New roof on 160+ year old house

[Isaac Carlson]

We are replacing the roof on our old farmhouse. It was built in 1860. The original roof was wood shakes. The shakes were replaced with asphalt shingles in the 70's, from what we know, and that's what we are removing now. I want to put shakes back on it, but right now we have a stack of architectural shingles in the shed that we bought a while back, and they need to get used. I will split up shakes over the next few years and save them for the next time it needs replacing. The barn still has a shake roof, but it in need of replacement and it leaks in places. It is likely close to 100 years old, because nobody knows when it was put on.

The roof boards on the house are in great shape for being so old. Most were cut on a circular mill, but some were cut with a sash mill. We found the old saw blade, pulleys, belt, and shaft that were likely used to saw the boards, along with a stash of boards that were never used. We plan on using the stashed boards if they are still good, because there are a few boards that need replacing.

The beams in the basement are hand hewn pine, and the floorboards are circle milled.

 

[peakbagger]

Looks like a well built old structure. If it was mine, I would spend the bucks and put down Grace ice and water shield top to bottom and it will last far longer than you and I will be around. At a minimum do two rows at the bottom edge. No worries about ice damming and if you ever decide to do solar it seals around any new hardware. If you are DIYing, the water shield is good for sun exposure for several months so you can take your time on the roof and not worry about rain. Its pretty much the standard in my area for commercial and many higher end roofs as there are no callbacks for roof leaks. BTW if you were to go with steel roofing, there is a high temp ice and water shield that should be used due to the higher roof temp.

In some areas, if the roof boards are wide and thick, they will be removed and replaced with new sheathing, then the boards will be reused in a more visible location.

 

[Riverbanks]

Check out Cedar Breather underlayment

 

[Ashful]

Interesting photo. My house also has cedar shake under a "modern" roof. I don't know the age of the shakes, that part of the house is a 275 year old addition atop a 290 year old lower structure, but I'd be surprised if the shakes are that old.

What's interesting about your photo to me is the complete planking under the shakes. I have spent a lifetime in old houses, old church buildings, old barns, etc., and I have literally never seen one with full planking beneath cedar shakes. In fact, if you had asked me prior to seeing this, I'd have guessed that planking might even interrupt the surface tension that makes a cedar shake roof work, as I'm sure we've all seen the way a water droplet can find its way to the bottom side of the gap between two shakes, only to be ejected back outside by the one below them.

Cedar shakes around here are normally installed on purlins, the spacing of which matches the reveal on the shakes. The purlins are normally oak or other very strong hardwood, to endure snow load and foot traffic when spanning rafters on 24" centers, and most typically full rough 1x2.

One thing that would be another surprise to folks used to modern construction, is how small old roof rafters are by comparison to modern lumber. Most are only 2x6 rather than today's more common 2x10, even for very long spans, but full rough dimensions rather than modern S4S dimensional. I believe they get away with this due to a combination of four factors:

1. High pitch roofs, which both change the nature of the loading, and also reduce potential for high snow loads.
2. The old-growth from which these rafters were made was a better quality, both fewer imperfections and higher density of growth rings. I suspect most modern rafters are only No.2 grade?
3. Use of collar ties and knee braces was standard. I may have 2x6x21' rafters spanning 15' horizontal, but they have a knee brace at 1/3 length and a collar tie at 2/3 length. This helps distribute any mid-span loading to attic floor joists and into lengthwise compressive force on opposite rafter. I believe the same methods are used for modern engineered truss roofs.

 

[Gearhead660]

Our old farm house was built in the 1890s. I installed a standing seam metal roof about 6 years ago. What I found during the tear off was 3 layers of asphalt shingles and cedar shake under that. I also found complete planking. I attached a pic from one of the cedar shakes.

 

[Ashful]

Cool!

One of the houses we owned was built in 1865, and the carriage barn and shed in the back yard were completely wall-papered in old tobacco posters, maps, box lids... you name it. Just to see if they were worth anything, we removed a half dozen (of the many hundreds), and sent them to auction with some other items. Each poster and map sold between $100 and $600 dollars. So, it appeared we were sitting on a few $100k of these things.

A few weeks later my mom went back to start the process of removing several more, to find a tenant to which she was renting the place did her the "favor of pulling down and throwing away all those dirty old posters."

 

[Isaac Carlson]

Oh no!

 

[Tonty]

One thing that would be another surprise to folks used to modern construction, is how small old roof rafters are by comparison to modern lumber. Most are only 2x6 rather than today's more common 2x10, even for very long spans, but full rough dimensions rather than modern S4S dimensional.

What amazes me is going into the old gambrel roofed barns and seeing their roof framing. Often no ridge pole, some have no knee bracing, and sometimes what would count as the bottom cord or tie (in this case it would be the hayloft floor) isn’t even one piece. But yet they’ve stood for many years.
I love old barns, but we don’t have enough in this country. There are a few, but not near as many as when I go visit my sister in Ohio. I built our house to look like one, with a gambrel roof, but I didn’t emulate the no ridge pole or knee brace thing. I used a truss design where the inside pitches are slightly less than the outside pitch, giving room for more of a truss design.

 

[Ashful]

If you believe most code enforcement officers, none the 200+ year old houses and barns that dot my part of the country should've remained standing for even one year. Yet, here they are...

I actually had an argument about copying the floor joist pattern in one part of my house, into new work on another part of the house. The same joists that have been here and supporting who-know's-what since 1775, are apparently not safe by today's standards.

Unfortunately, neither of us will be here in 250 years, for me to show him that my proposal would hold up better over that period of time, than any modern construction.