Covered deck tied to house - how to

[walkabout]

Guys, I am planning/designing/building a model of the cabin I would like to build later this year and have a question regarding how to link a covered deck to the main house structure. I would like to build a "dutch gable" like roof (thanks ScottA for the idea http://countryplans.com/smf/index.php?topic=3419.msg69450#msg69450), but unlike ScottA's house the gable will be covering a deck and not supported by the same foundation as the main house.
Here is a drawing of what I would like to do:


My concerns/questions are:
1. Since the deck will be supported by cement footers, while the house will be on a block crawl space, do I need to worry about the cement footers settling/moving at a different rate than the house?
2. Should the vertical beams sitting on the cement posts run all the way from the cement post to the roof line? Or from the cement post to the deck, build the deck and then have another beam from the deck to the roof line?

Here is a photo of the latest stage of my model:


Walkabout
https://s677.photobucket.com/albums/vv137/home_walkabout_usa/Cabin%20rebuild/

[devildog]

your stick house looks great! I tried that and after afew sticks found I didnt have the patience.

[John Raabe]

If you build full depth (same as house) footers under the porch post piers you should have equal settlement to the house (hopefully zero).

I like to have the porch foundation piers support a 6x6 post and then carry that all the way to the roof beam and have a bolt on ledger beam carry the porch floor joists. I would also have a couple of more posts to carry the roof and porch floor beams. Otherwise, you will have quite large & expensive beams spanning the full width of your model.

[walkabout]

Thanks for the advice John.

Is this what you had in mind? Obviously the 6x6 post won't go all the way to the depth of the main foundation footer as there will a footer covering part of the distance under the deck:



Building a model has not been as difficult as I thought thanks to lots of scrap wood and HOT GLUE. Once you get one wall up the others go up really easily. I have already made a few mistakes and would change a few windows etc around next time so it has been a great experience.
I hope building a real cabin would go this well.

[rwanders]

   Great model! I have worked on some large industrial projects that brought detailed scale models to the jobsite---incredibly useful to all the crafts and engineers----really helps identify interferences and resolve them.

I assume you just like the look of the dutch gable----I would probably extend the main roof out over the porch instead.

[walkabout]

I like the look of the dutch gable as it adds some nice detail to a fairly standard design, but have also thought about just extending the roof all the way over the deck like you suggest as it should be much easier to build.  I might change my mind though when I actually try to build the dormer.

[Bobmarlon]

That model is awesome,  I think I might attempt to  build a model like this.  What size wood did you use did you cut it yourself.  Any model tips would be appreciated.

[walkabout]

Bob Marlin,
Here is some advice:
1. try to build as true to your plan as possible. You will figure out what you would do differently when you actually build the house, but the experimentation did not cost you anything.
2. repitition is good as by the time you get the roof up, you have all the framing techniques mastered although at a small scale.
3. try to cut your lumber as true to scale as you can, although cutting thin pieces of wood on a table saw is difficult.
4. where you can't cut the 2x4 material to thr correct thickness, use a thicknesser/planer to get it more accurate.
5. mistakes are realy easy to fix in a model, if you catch them right away.
6. take your time, and read this forum, read as many books as you can.
7. use a 1/12 scale ruler
I did have to find a source for a 1/12 scale ruler, but all I could find was an image that I printed. Because 1 inch in the model = 1 foot in real life, 1 inch on the ruler needed to be divided into 12ths instead of 16ths, so that each graduation is an inch in real life.
Here is the PDF: http://zooplies.com/PDF_Files/12th_scale_ruler.pdf
8. I use white cardboard for the walls and roof, so that I can paint them the color I intend to actually use, that way I can visualize what it will look like.

I cut all the wood myself using scrap (2x4s and 3/4inch). The only cost I have so far into this model besides time is the hot glue gun ($13) and some white cardboard ($9) and a think kerf ripping blade ($6).

My friends and familly laugh at me at spending so much time on a model, but I treat it as a fun learning experience. What else can I do when it is -30F here in Minnesota!!

rwanders,
I attempted to create the dutch gable last night and all the compound angles gave me a headache. I did further reading and discovered that what I am attempting is not even advisable for experinced carpenters. I was going to try and have the gable roof have a different pitch to the main roof, which then makes it even more difficult.
I might take your advice and just extend the main roof all the way over the deck.

[rwanders]

My cabin with an extended 12/12 roof over double decked porches---thought you may like to see an example of how that looks.

[Bobmarlon]

Thank you

[walkabout]

rwanders,
I took your advice and extended the roof just like your cabin, but had some questions as to how you support the 10' overhang:
1. is the railing of the upper deck supporting the roof?
2. Do you have a single ridge board covering the 24' of house plus the 11' extension? If not how do you tie the extended roof's ridge board to the main ridge board.
3. Would I need the horizontal rafter tie? (the one that is tied to the center columns)

Here is what I accomplished tonight:

[rwanders]

My roof is supported by a single glulam ridge beam 6"x16"x36'  (extends over the 24' cabin, the 10' decks plus a 1' overhang at each end) This allowed me to go without rafter ties or collar ties inside the cabin.

The beam under the upper deck ties the roof together at that point and supports the upper deck. A 4x6 beam extends from the cabin corners and is tied to the corner posts and the beam spanning across the width of the deck whose joists are 2x12 16 OC with 2x6 T&G pine deckboards. My floor joists are 11" wood I-beams 16OC which gave me a rock solid and level floor. My loft floor joists are 2x12 16 OC but only span 10' and land in hangers on a 6x12 glulam.  I could have built lighter but, for a relatively small extra cost I have a very stout cabin. I believe you will need the horizontal beam to tie the roof together but, John Raabe would be able to confirm or deny that better than I can.

If you are planning to have a loft or would like a high ceiling---using a ridge beam instead of a ridge board provides the structural strength to delete a lot of lumber and labor though the beam is not real cheap. If you go for a cathedral ceiling, as I did, I recommend exploring the use of closed cell polyurethane foam blown into the rafters----you can achieve very high R values and will not have to ventilate the roof or put up a separate vapor barrier in the ceiling. Open cell or icylene foam does not provide the same impermeability rating as closed cell though or achieve equivalent R ratings---closed cell can reach 6 R per inch.

[walkabout]

Wow, If I went with a single glulam ridge I would need one that is at least 40' long as I want to have a 20x30 foundation with an 8' deck and 1' overhangs on each end. I was going to try to get approval for a 20x40 foundation which would push the ridge board up to 50' which I don't think is feasable. I do want to have cathederal ceilings in the main living area and would like to avoid rafter/collar ties.

I will have to do some more reading on the forum to see what other people have done as I distinctly remember specific discussions on ridge boards/rafter ties etc.

I will not be looking into ceiling insulation till the cabin is dried in as I don't believe it changes the framing options, but have seem the blown in closed cell foam and it does appear to be the way to go but does require more $$.

[John Raabe]

Remember, there are two ways to support a roof.

• One is with structural beams or support at the walls and ridge. The rafters then span between them.
• Two is to triangulate the roof forces with trusses, collar ties or some other method of locking the walls and moving the outward forces into the sidewalls.

You might consider the simple built-up rafter ties I show in the cathedral ceiling details for the 20' wide house plans. This works just as well with an open porch roof. See the interior shots of this house - the living room has rafter ties at 4' o/c. You do not need a ridge beam for this, only the ridge board you already have in your model.

http://countryplans.com/smf/index.php?topic=1503.msg13982

Note: You will need beam supports at the side wall but only the depth of the porch.

[rwanders]

Walkabout: One other suggestion for your consideration-----I don't know how much snow fall you have to contend with---I get quite a bit so I extended the eaves 5 feet past the side walls to avoid snow piling up against the cabin. It has worked like a charm. When the snow slides off my roof, it piles up high but leaves a clear area alongside of about 4 feet--just right for my walkway and access to my fuel oil & propane tanks. I lived in Valdez  Alaska for nine years and we averaged 330 inches per year---record was in 1989 when we got 47 feet!  Not nearly as bad in Willow but still get lots of the white stuff. It made me very aware of planning for snow when I was designing the cabin.

[walkabout]

We get a fair amount of snow here in MN, but not enough to warrent 5' eaves. The last few years people out east have been getting much more snow that in MN. We still get the occasional -35F day though!!

If I did this I would need to increase my wall height so that the eaves did not go below the tops of the windows and block my view. My house in the city does not even have an overhang on the gable end and we seem to do ok, so I guess we actually don't get that much snow.

[walkabout]

John,
I added the rafter ties per the plans and was able to eliminate the 2 center columns above the deck. This looks much cleaner:


I also added the interior rafter ties and the ceiling joists:


Thanks all for your help.

Walkabout
https://s677.photobucket.com/albums/vv137/home_walkabout_usa/Cabin%20rebuild/?albumview=grid

[rwanders]

   Like your new porch detail--very clean indeed! If the care you put into your model is any indication, your cabin will be beautiful. Look forward to pictures as you build.

[John Raabe]

Walkabout:

While I think you have taken account of the downward forces, this open front porch looks vulnerable to the twisting forces of wind or earthquake. I'm not enough of an engineer to be able to quantify those forces but perhaps a king post truss at the porch face tied to another post or two might stabilize that front face.

It almost feels like it needs it "visually" - if only to look more stable.

[walkabout]

John,
I am not sure what changes you had in mind, but I drew some lines on the photo as I think I understand what you are talking about:


I put 2 options, one (red) being above the rafter ties and another (blue) below the rafter ties.
I have seen cabins with the red option near ours which appeared to be decorative as they looked like a 1/2 wagon wheel.

Also here is a photo with ta vertical beam as well:
http://idahocontractor.com/images_projects/breedlove_frame_porch01.jpg

Was this what you had in mind?

[John Raabe]

Yes, this could work.



Here is another way to go...



I realize this goes back to the ridge beam idea but it is a short load from the wall line.

The extra posts also support the railings it seems you will need.

[walkabout]

Thanks again for your advice John.
I did as you recomended, but was not sure if I could illiminate both rafter ties if I added the horizontal and vertial beams here.
Either way I believe I have enough now to submit my plans: