Al and Robins 20x30 1 1/2 near Lake Eufaula, OK

[ajbremer]

Sunday Afternoon - March 4th, 2012 Mid-Oklahoma

Thanks again Don_P and thanks for the comment Bob S.,

I plan to support the beam in the exact middle width (10 feet) of my build at both gable ends
and not only there but also with a post/column/tree at the 15 feet half way mark.

So the beam will be supported at the ends and in the middle at 15'. So therefore the beam will
have two 15 foot spans.

A question about the gable end support posts: Can I simply sister 2x6 studs to one another, maybe
even have like 3 or 4 2x6's together in the wall cavity holding up the beam? Or, would just doubled
2x6's work?

I already have a 32' long 2x8, I could purchase a second one and then cut them to the 30' length.
I could lift them into position one at a time and then glue and nail them together up there. I
could also sandwich OSB in the middle of them and glue them all.

Would that be good enough to support the 10lbs per square foot of roof? I haven't found a chart showing
the load for site made beams. Maybe it's because site made beams are not accepted as code?

Here's me lifting the 32' long 2x8 (that I WAS going to use for a ridge board). This pic is
also a couple of pages back:









Here is the house back to the 12:12 full length pitch. You can see that I have my
loft windows divided so that the ridge beam support post can pass through. Here's
the East gable:



Here's the west gable end;



Now here's the house without its roof. You can see the catwalk is offset enough to one
side so that a post can go in the exact middle of the house to split the beam length
difference and the catwalk can also be braced to the side of it to help with the catwalk
support (post is not in picture). By the way, there is plenty of head room walking down
the catwalk in the middle, about 6'4". Please let me know if I'm on the right track:

[MountainDon]

Would that be good enough to support the 10lbs per square foot of roof?

I'll defer to whatever Don_P has to say but with a 12/12 pitch roof you have more materials, rafters, sheathing, roofing, than with a lower pitched roof, so I believe the dead load number might be more like 15 psf.   Or use 10 psf but use the real area of the sloped roof which is about 1.414 times the area of the floor (with 12/12)   not sure on that.....

Plus there's the LL (live load; rain, snow, rain, a future hired roofer at 250 lbs....) That's got to be at least 10 psf.  The truss mfg. you got quotes from all used 20 psf IIRC, which is a good idea, good safety factor. Who knows what tricks and surprises our weather will throw at us these years?

I'm sure Don_P will have some suggestions for the components needed to safely use a ridge beam.

[ajbremer]

Thanks MountainDon,

That's something that I forgot to think about - more surface area of the 12:12 roof. Have a nice night
Don.

[MountainDon]

   curious, I tried some numbers...
I don't recall if the species/grade was given for that long 2x8, so I used #2 SYP and 35 psf roof loading, using actual 20x30 measurements, a 15 foot long ridge beam section, I came up with needing a three layer 2x12 to Pass on Fiberstress in Bending, Deflection and Horizontal shear. Two layer failed on Deflection and Fiberstress in bending.

Values were pulled from the AWC rafter/joist info for 2x materials.  Wrong/Right/Okay thing to do? 

So am I close?  Or way off?  If I'm way off in the direction of spec'ing too big a beam, I am sorry to have scared you Al.

[MountainDon]

And then I got to thinking about the center column for the ridge beam.... How is it going to be supported so it acts like a nice strong unbending, non deflecting, column and not like a piece of spaghetti?   

[Don_P]

MD types with more than 2 fingers thi is what I was working on;

Judging by you having it under one arm I assumed #2 SPF. I tried 2x8's and was still failing by about 250% at 4 ply. Ripped down it would make a nice 1 piece subfascia on one side.

4 ply 2x12's in #2 SYP or 3 ply in #1 SYP would work, but a double 30' long 11-1/4" LVL works by my math and would be my choice. Do not break it over the post, full 30' or the deflection gets bad. That configuration has reactions (the post loads) of about 2,000 lbs at each end and about 3 tons in the center. The supplier can check it. At 5.2 lbs/ft x 30'= 156 lbs... I can stick one end up in pocket and carry the other end of that up a ladder.

I like the tree column. I assume it's forming the inside corner of the stair/loft handrail and is directly over a pier below. Beef up the bearing under these point loads, block it solid under there. Think about that pier and footing... good enough?

The gable ends need some thought. Typically I'll bear on a pair of built up 2x6's with 1/2" ply sandwiched to give 3-1/2" thickness, then run a 2x6 full height up each side to make a 4 ply built up "yoked" column. I'm typically running this from the floor up. There is a problem with the wall right there.

It looks like the west end of the catwalk can bear on a wall, the east end needs to bear on an lvl beam. Any reason not to just extend the catwalk/loft over the kitchen to the sidewall... just a thought?

[Don_P]

MD, I was heading here for the euler buckling/ spagetti column problem;
http://www.timbertoolbox.com/Calcs/Simple_column.htm
The center column should be connected to the catwalk floor to laterally brace it at that level, so its' effective height will be from 2nd floor to ridge.

You can back out the example inputs in the calc and plug in your own inputs. I selected #2 SYP 6x6 for the center post and checked.

To confirm your roof dead load line of thought I plugged 10 psf dead load and 12/12 pitch into the I level program and it spat out an adjusted dead load of 14.1 lbs... 1.414. So yes live load is taken as the horizontal projection, dead load is the surface area, the actual weight of the materials... or use 15 psf on steep roofs.

[CjAl]

hurry up so you can sell me that camper. 

[ajbremer]

Monday Morning - March 5th, 2012

I just ordered 2 12" x 30 foot long each (11 7/8) LVL's. He said there about 1 7/8 thick. They were $133.00 a piece. The lumber guy
said that it'll be well overboard to hold the weight of the roof.

Oh, ya - thanks for the comment CjAl, I just might do that...not sure.

[rick91351]

Monday Morning - March 5th, 2012

The lumber guy said that it'll be well overboard to hold the weight of the roof.

I agree under normal conditions.  But never build for the normal. 

[ajbremer]

I agree rick91351,

Too many people build to 'normal' conditions and normal seems to only get worse with time. I hear of many people
who build 'the way it's always been done around here'. Well, weather changes for the worst, science and technology get better, we
also hopefully get smarter with computers and such and therefore the building process gets better and the end result is a stronger
home...if we listen to people like the smart guys here on this forum.

A little ridge board with 2x6 rafters and no lower ties seems massively common around here but yet it keeps being done. Those
homes seem like their still standing good with no complaints but I feel better when I don't 'build to the normal' but go ... 'to infinity
and beyond!' like many here suggest. Thank you all.

[suburbancowboy]

Your design for the upstairs is so much like mine.    Only difference is I will take the wall clear against the stairs.  I will need a bigger bed room upstairs, I plan on lots of guest and as the kids get families they will need the room.  The room on the upper level will be the kids play/family room and over flow bed room.

[Don_P]

The smart guys we're supposed to be listening to are engineers   
A note of caution on "infinity" here, these are some very light design loads. Don't copy, size the parts according to the conditions where the house will be built.

I suggest 2x12 rafters on 24" centers. The plumb cut on the top of that rafter will be almost 16", the ridge is about 12" tall. I would set the ridge so that its' bottom edge is flush with the bottom edge of the rafter. I would attach 2 layers of 2x4 flat on top of the ridge to provide supporting fill for the rafter upper edges. This will leave about an inch of airspace over the top of the ridge for airflow. I typically nail each rafter up with at least 5 toenails and then come back with 9" framing angles nailed to the ridge and the rafter, 1 per rafter.

I would build the ridge support post as 4 plies of 2x6 with a 1/2" osb fill layer in the center. The outer 2 plies extend up 14-3/4" above the center plies to form a yoke that the ridge will drop into and be well nailed to.

The gable end walls should really be framed under the floor. This would entail cutting them down. I'm pretty comfortable if there were either a web filled I joist or a solid sawn floor joist securely fastened to each stud of the tall wall. The floor plywood then nails to this well attached ledger joist and the floor diapragm is attached to the wall. A few twisted hurricane ties from studs to floor wouldn't hurt. At this point you can slice out a section of the top plate for the ridge support post to drop though down to the window header, which is stout enough. The left side of that window framing is floating, pull those cripples tight and nail it all together well. We fret over the members but it is typically the connections that fail, nails are cheap, go back over this area and make sure everything is well nailed off. When the post is in place lock it in and support it with blocking in the wall, attach the sheathing to it well. Where the post passes thru the cutout in the plate use a 5" framing angle to connect the plate to the post on the underside. I would find nice strong single pieces to make a third top plate running from post to roof in each direction. Then I would install a framing angle from that top plate to the post on each side. I'm pretty sure that locks the hinge in the wall and saves alot of work. Everywhere a balloon stud passes thru the floor needs to be blocked to block that fire path from below.

The west post should begin on the first floor bottom plate and run up to the ridge, attaching to everything on the way just like before. The joints in the plies should be offset as much as possible to weave the post together into a strong unit, and then block it into the wall.

this ridge can support dormer rafters with no thrust, just noting that signpost before we pass it the last time

[ajbremer]

Tuesday Morning - March 6th, 2012 Mid-Oklahoma

Thanks suburbancowboy and Don_P,

Taking the edge of my catwalk all the way to the wall is a good idea, I just may do that. Planning for the grand kids is an excellent idea. Doing that would delete the catwalk and leave one big 'hole' to look down below.

Me and one guy were talking about how I have a couple of 'holes' looking down in my loft using a catwalk. He said, "What ever ya do, don't have holes in the second floor, it'll get way to hot up there when you heat the downstairs and you'll have to open windows every time." I guess that's something to think about.

Don_P, thank you for all the information once again. You have made things clearer for me. Was it right for me to order my ridge BEAMS 30 foot long? Now I'm wondering if I should have ordered them to be around 32 or 34 feet for barge purposes or should I stick with the 30 feet? I'll call them up early this morning and change my order if need be.

One thing Don_P mentioned at the end of his post was: "This ridge can support dormer rafters with no thrust, just noting that signpost before we pass it the last time." I forgot all about that Don. I guess I could go back to the idea of knocking down my 10 foot walls to the 8' height, platform the 8' walls on top of the loft joists and sub-floor, and go back to the pitch change idea - seeing that they'll be no thrust because of the ridge beam.

Is there anyway that I could keep the 10' walls and build a 5' wall on top of them for that loft section? Support could come from the gable end and studs between the pitch change rafters and their sheathing?

I think I've figured this correctly, since I'm going 24" o/c for the rafters (and using the pitch change idea), I'll need 16 2x12's 18' long and 16 of them 16' long for my rafter order. I don't think 16 footers will be enough at the 12:12 pitch but it should be enough for the 6:12 pitch idea over the loft. Would I have to add another 4 rafters for each gable end barge?

As far as figuring out how high to place my ridge beam above the top plate of the wall, wouldn't it be 10 feet because that would be 45 degrees? Or, do I take it a little higher to account for rafter plumb height above the birds mouth? Oh ya, how long should my birds mouth seat cut be for the 12:12's and for the 6:12's? I've read where it shouldn't be more than 1/3 of the rafter depth?

[CjAl]

since the 45%cut on a 2x12 is 16" you would want the bottom of your ridge beam 8' 8" (16" less then 10') plus the height of your first floor walls.

[Don_P]

The LVL's are the right length, I let the lookouts carry the fly. You can extend the double 2x4 out as a spacer to nail to.

I'm not comfortable bearing the dormer roof on a wall like that. If you want to do it I'd bite the bullet, it'll take a day.


Assuming the framing is 20' wide and then you added 1/2" sheathing making the full building width 20'1".
I'd make the birdsmouth with a 6" level seatcut to bring the lower edge of the rafter to the top interior corner of the top plate.

From the above 241" building width, subtract the 3.5" ridge tickness and divide by 2 to get the individual rafter horizontal span. (241 - 3.5)/2= 118.75"
The plumb to plumb line length of the rafter is 167.93". you won't get more than about a 12" overhang out of 16' material, I agree on the 18' length.

The bottom of the ridge is 116-3/4" above the plate if you make the cuts as above.

[ajbremer]

Wednesday Night - March 7th, 2012 Mid-Oklahoma

Thanks Don_P

I was wondering, you figured out all those dimensions of the ridge board, seatcut, rafter length, etc. Did you use long hand calculations for that or do you use some kind of software or online calculator?

Well everyone, I'm excited about tomorrow because the lumber company will be delivering those two LVL beams that are 30 foot long each. It'll be the first time I've ever seen LVL's. I have decided to also keep my 10 foot walls and go with the 12:12 pitch all the way.

Today, after work, I finished sheathing the upper portion of the west gable end. There's a chance of rain coming up in the next few days and I hate the thought of rain on my floor now. The Advantech flooring is holding up very well throughout this whole 'mild' winter but I still don't like the thought of all that water all over my wood.

I have a little more sheathing to do and then I will start on the rest of the interior walls which are very few.

Where I really want to be is to the point of putting in those i-joist. I'll be making web stiffeners at the point of where they intersect and connect to the long walls. I will hold them up by sistering joists under each one. Then I'll be putting 5/8 sub-floor on top of them...maybe I should use 3/4?

By the way, I was a little bit delayed in building for a couple days (ok, maybe only one day). yesterday, my son had to be taken off the road (literally), into an ambulance, and to the emergency room. Another vehicle pulled out in front of him - he was on his motorcycle. Many times he didn't wear his helmet but me and his mother would just about yell at him and tell him to wear it. We never wanted him to have a motorcycle - I just don't see the logic of riding down a road going 50, 60, 70, ot 80 mph with nothing around you - and many people don't wear a helmet, it's crazy!

Anyway, Nathan - my son, was wearing a really good helmet, the day before the accident he went out and got him one of those kevlar bullet proof elbow/back padded leather riding jackets. He had the tall Harley boots and everything. His helmet broke in the accident, it had about a 3" slice in the very back bottom. He's ok, he wasn't even admitted into the hospital. He ended up with a cast on a broken Rt. foot, staples in his head, a concussion, and road rash. We pray for the protection of our kids all the time - he's 24 years old.

He had to have someone take care of him for a few weeks while he hobbles along on his cast and waits for his surgery. Well, we live in this little 30 foot RV while we build our countryplan house so it would have been a handful to take care of him. His twin sister and my son-in-law decided that they would take care of him and he can stay there for awhile. Wow, that's something that I never thought of when I decided to live in an RV and build our house - having to take care of a loved one. (A wheel chair can't fit in the rv).

Anyway, thank you once again for all of your comments and suggestions. I read them over and over again so that I can try my best to understand them all.

[Redoverfarm]

Al generally 3/4"  T&G is used for subfloor. It doesn't have to be Advantex like the exposed flooring you have now. Chances are you will have a roof on before it is done so no need for water protection.   5/8" usually for roof sheeting.

Sorry to hear about your Son. Hope he mends fast.   As the saying goes " been there and done that".  Then I grew up.

[ajbremer]

Thursday Morning - March 8th, 2012 Mid-Oklahoma

Thanks Redoverfarm

Those dimensions help me out a lot.

As far as your motorcycle "been there done that", me too but on a bicycle. I used to ride bicycle all the time, even cycled across America twice - once in 1984 - did 4,200 miles on my 10 speed in 62 days. Then again in 1986 on a tandem with my wife - did 4,600+ miles that time in 80 days. Been hit by a car twice throughout my cycling days - a few broken bones, nothing major.

It's raining here now. Soon I hope to be under my new roof - it'll be cool! 

[Don_P]

I got tired of doing the calcs longhand. I'm not sure if it'll help or not, I wrote some calcs for figuring it.
This one figures the ridge support height;
http://www.timbertoolbox.com/Calcs/ridgehgtclc.htm

This one rafter length... not sure why I didn't put them together ;
Since you don't have a hip or valley enter "0" in that box.
http://www.timbertoolbox.com/Calcs/raftercalc.htm

I used 118.75" for span... add for the sheathing 20'1", deduct for the ridge thickness -3.5, Divide total by 2= 118.75" horizontal span.

I've never used 5/8" for a floor, but I've also lived in a house that had no subfloor just oak flooring. I like 3/4 advamtech. We subbed regular 3/4 osb in the loft on a job last year. One rain and the difference in quality was very obvious.

Sorry to hear about your son. Staying with sis, I'd have a real fast recovery  .

[ajbremer]

Thanks Don_P

Those online calcs you mentioned are going to be helpful, I'm going to mess with them as soon as I get a little time. You mentioned that you wrote the calcs? Is that your website and did you program those calcs in Java or something? Awesome job if so.

I programmed a Trigonometry Android App in Java a little over a year ago, I think it's got over 500 users by now. It has helped me out in the shop many times. If I had the time, I could sit down and program 10 or 20 Android apps and then maybe I could quit work and just work out of my countryplan home?...ah, I don't think so - I don't want to put all my life into programming all day long all the time - been there done that.

Thanks Don.

[ajbremer]

Thursday Night - March 8th, 2012 Mid-Oklahoma

Well, it rained most of the day but it's not raining now. I got out in my countryplan build and tried my best to sweep the water off of the Advantech. The Advantech is performing great for being exposed this whole winter but I can see it discoloring a little bit and also there are a very few tiny spots where it's flaked up...barely. I'm pretty sure OSB or Plywood would have been totally wasted by now.

Another thing I can see by the rain on my floor, it's not perfectly level. There is one particular low spot where the water stays more than anyplace else. Maybe when I put my wood floor down on top of the sub-floor, it'll get a little better.

I sure wish I could do the loft joists and floor AFTER I get the roof done. My first thought is that the walls need the joists connecting them together for strength but now that I'm doing the ridge BEAM, could I do my roof first? I do have one interior wall connecting the long walls together. I could set up scaffolding...ah, maybe I'm just getting ahead of myself and being impatient. I just hate to see the place getting wet on the inside, that's all.

[metolent]

I wouldn't worry too much about the wetness - it will all dry out.  I recall shoveling a foot of snow out of my place at one point, only to have it turn to rain the next day, followed by another foot of snow a couple of days later...and despite the fact we live in the PNW, where it's known to rain occasionally, I didn't use Advantech.  Only a month later I thought things were pretty dry until I brought up a propane heater to take the edge off.  As it began to warm up a few degrees, it started to rain inside.  At first I thought the roof was leaking, but after further inspection I realized there was quite a bit of moisture on the underside of the sheathing that had previously frozen. I was thawing it out with the heater, creating a nice indoor rain shower.    

Btw, congrats on getting through the decision process on your roof!  And I hope your son gets well soon.  Looking forward to seeing your progress.... 

[Don_P]

It is tough to watch it get wet, generally it doesn't do as much damage as our fears. Do keep it swept off and keep the sawdust cleaned up, that stuff is like a sponge. I've lived in the motorhome in front of dozens of houses... I know you are keeping it swept and as dry as possible.

Do the floor first, don't rush, be efficient but don't cut corners. The floor braces and ties and makes a much safer work platform.

If the girders were level and in plane... and if the posts are not sliding into the piers or the piers are not sinking, then the pooling is likely the crown of the joists making a low spot between them.

The calcs are in javascript, that is my site; timbertoolbox.com
I'm not very computer savvy, if you can tweak them please feel free.

[ajbremer]

Saturday Night - March 10th, 2012 Mid-Oklahoma

I sheathed most of the day today, only a little more to go and the outside will be done.



I also got a load of lumber delivered, in it was those two 30 foot long LVL's. They are I-Level
Truss Joists: 1.9E - 11 7/8" x 1 7/8". I went to ilevel.com and looked them up and I think
I saw that they are 6.0 pounds per linear foot - 180 lbs each. I lifted one end of each of them
to move them but there's no way I can lift the whole thing.

I decided to buy 1 - 2x12x18 foot long board (about $21.00) just to see how heavy it was, how
it looked, how manageable it is - wow, what a board! I weighed it and it weighs 95 lbs. Hey,
that means that there will be 32 of these 2x12's so that is: 3,040 lbs BUT, isn't it true that with a
ridge beam - 1/2 the weight of the roof is on the beam and the other half on the wall? Anyway,
Here's me lifting that 2x12:



Here's the 2 LVL's at the left of the picture and the 2x12x18 to the right:



Came home Friday to see the lumber company plopped my lumber right in my driveway:



I also started to work on the east gable end, began to tear away the top. I plan to do as Don_P suggested
and put 4 plies of 2x6's with a 1/2" osb fill layer in the center. I'll rest on the 2x12 headers above the window and then pop through the top plate and go all the way up to where the ridge beam will sit into it. The 2 outer 2x6's will go beyond the 2 middle ones in order to 'trap' the ridge beam inside it.



Lastly, Don_P mentioned how I could attach my rafters to the ridge beam. I've also read of other methods described in the pic below. I like the way the upper-left configuration looks - how bout that one?