand

The species and type of wood and thickness composing the shake roof will also factor in as to exposure. Is this shake or simply wood shingles?

The fact the wood shingles are laid on plywood decking will shorten the life in half.

I would think the sun in Florida would shorten the life in half? Maybe down to one quarter.

Raymond Wand · #7 (**permalink**) 11-20-2008, 09:40 AM

I understand that some insurers are also kicking up a fuss about wood roofs due to fire issues?

Jerry Peck · #8 (**permalink**) 11-20-2008, 12:25 PM

Quote:

Originally Posted by Jerome W. Young

24 in = 10 in. exposure according to what i have researched
18in= 7in exposure

Depends on the wood species.

From the 2004 FBC-Residential, Table R905.8.6

Shakes of naturally durable wood - 24" length, No. 1 grade = 10" exposure
Shakes of naturally durable wood - 24" length, No. 1 grade = 7-1/2" exposure for 3/8" hand split shakes

Preservative-treated taper sawn shakes of SYP - 24" length, No. 1 grade = 10" exposure
Preservative-treated taper sawn shakes of SYP - 24" length, No. 2 grade = 7-1/2" exposure

Taper-sawn shakes of naturally durable wood - 24" length, No. 1 grade = 10" exposure
Taper-sawn shakes of naturally durable wood - 24" length, No. 2 grade = 7-1/2" exposure

Wood shingles are another matter, with 24" shingles having an allowed exposure between 5" (No. 3 grade) to 5-1/2" (No. 2 grade) to 5-3/4" (No. 1 grade) on 3/12 to >4/12 slopes, and an allowed exposure between 5-1/2" (No. 3 grade) to 6-1/2" (No. 2 grade) to 7-1/2" (No. 1 grade) on 4/12 and greater slopes.

Quote:

Originally Posted by Raymond Wand

The species and type of wood and thickness composing the shake roof will also factor in as to exposure. Is this shake or simply wood shingles?

Correct - see above table.

Quote:

The fact the wood shingles are laid on plywood decking will shorten the life in half.

In Florida, most of Florida requires solid sheathing, structural panel sheathing, for sufficient strength to resist the wind loading from those high wind events Florida gets.

Not sure if it reduces the life of them or not.

Quote:

Originally Posted by David Banks

I would think the sun in Florida would shorten the life in half? Maybe down to one quarter.

Maybe even less than 1/4. The sun really kills them in South Florida. Jerome is just north of the north end of what is considered 'South Florida', the sun is not as brutal there, but I would still imagine a greatly reduced life expectancy, maybe reduced by half.

Wood shingles and shakes are definitely NOT the best choice for roofing material in Florida, especially in the southern half of the state, and critically so in the lower 1/4 of the state. Florida spans from Tropical to Temperate zones with the lower Keys being in the Tropical Zone, South Florida being in the Sub-Tropical zone, North Florida being in the Temperate Zone, and Central Florida spanning the vague change over from Sub-Tropical to Temperate.

Wood shingles and shakes may do well in North Florida, they do very poorly in South Florida, and mixed results between the two - Jerome inspects around where the north end of South Florida and the south end of Central Florida meet.

Back to the drip edge, or lack thereof ...

Unless it is stated in the manufacturer's installation instructions, I don't see it in the code, however, those manufacturer's installation instructions would need to be approved for the wind speed zone you are in, which would 'most likely be' either 130 mph or 140 mph. I'm not sure that wood shingles or shakes are rated and approved for those wind speeds. You would need to check the product approvals on them.

Nothing is easy in Florida, is it?

Raymond Wand · #9 (**permalink**) 11-20-2008, 12:57 PM

What a waste of resources not to mention the cost.

For wood shingles to last, they have to breath. If placed on plywood sheathing they never dry out as well as those placed on purlins which allow the two sides to dry equally. However considering Florida is hurricane territory I can see the reason for solid sheathing.

Also the steeper the roof pitch the greater the exposure can be.

Scott Patterson · #10 (**permalink**) 11-20-2008, 05:06 PM

I'm for a Thatched Roof! Now that would be fun in Florida!

Might work well in some parts of the country. Heck, they have worked well in many parts of Europe for hundreds of years!

Jim Robinson · #11 (**permalink**) 11-20-2008, 05:41 PM

Like this one? It must take a while to learn how to do this.

Vern Heiler · #12 (**permalink**) 11-20-2008, 06:17 PM

Quote:

Originally Posted by Jim Robinson

Like this one? It must take a while to learn how to do this.

When houses had thatched roofs, thick straw-piled high, with no wood underneath. It was the only place for animals to get warm, so all the cats and other small animals (mice, bugs) lived in the roof. When it rained it became slippery and sometimes the animals would slip and fall off the roof. Hence the saying . It's raining cats and dogs.

Richard Pultar · #13 (**permalink**) 11-20-2008, 10:40 PM

Thatched roofs are a perfect example of how the blind allegiance to almighty code is over kill. If you don't like like the idea that the roof is not code proper don't buy the house. For the code to prohibit such a wonderful roof is a shame.

Ken Amelin · #14 (**permalink**) 11-21-2008, 06:14 AM

When installing wood shingles or shakes over plywood use a breather underlayment. Example of one type of alternative system

Cedar Breather Underlayment from Benjamin Obdyke

Christopher Gorton · #15 (**permalink**) 11-21-2008, 07:19 AM

Direct from the cedar council on the installation of cedar shingles is, use no field underlayment. This is on a new home in the south east US
Mount it straight to the plywood with a run of paper over the eaves and one up the rake.
I looked at that breather product as well, before I contacted the cedar representatives, as it seemed to make sense to keep some kind of airflow underneath the wood. The install directions said no.
I would imagine there are very specific nailing patterns for higher wind zones, if that is in fact an acceptable roof covering at all in those areas.

Jerry Peck · #16 (**permalink**) 11-21-2008, 01:29 PM

Quote:

Originally Posted by Richard Pultar

Thatched roofs are a perfect example of how the blind allegiance to almighty code is over kill. If you don't like like the idea that the roof is not code proper don't buy the house. For the code to prohibit such a wonderful roof is a shame.

Richard,

I find it hard that a home inspector says the things you do.

I can only imagine the houses your clients buy and the condition they are likely in.

It is a disgrace to the home inspection profession to have such an attitude.

Ken Amelin · #17 (**permalink**) 11-21-2008, 03:41 PM

Jerry,

I'm not sure what code thatched roofs violate???

We have a large retail store with a wonderful thatched roof. The owner flew tradespeople from Ireland along with thatching for this project. It was built approx. 7+/- years ago. There was no problem building this one.

Jerry Peck · #18 (**permalink**) 11-21-2008, 05:49 PM

Ken,

This was the part of Richard's post I was referring to. He has made a few posts with the same 'screw the code, do what you want' attitude.

Quote:

Originally Posted by Richard Pultar

allegiance to almighty code is over kill.

In one electrical post he suggested something truly absurd, which I do not remember right now.

Quote:

Originally Posted by Ken Amelin

I'm not sure what code thatched roofs violate???

Basically all code sections except this one:
From the 2006 IBC. (not posting the entire sections)

- 104.11 Alternative materials, design and methods of construction and equipment.

- - 104.11.1 Research reports.
- - 104.11.2 Tests.

If the above is followed, then it "meets code" without actually "meeting code".

christopher bittner · #19 (**permalink**) 11-21-2008, 06:31 PM

to all: those thatched roofs are splendid indeed. I don't
think that there is any issue with the roof and and as Richard said if the client likes it why not. I do some simple quick homework for the client. Simple. All this stuff is not that complicated. Wood shingles use a starter course which is suitable and durable without need for a drip edge. ( they been putin' em up along time before i was around). A rake moulding can be installed on what appears to be a 1x10 rake. Often a simple piece of 1x2. Other mouldings are more pleasing to the eye- My favorite is "Whale Back".
My friend from Cap Cod certainly has an idea about Mass. requirements for shingled roofs as well as my friend from Canada. Chris Bittner

Jerry McCarthy · #20 (**permalink**) 11-23-2008, 10:42 AM

RE: wood shake roof covering. I have never figured out why anyone in their right mind would have kindling installed on their roof tops? Many of our local jurisdictions have outlawed such by passing city ordinances. Thatched roofs? I'm not even going there.

Jerry Peck · #21 (**permalink**) 11-23-2008, 03:49 PM

Quote:

Originally Posted by Jerry McCarthy

RE: wood shake roof covering. I have never figured out why anyone in their right mind would have kindling installed on their roof tops?

Thatched roofs? I'm not even going there.

WC Jerry,

Well, apparently several inspectors here think that thatched roofs are okay ...

... I look at thatched roofs as the 'easily ignitable matter' used to light off your kindling wood shake roofs.

First, you get a spark glowing in the 'easily ignitable matter', then blow on it until it becomes a flame, then add some kindling ...

Ken Amelin · #22 (**permalink**) 11-23-2008, 05:26 PM

Quote:

Originally Posted by Jerry McCarthy

RE: wood shake roof covering. I have never figured out why anyone in their right mind would have kindling installed on their roof tops? Many of our local jurisdictions have outlawed such by passing city ordinances. Thatched roofs? I'm not even going there.

[color=#000080]

Quote:

Originally Posted by [/COLOR

Jerry Peck]Well, apparently several inspectors here think that thatched roofs are okay ...

... I look at thatched roofs as the 'easily ignitable matter' used to light off your kindling wood shake roofs.

First, you get a spark glowing in the 'easily ignitable matter', then blow on it until it becomes a flame, then add some kindling ...

To the Jerry's - What are you both thinking about???
I agree that thatched roofs are a thing of the past, but wood roofs are here to stay. They've been around for century's. They are durable, energy efficient, have visual appeal and they are green.

DO YOU THINK THAT ASPHALT ROOF ARE LESS FLAMMABLE??? -- HELLO!!

or are you both just trying to pass the time away and complain about something?

Come on now folks.

Ted Menelly · #23 (**permalink**) 11-23-2008, 06:46 PM

Interior and exterior sprinklers, no problemo. Well, maybe a little bug killer would be in order

Can you see all those wonderfull big roaches and tree rats living in them.

Jerry Peck · #24 (**permalink**) 11-23-2008, 07:56 PM

Quote:

Originally Posted by Ken Amelin

I agree that thatched roofs are a thing of the past, but wood roofs are here to stay. They've been around for century's.

Thatched roofs and mud huts have been around longer than wood roofs ... what is your problem with them, why are you not saying that "They've been around for century's." and that they "are here to stay"?

Surely you are not deriding one very old method which has been around longer (thatched roofs) to justify accepting a much younger and newer roofing method (wood shake) ... are you?

Also, in case you have not read the posts above, wood roofs *DO NOT LAST* long in some environments, such as South Florida.

Yes, asphalt shingle roofs burn, but they do not ignite as quickly, and go up as quickly, as wood and thatched roofs do. Then again, most roofing materials burn, heck, get a concrete tile roof hot enough and the underlayment will burn, same with metal roofs.

In case you have not noticed, we has s-t-r-a-y-e-d w-a-y off the topic as posted.

Frank Suchodolski · #25 (**permalink**) 12-05-2008, 06:26 PM

[quote=Scott Patterson;63042]Well for one thing a 10" exposure is wrong. Depending on the grade of shingle and the slope of the roof you should not have more than a 71/2" exposure on a 24" shake.

7 1/2" exposure on 24" cedar "shingle" and 10" exposure on 24" cedar "shake", that's up here in the Great White North anyway.