24 x 32 in Alabama

[scottbama]

Not sure if I am in the right forum but here it goes. I am attempting to build a 24 x32 and would like to know how to ensure that I have my weight distributed to the outside walls to prevent from having load bearing walls on the interior. I am also going to attempt something here to see if this will work. I am attaching my Facebook link to the album of pictures I have take on my project. http://www.facebook.com/#!/media/set/?set=a.1737773636630.2088227.1007283699

I realize there are some warped boards in there but hoping that I will be able to straighten most of them out when I begin to place the supports in between the floor joists.

Scott Gleaton

[John Raabe]

  Scott

I'm first off wanting to understand where you are at with your project.

Is this about right?



This is single story no loft, right? How is the roof framed? Is there a load bearing beam? If it is trussed then you may not have interior load bearing walls.

[scottbama]

Don't know how you did that on the picture but that is wicked cool! The roof is simple 2x10 with collar bands in the roof line. I do not see any wall that calls for a beam except between the main floor and dining. John you are correct on the status of the project. THANKS!

[rick91351]

Don't know how you did that on the picture but that is wicked cool!

He has special secret powers - that is why he is the owner of the web site!    (And we are not!)

[John Raabe]

Any secret powers I might have are due to the SnagIt image capture program. I can hit Print Screen while on you Facebook page and copy the image - then SnagIt lets me add lines, callout boxes, text and other items to the image. I then save it to my desktop and upload it to my free Photobucket account that will give the image a URL. That gets copied into the forum post. With this you can grab images from websites that will not allow you to post a link directly. Here's more info: http://countryplans.com/smf/index.php?topic=3512.0

If your roof is stick framed, it probably has collar ties (up near the peak) and rafter ties (near the bottom of the rafters or at the tops of the walls). A continuous ceiling joist will serve as a rafter tie if rafters and joists are nailed well at both ends of the ceiling joist. The collar tie at the top can often be replaced by a metal strap that is nailed into rafters on either side of the ridge board.

[scottbama]

Very Cool! That really helps me! Cannot wait to get that far along, money available and Lord willing!

[scottbama]

I have a bit of a dilemma. I suppose it is more afraid I will mess up something more than not knowing what to do. Built the wall with my exterior door opening and put in a 2x12 header and used 92-5/8 studs. The door is ever so slightly taller than the opening. My question is, can you remove the bottom seal plate and adjust the door frame accordingly without messing up anything? I am sure I will have to do a little carpentry work on the bottom of the door too but I think I can handle that part if it comes to that.

[John Raabe]

Consider what the finish floor level will be on either side of the door and where the level of the threshold will be. You may be able to make it up in the sill plate or nip the frame and bottom of the door. You may also be able to double the header and shave a bit off the bottom of that.

There are far better carpenters here than I so I will now shut up.

[scottbama]

Found the problem with my door framing, 2x10 needed instead of 2x12 for header. The plans stated 2x10 or 2x12. I went with the larger because I thought it would be better structurally, not so. A friend of mine pointed out to me to use 2x10.

Anyway, I now have all my exterior walls framed, next on the agenda is to get in my roof joists and interior walls. I am also thinking ahead on the roofing. Will be using 1x10 ridge board and placing 2x8 on a 6/12 pitch. I need pointers on measuring and cutting the birds mouth and how far from the ridge to place my rafter ties. I am aware of the 24" o.c. for placement, just want to put the rafter ties at the right height to make sure I have am structurally sound. These will be spanning the 24 foot by 24 foot section of the home. I will later place 2x6 on the front portion of the home at a 3/12 pitch, tying those to the 6/12 rafters.

Thanks!!
Scott Gleaton

[Don_P]

You can use a 1x for a ridgeboard but it is more conventional (and gives better nailing) to use a 2x. Make sure the bottom of the plumb cut on the rafter is not below the ridge. The bottom of the plumb cut should be supported by the ridgeboard to avoid splitting of the rafter.

A collar tie needs to attach rafter to rafter across the ridge in the upper third of rafter height. This can be a 2x under the ridge attaching opposing rafters or a metal strap over the top connecting opposing rafters. Imagine the building trying to inflate, this prevents the roof from blowing apart at the ridge.

You also need rafter ties in the lower third of roof height connecting opposing rafter feet across the building. These prevent the lower legs of the rafter from trying to spread out. Typically these are either ceiling joists or upper level floor joists. Connect these to the rafters very well, the lower the pitch the greater the spreading force.

The birdsmouth level cut should not extend inboard of the wall line... the cut should be fully supported on the wall. Additionally if there is an overhang there needs to be at least 3-1/2" of wood remaining along the upper edge of the rafter for an overhang of 2' or less. The level, or seat cut, on the bird needs to be at least 1-1/2" measured horizontally to meet minimum bearing requirements.

If you are trying to span the entire 24' clear with a ceiling joist, trusses are the way to go.

[scottbama]

Thanks for the reply Don_P. The lower portion of the rafters will be easy enough to support as the ceiling joists run the same direction. I am sorry but your term, "plumb cut," confused me. In addition, I am still unclear as to how to measure for the birds mouth. What is confusing me is creating the proper angles for the cut since I am already working on an angle to begin with. I am terrible when it comes to geometry and angles!

Thanks

[duncanshannon]

re: birdsmouth - quick google search gave me these:

http://www.diychatroom.com/f19/cutting-birds-mouth-cut-rafter-38732/#post233448

http://www.carpentry-pro-framer.com/cutting-rafters.html

http://www.builderbill-diy-help.com/roof-framing.html

do they help?

[Don_P]

I haven't checked Duncan's links but here's some answers and one way. There are many and they can be used to backcheck each other. I wish they had taught me math in shop rather than the way they did, my hands are brighter than my head 

The plumb cut I was talking about is the angled cut at the top, peak, of the rafter. When the rafter is installed you'll have 2 types of cuts, vertical plumb cuts and horizontal level cuts. They are compliments of each other, if you know the angle of one deduct it from 90 degrees and you'll have the other. For instance a 6/12 is 26.5 degrees (from horizontal, but this is also the plumb cut angle on your speed square) 90*-26.5*= 63.5*...this will be the level seat cut angle on the birdsmouth. It will also be the angle on the gable siding. I usually write critical angles somewhere on the framing so I don't have a brain fart later when I'm tired.

Master class;
boiling the trig down, all right triangles have a fixed relationship between the lengths of the sides. For a 6/12 pitch the length of the rafter is 1.1180 times the length of the bottom chord.
Example: if the building is 24'1" wide measured outside to outside on the sheathing, first deduct the thickness of the ridgeboard (I'm going to assume 1.5") so 289"-1.5"=287.5" Now divide that in half to get the horizontal run of one side of the roof 287.5/2=143.75". Then multiply the run times the line length ratio from above 143.75 X 1.1180= 160.7125" or about 160-11/16" plumb to plumb.

Check crown on the rafter, put the crown up. Make the top plumb cut at 26.5*, hook your tape on the long point and measure along that edge 160-11/16" and mark on that top edge. Slide your speed square to that point swinging it in the same direction as you did for the top plumb cut and mark another plumb cut. This is the plumb cut for the birdsmouth. Square to that line is the level seat cut. Mark it at the height you want rereading my cautions from the post above. Remove that little triangle, the birdsmouth. Don't overcut the notch, rather have a handsaw handy and make a neat clean notch. Write "PAT" on that rafter and use it to mark and cut another. Carry them up and test fit, don't forget a ridge or dummy of 2x material. Check the angles to make sure everyone is happy, correct if needed on PAT and then use it to mark all the rafters. Do not use the next rafter to mark the following one and that one to mark the next or you'll be off a mile by the end, use one pattern.