# Ten Rules of Roof Desgin



## Martin Holladay (Dec 9, 2011)

Here are my Ten Rules of Roof Design:
1. Avoid valleys
2. Just say no to dormers and skylights
3. An unconditioned vented attic is better than an insulated roof
4. The best roof shape is a simple gable or hipped roof
5. Don't reduce the slope of your roof halfway between the ridge and the eave
6. Asphalt felt makes more sense than synthetic roof underlayment
7. Plumbing vent pipes should penetrate the roof near the ridge
8. Choose metal roofing or asphalt shingles
9. Get your flashing details right
10. Anticipate ice dams

More details are here:
http://www.greenbuildingadvisor.com/blogs/dept/musings/martin-s-ten-rules-roof-design


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## vtroofing (Sep 27, 2009)

bla bla bla someone shouldn't be roofing


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## shazapple (Dec 3, 2010)

After reading the article I'd have agree with all your points, except #8. If you are going to put metal on, an exposed fastener system is not the way to go. The neoprene gasket on the fastener is the weak spot in an otherwise long lasting roof.


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## Grumpy (Oct 29, 2008)

I can go into so many more details of what to avoid, but also could argue with many of your suggestions. Since you are most likely a spamming one hit wonder, it would be a waste of my time to go into detail other than to give a thumbs up to VT who said "Someone shouldn't be roofing" as he referred to you, Martin Holladay. 

Avoid dormers, skylights and valleys, why? 

BTW you should rename your thread to "sloped roof design".


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## shazapple (Dec 3, 2010)

I think the point he is trying to get at is that any projection in a roof is going to be a maintenance item or a weak spot. That is true, but avoid them? That would make for a boring building.


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## Billy Luttrell (May 3, 2010)

shazapple said:


> I think the point he is trying to get at is that any projection in a roof is going to be a maintenance item or a weak spot. That is true, but avoid them? That would make for a boring building.



Not to mention it would take away 80% or more of the reroofing market for you.


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## Grumpy (Oct 29, 2008)

I think the point he was trying to make was "spam my info so my site gets more back links and people read my chit and I get more money." 


You're right shazz, I agree, penetrations are weak points. That is why we as PROFESSIONALS need to take extra time and effor tand use only quality materials at these weak points. If the installer is a weak roofer, the weak points will leak. There is no reason to avoid dormers, and skylights. Heck what about plumbing pips, should we just vent the sewer gas into the attic and let the roof vents evacuate the stink? (I've seen this method with sewer pipes on additions by the way).


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## vtroofing (Sep 27, 2009)

Well this picture should make the OP cringe at the thought. 


https://www.facebook.com/photo.php?...68096633.82668.126933210658584&type=1&theater


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## 1985gt (Dec 21, 2010)

That is exactly why we don't do shingles. :laughing:


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## vtroofing (Sep 27, 2009)

It is roofed right, vented properly and well insulated, very well insulated so no worries there. Any later into the winter fat boy would be wearing more layers and wouldn't fit between the tails! 

An old farmhouse under vented and under insulated this design would be a concern.


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## NLshinglerBC (Nov 12, 2011)

lol it should be ten rules of metal roof design.
asphalt paper makes more sense then synthetic paper on metal roofs. yes....
not on shingle roofs
or ? lol nothing wrong with a bitta DECK ARMOUR.
in newfoundland, alot of contractors dont ask for any underlayment, just ol peel an stick cross da eave of er an in the valleyos. papers a bigger bluff then santa clause lol.
hands down http://bulldogroofing-ct.com/Documents/Deck Armor.pdf


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## shazapple (Dec 3, 2010)

I don't see the point of a breathable synthetic; it seems like a marketing gimmick. Asphalt shingles, as an assembly, have a very low permeance, so moisture still can't dry to the outside. If you have venting (which you always should) then it will dry to the venting.


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## Grumpy (Oct 29, 2008)

So shocked to see this nonsense thread go 2 pages. LOL, good discussion though.


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## Pie in the Sky (Dec 21, 2011)

shazapple said:


> I don't see the point of a breathable synthetic; it seems like a marketing gimmick. Asphalt shingles, as an assembly, have a very low permeance, so moisture still can't dry to the outside. If you have venting (which you always should) then it will dry to the venting.


Check out Page 12 in this months RCI Interface Magazinge. Your dead right and now there is testing to back it up.

I always liked synthetic underlayments when I roofed, their lighter, cover much faster, easier to walk on, can get wet... Just seems like a win win for the contractor that can sell it to his clients. I guess when your competing for jobs pennys can matter.


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## shazapple (Dec 3, 2010)

That is exactly where I got my info. It is an excellent magazine, although it would be nice if I could find an online source as well. I have a big stack of them I am reading through during the Christmas break.


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## Pie in the Sky (Dec 21, 2011)

PM sent... Not sure the etiquette for posting links in here.. If its ok I can post it for others who might be interested?


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