# New roof on my own house



## shazapple (Dec 3, 2010)

My house is over 100 years old, and currently has corrugated metal over asphalt shingles over wood shingles over a board deck. The house is a 1.5 story, meaning that the upstairs has sloped ceiling and a small attic space. The previous owner has insulated the sloped ceiling directly under the roof deck (aka no insulation). 

I'm putting an addition on, and I plan on replacing the main roof at the same time. I'm at the point where I'm tying into the existing rafters, I've stripped off the 3 layers of roofing, and the existing boards are crap. There are many areas of rot and the top layer turns to dust if you look at it wrong. 

Here is my plan: Remove the 3 layers of roofing, leave the boards, strap the roof to provide an airspace and then apply new plywood. I would place strapping over top of the rafters (31" OC, strangely enough) as well as 24" OC. The strapping over the rafters gives the new plywood something to hold and the 24" supports the ends. 

From there I'll put down underlay and metal roofing. Any comments or suggestions?


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## vtroofing (Sep 27, 2009)

What is your hemispheric location? Energy savings is an obvious thought to add insulation, airspace created with your strapping will help comply with your shingle manufacturer specs- but what about actual bettering your home by adding real insulation value that you will feel? 
Just my thoughts... here in Vermont comfort the next few months are key!


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## Grumpy (Oct 29, 2008)

Not sure about tying the new structure into the straps, but this is what we call a false deck and is a great idea for ventilation. Personally I would tie my new framing into the existing framing so the straps won't carry load. You could also install a vented nail base such as Atlas cross vent AC, but again wouldn't dare tie into that product for structure. Some of the vented nail bases offer insulation as well as ventilation.


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## shazapple (Dec 3, 2010)

I thought about putting rigid insulation down, but there's a problem. The lower half of the rafters are part of the sloped ceiling of a interior finished space, but the upper half of the rafters face a typical attic. Insulation on the lower half works but insulation on the upper half would be a waste of money. It seems difficult to strap the upper half to match the thickness of the lower half?

Grumpy, I've removed everything down to the rafters where I am tying in, so the new roof trusses will tie directly into the existing rafters. Then I will sheath the new addition, and then install strapping/plywood on the original.


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## vtroofing (Sep 27, 2009)

Spray foam... at about $1.00 +/- per board foot R is around 7 per inch. I see the Canada now. More is better.


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## Grumpy (Oct 29, 2008)

In this case the ceilings are already insulated, VT. Did I read that right shazz? Sure more insulation is often better, but does limit or void some shingle manufacturer warranties, and for very good reason. All the shingle roof warm deck designs I have seen have been premature failures. 

You can have more ventilation and more insulation with the product I mentioned, the Atlas Cross Vent AC. If I were happy with the insulation I already had, I would just strap it like Shazz said. Regardless though, with an asphalt based shingle I would want some kind of ventilation.


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## carlwatson (Nov 3, 2012)

In my opinion putting metal roof may heat up our roof a bit but if you are residing in a area where the climate is cold then its perfect to place a metal roofing. Also if it rains a lot in your area, then try installing gutter cover, which will help you to get rid of the unwanted water.


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## Ditizan (Jan 8, 2013)

If possible, expand the abbreviation "OC" (I can not fully understand the text in translation). Sorry for dullness, but a very interesting case of home repair 100 years of age.


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## shazapple (Dec 3, 2010)

OC = On Centre. Example: my wall studs are 16 inches OC, meaning the centre of one stud is 16 inches away from to the centre of the next stud. 

We ended up removing all the old layers, laying down sythetic underlay, strapping, and then a metal roof. The sloped ceilings in the original house are still under insulated/ventilated so I'll have to work on that from the inside. 







That picture was taken the day the roofer finished. He procrastinated on installing the ridge cap and the snow bit him in the ass. He got it done though. 

As for the addition, the trusses have almost 16" of space, so with the vent baffles I'll have plenty of insulation.


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

looks good! Alot you can do with that!

D


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## brianshaw (Jan 21, 2013)

Hey now that house looks great and no one can say that its more than 100 years old, keep on sharing more images from the interior.


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## OldPro (Nov 11, 2013)

Great property! Enjoy your newly useful space!


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