Author Topic: Cabin Roof  (Read 389 times)

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Offline fcpnorman

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Cabin Roof
« on: November 23, 2017, 12:44:57 PM »


Hello- I have posted here in the past- I owned a great piece of property in Northern California near Mt. Shasta. I was planning on building a cabin that would have been off the grid. The problem was that I was not the only person who liked the area- apparently so did a whole bunch of dope growers. Was not really into being surrounded by grows- so I ended up selling to one of them.
I stumbled onto a great little cabin not far from there- with no dope grows around it... It is a fixer- and I knew that going into it. We bought it "as is". I did all the inspections myself and knew all the issues as we went forward. I have been working away at it-and it is probably more my speed than building off the grid( my hat is off to all you have have built so many great places that I see on here).
Primary issue I am dealing with is a roof issue. The design was poor- the cabin is an A-Frame with a flat roof attached. The flat roof section is 18x32. The roof has 16 inch overhang and is a series of 2x8's separated and run parallel to each other to form a beam. The roof is 2x6 T&G. I am furring out the ceilings and adding recessed lights and insulation.
The roof covering on the flat roof is fiberglass fabric with some type of tar mopped on. It has 0 slope.... So it holds water that then freezes. I have leaks right along the section where the two roofs meet.
I put on two coats of Gacoflex roof coating($$). It worked fine for one year, but has now leaked again.
My long term plan is to build a new roof over the existing and extend it up the pitch of the A-Frame to get a 4:12.
Thinking of looking into having trusses built that I could put in place- might be faster. The other option is to build in place- but I think I would need to add a purlin to support that 18-20 foot run.
I think I probably need to cut the eaves back- so all the load is lined up with the exterior bearing walls? I know the county will require engineering- but looking for some thoughts.
Short term I put henry's down and am looking at doing a patch with perhaps a section of roll-on along the union between the two walls to seal water out.

Hopefully my pic went through.
Thanks.

Offline fcpnorman

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Re: Cabin Roof
« Reply #1 on: November 23, 2017, 12:53:10 PM »

Offline Don_P

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Re: Cabin Roof
« Reply #2 on: November 23, 2017, 06:52:59 PM »
No joy on the pics. The site built beam sounds dubious. If there is a load bearing wall under the pitch change then a wall above that point up to support the new rafters somewhere in their span is another way to support or help support them.

Offline fcpnorman

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Re: Cabin Roof
« Reply #3 on: November 23, 2017, 08:17:41 PM »
Tried twice using Photobucket... no luck. What are your thoughts on having trusses built?

Offline fcpnorman

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Re: Cabin Roof
« Reply #4 on: November 23, 2017, 08:24:28 PM »

Offline fcpnorman

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Re: Cabin Roof
« Reply #5 on: November 23, 2017, 08:25:36 PM »

Offline Don_P

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Re: Cabin Roof
« Reply #6 on: November 24, 2017, 04:26:15 AM »
Got the imgur, I'd look at trusses swung 90.
The main problem with some type of truss marrying up onto old work like that is getting things to fit and plane in. There's usually a lot of fussing but certainly worth talking to the techs about. Is there a load bearing wall under the pitch transition?

Offline fcpnorman

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Re: Cabin Roof
« Reply #7 on: November 24, 2017, 07:16:39 AM »
Don- yes there is a load bearing wall at that point in the roof. There are a series of laced posts set on concrete footings in the walk out basement. I know it will need to have some engineering done, but I am trying to start some planning now. In my mind- I would nail up a ledger along the pitched roof after stripping back the shingles and extend the new rafters out from there to the edge. I do think I would need a beam or purlin to pick up the load- as the run from the pitched roof to the edge at the base is 18 feet. Probably closer to 20 at the point at which I would have to come off the achieve the 4:12 pitch that is required by code to put on comp shingles or metal roof.
I should probably explain the interior beams a little better. They are 2x8's that are sandwiched on the 4x8's that make the A-Frame. They are open with a piece of 1x nailed over the lower opening within the cabin- but then sandwiched to a 4x8 beam as they leave the cabin to the exterior.
I am guessing that gave them the strength to hold up the eaves, or it may have been an aesthetics thing. I still think I may need to cut the eave line back to do the roof over roof.
Thanks.

Offline Don_P

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Re: Cabin Roof
« Reply #8 on: November 24, 2017, 01:17:02 PM »
Good, if there is a load bearing wall under you at the pitch change, then on the flat roof above that build a short wall to support the new rafters. The rafter is supported down low at the outer wall then 18' later it crosses the cripple wall that supports the overhanging few feet over to the ledger nailed across the A frame roof. That ledger takes little or no load.
I'm still not following the built up beams  ???
I imagine you will most likely be redoing the eaves as part of the new roof framing.

Offline DaveOrr

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Re: Cabin Roof
« Reply #9 on: November 24, 2017, 06:16:39 PM »
Why not remove the current membrane and then affix a sloped roof on top of what it there and properly flash where it joins the existing A frame?

Of course this would not work out if there is rot in the existing.

Dave's Arctic Cabin: www.anglersparadise.ca

Offline fcpnorman

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Re: Cabin Roof
« Reply #10 on: November 24, 2017, 08:25:45 PM »
I could do an foam overlay on the existing roof and have a pitch built in. The roof membrane would be a white cool roof- similar to what you see on a lot of commercial buildings. A local roofer suggested that- I think he referred to it as Thermo polyethylene roof. They apply a foam overlay and then vinyl type roofing and heat seal the seams. The roof is guaranteed for 15 years. I think the aesthetics of a whole new roof will be better. The cool roof would be about $2-3000. I am in need of a new roof on the remainder- so I might just do the roof over and re-roof the whole thing. Going to look at metal- but may end up with comp shingle...
 

Offline fcpnorman

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Re: Cabin Roof
« Reply #11 on: November 24, 2017, 08:35:23 PM »
Don- I like the idea of the cripple walls. The 2x8's are the support for the loft- each nailed to the beams that make up the A-Frame and that creates a void space between the 2x8's. They placed a piece of 1x to create a finished look. Where they leave the exterior they are a solid beam. My guess is they placed a 4x8 in between and let it out at the exterior bearing wall. I have been sanding down the wood( it was painted) and removing the 1x bottom piece to sand on a flat surface rather than above my head.
I have furred out the interior A-Frame walls with 2x6 and insulated between them and then applied a blue pine T&G over it. This still leaves some of the original beams proud of the new paneling. I have rough sanded leaving some small traces of paint- it is giving it a re-claimed look.

I will post some pics of the interior.

Offline DaveOrr

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Re: Cabin Roof
« Reply #12 on: November 25, 2017, 05:40:46 PM »
I could do an foam overlay on the existing roof and have a pitch built in. The roof membrane would be a white cool roof- similar to what you see on a lot of commercial buildings. A local roofer suggested that- I think he referred to it as Thermo polyethylene roof. They apply a foam overlay and then vinyl type roofing and heat seal the seams. The roof is guaranteed for 15 years. I think the aesthetics of a whole new roof will be better. The cool roof would be about $2-3000. I am in need of a new roof on the remainder- so I might just do the roof over and re-roof the whole thing. Going to look at metal- but may end up with comp shingle...
 

I was more thinking of building it up to be 3:12-4:12 pitch and then you could use the same roofing materials as the A frame.
This would give you excellent drainage and if you did metal would last forever.
Sort of similar to how I did the porch roof on my cabin. 4:12 over the porch into 6:12 over the cabin.




Dave's Arctic Cabin: www.anglersparadise.ca

Offline fcpnorman

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Re: Cabin Roof
« Reply #13 on: November 26, 2017, 08:39:28 PM »
That is the plan- I think. I would build two pony walls , one at the A-Frame and one at the opposite wall. The new rafters would slope in a shed style roof. This would allow me to get the pitch I would need to do metal or comp.
I am going to do some research on the foundation and support to determine if would support a second story. The other option is to do a patch on the leaky section until I am able to possibly build a second story. That would be a few years from now.
Right now having an issue getting a roofer to call me back- might be doing the patch myself...