what angle do I have to cut ? Please help

[MamaChic21]

I looked at this site and it says to cut 45 degree angle to make an A-frame roof for 8x8 shed. Well I'm building 8x8 coop so thought no problem, same roof ! I've tried cutting the 2x4's at both sides at 45 degree angle and it was just too high, more then 4 ft. I want it some where like 2ft max. What angel should I cut the sides of the 2x4's for framing the a-frame roof ?
http://www.mybackyardplans.com/gablestorageshedroofframe.php

 

[farmer_lew]

Ok, here's how I do it. May not be how everyone else does it, but it works for me...

How steep do you want your roof? When I built gryeyes, I did a 2 ft rise and it was very steep and hard to put the corrugated roof on because it was hard to get footing. If it doesn't snow where you are, I'd recommend 1 ft. If it does snow, 2 ft would be better, though.

First...install a "kingstud" on top of the top plate to hold your ridgeboard. For a 1 ft rise, the king stud should be 8 and a half inches tall. The 2x4 ridge board will make up the rest of the 12" height.

Second...install the ridge board across the top of the two kingstuds.

Third...determine the length of your rafters. This is where math comes into play. You need to use pythagoreans theorem. A squared + B squared = C squared. (A = rise, B = run, and C = rafter length) You will need to add however much overhang you want to this measurement. The part of the rafter that hangs over the wall is called the "tail" of the rafter. For gryeyes coop, which had a 2 ft rise, the rafter length was 4 ft 5 and 11/16 inches. I rounded the length to 5 ft to allow for the tail. With a 1 foot rise and 4 foot run (the run is half the total span) the rafter length comes out to 4 ft 3 1/2 inches. Add the length of overhang you want and, PRESTO! you have a complete rafter. Some people will say to make a cut called a "birdsmouth" to attach the rafter to the wall. I use rafter ties made by Simpson Strong Ties. Makes it easier and quicker. You can get them at HD or Lowe's.

Fourth...for the plumb cut, where the rafter ties to the ridge, what I do is hold the rafter in place where I want it so that the topmost corner is flush with the top corner of the ridgeboard on the side that the rafter is going to be on and make a mark where they cross. Cut that line and there's your angle. Now use this rafter as a template for the rest. It is best to cut them as you install them, in case you need to make a trim here and there.

GLOSSARY OF TERMS: (Not in alphabetical order)
Rise: The height of the roof from the top of the wall to the peak.
Ridgeboard: A board that supports the peak of the roof, to which the rafters are attached.
Kingstud: A short board attached to the top of the wall framing that supports the ridgeboard.
Span: The total distance across a structure from one side to the other.
Run: Half the distance of the span.
Rafter: A board that is attached perpendicular to the ridgeboard and to the top of the wall framing to support the roof.


If I left anything out, or COMPLETELY confused you, PM me.



~Farmer Lew

 

[patandchickens]

Yeah, 45 degrees is WAY steep for a roof -- that is a 12:12 pitch. Roofs are typically more like a 3:12 pitch or thereabouts (meaning, it falls 3' vertically for every 12' horizontally)

Can I make a suggestion?

Put the coop walls up. Make sure they are REALLY VERTICAL.

Then get a helper on a ladder. And a 2x4 the size you'll be using for your rafters (or trusses or whichever wya you're supporting the roof).

Have the helper stand behind the coop (or in it), and hold the 2x4 up as if it were a rafter, propped on the top of the wall the way it will lie.

Stand back and look at it. Direct your helper ("up more! no, not so much. down a little more. up a little more.") til you have it so it looks right to your eye. Remember that a flatter slope will have more issues with snowload and leaking; a steeper slope takes care of those things better but is more expensive to build (beyond a certain point anyhow) and catches more wind that can stress or tip the structure; so you want a happy medium.

When you have picked a slope that looks reasonable to you, say "Ok, now hold it right there!!!"

Go to the end where the tail of the 2x4 hangs over the sill of the wall. You will need to have a long straightedge (even just a 2'-long scrap of really straight lumber will do) and a pencil. Put the straightedge against your wall, extending up alongside your held-in-place rafter. Trace the line where the vertical straightedge crosses the rafter.

That is your cut angle.

(It is probably not your cut *line*, unless you have also instructed your helper to hold the rafter with the right amount of overhang over the wall -- but you can use a protractor to copy that angle to where you DO want the cuts.

The cut will be the same angle at the peak of the roof as at the rafter-tails, assuming you want vertical fascias which most people do.

There, no math, no vocabulary, just 'hold it up til it looks right and mark it'

Seriously, it works fine

Good luck, have fun,

Pat

 

[MamaChic21]

Thank you Farmer Lew and Pat

Unfortunately, this work mission is a solo. I don't have anyone else to help me. So far, no matter what angel I cut, it is too high. I put up only 2 walls for now. Including the platform and wheels, it's approx 1ft off the ground. The side walls 4ft and I would like the roof to be approx. 2 ft, so total 7ft. I don't want to go higher then that.

 

[farmer_lew]

Looking good so far!

Well, you could build trusses on the ground, but you would need help to put them up. In your case, being a solo job, the best bet is to frame it in place. You will need a ladder to reach the peak. Pat's suggestion is a simplified version of what I said. I can't think of an easier way. You will have to come up with a way to hold the boards in place while you eyeball the angles and such. You could use a scrap piece to prop it up temporary, until it looks right, and you can scurry up the ladder to nail it place.

OR! You could do a mock up on the ground. Lay out some boards with the dimensions of one wall. Lay out your rafters until the angle of the roof looks right and make your marks. Then, before you cut it, double check by propping it up on the coop and eyeball it. If all looks good, make the cuts. I would still use the first one as a template for the other rafters, though.

Good luck!

 

[patandchickens]

It doesn't matter if you're doing it alone. You can prop it up there with some other lumber, can put a single screw or nail to connect them so you have a "hinge" to work with. Or as farmer_lew says you can mock it up on the ground to see what looks right.

BUT GET THE OTHER TWO WALLS PUT ON FIRST!!!! RIGHT NOW!!!! Before you even think about roofs!! Seriously!! Otherwise the existing two will fall over and damage themselves, either while you're working on it or overnight!!!


Pat, who grew up with her father telling her sternly that (when I did htings like what you show in the pic) "that is an inherently unstable configuration" -- and you know what, he was RIGHT. You don't want to lose what hard work you've already done!

 

[MamaChic21]

Thank you Pat and Farmer Lew, I will do my best

 

[Arielle]

It's looking really nice! Good job!!

My husband builds all my barns alone--always says he doesn't need any help--- you can do the roof by yourself, you really can. Find what works for you, temp nails or screws.

Our house is a 12 pitch--we never cleaned it off this winter even while houses and barns were going down around us; BUT DH was cleaning off the barns which have a much lower pitch. It's complicated. Just don't build a flat roof in snow country! And put in all the nails in each stud to attach it properly to the ridge pole and walls. DH puts in 5 nails at each end, as I recall.

Do show us the finished building!!!!!

 

[MamaChic21]

Quote:
Thank you Arielle

I will definately post the finished product

 

[PapaChaz]

both Lew and Pat, are very knowledgeable! Lew must be a whole lot closer to just out of high school to be remembering all that geometry! LOL anyway, my garden shed is 8 x 12, with the roof spanning the 8 ft part. my coop is 6x8, spanning the 6 ft part. it's dark out right now, but i can get you the measurements and some pictures tomorrow. i think the roof peak is about 2 ft above the wall, that's what you're wanting right? i'll get measurements and angles for you, but i did fix mine with an overhang in front....look at my coop page, i think there is a pic of the garden shed on there somewhere. i did the coop so it would look the same, so it's proportionately equal just smaller. i know i did the coop roof at 25 degree angles, and i built trusses instead of rafters. either is fine, the chickens roost on the crossbeam of the trusses though, now i wish i'd done rafters, LOL

good luck, will get pics insidethe shed, measurements and angles after church tomorrow!