Let me show you how I got the rafters framed up on the coop. This bit of the design required plenty of telephone conversations, wrestling with hypotenuse and getting my head around the concept of the rise and the run.
To design the coop roof I pictured what I wanted the slope of the roof to look like. I knew the width of the coop and the height of its walls, so I drew it all on paper. Then, I drew it all in SketchUp, which let me measure things out after, so I could play with information I had, incorporating what I’d drawn, til I had answers. I sent the 3D drawing to my father to confirm that it all worked out mathematically. I can tell you the following bit of information that he sent back was intimidating, but for those of you who like trigonometry, here you are:
Based on the roof angle (40 deg) and the width of the coop (60"),
one can calculate the rise as follows:
Tangent (slope angle) = y/x
Y is unknown (Rise)
X is 60" / 2 = 30" (Run)
Y = Tan (40) * x
Tan 40 deg is equal to: 0.83909963117728
Substituting values and solving for Y:
Y = (0.83909963117728) * 30
Y = 25.17298835318394
Make Rise Y = 25"
Quite. 25″ rise and a 40º slope is what my original paper drawing expressed, but it’s best to double-check with a trusted mentor.
I decided not to build trusses (triangles) flat on the floor of the coop, before putting the walls up. Instead I framed in a ridgeboard which rests on one 2×4 with two more sandwiching it, supported by the front and back walls. Critical to have a good level to hand, I have a tiny one and a standard large one, both very old but trusty. That sandwich piece, including the height of the ridgeboard, would be the rise. The children figure it looks like a lunchbox at this point.
Then I cut rafters (thanks to the kindly loan of a neighbour’s mitre saw, no more handsaws for all this cutting!) and notched them with a birdbeak which sits on the top of the wall. Simple strength.
Once the rafters were secure (I drill pilot holes and use deck-screws) I built the verge, the overhang, on each end. Rainy winters on the Pacific require it. You can see that the verge is anchored by a couple of flat pieces that attach to the main rafters, see? I laid one rafter flat to support these pieces. I love finding out how things work.
I’d planned the ridgeboard’s length to allow for 12″ of overhang on each end. Now it looks like a little house.
The roosting bar design was a little bit inspired (see below). Now, there are cross-ties and there are chords, they complete that triangle from wall-to-wall or up higher. These give the structure of roof and walls strength, integrity. I decided to use these pieces first structurally, then practically, as roosts, and finally, socially, by staggering the height of the crosspiece, to give the flock a framework to express their social order. Each night we see who roosts at which height, and in which direction, based on pecking order. Yes, those are railings from the 1950’s house demolition.
Or, for another way to look at it all, a peek at my journals from that week:
the girls helped to mind the chicks, they love the playground under the maples, though i must enclose the area outside my potatoes. i fixed my problems after some tears – broke a drill bit, things were wonky. i managed to get things levelled, plumb, and my tall girl helped me to pop the ridgeboard in – yay! how grand! it looks pretty funny, but then i sorted through a couple of videos and worked through plain old fear, and i got the rafters worked out, one of them is up! not attached, but just there — and that was a moment of huge satisfaction. hypotenuse, kiss my -! i am so happy to have pushed through, i really thought it was going to fail. well, i’ve got it now, and i’ll cut from my template and then work out the supports for the verges.
i actually threw up my hands and closed up my writing desk, it is right beside the brooder and getting so dusty! i threw a dust cover over it. i give in! when the chicks move out i’ll return to it.
i made a mistake, and needed to raise the ridgeboard ¾” and cut the birdbeaks to my original plan. that worked, and i’ve cut 6 pieces for the support for the overhang gable. it has been mad, as it is all being done with small children visiting. the lawn needs mowing, and the thistles need to be pulled, and a front bed cleared of flowers before a tree felling.
cool and a bit windy today, but i was glad for it. i made great progress with the coop. i attached the middle rafters and with a chat with my dad and some more mad calculations i figured out the overhang. the verge. when a friend came we got it put together on the front! i am so relieved! very pleased. it will need the same again at the back. my friend was just brilliant, so practical and enthusiastic.
little birds were well and went to sleep easily. i have the heat lamp on, still. they’ve weeded the patch under the maple very well, and i think i’ll move them to a spot under another bush further on, tomorrow, where i can watch over them as i build.
i had a brilliant idea that came out of a conversation with my dad – to use the chords as roosting bars, yes, but to stagger the heights, descending toward one end of the coop like a ladder. i’ll end at wall height, and the highest must still have headroom. so that’s finally sorted. good. the next steps, then. i’ll be attaching the back gable verge next, and securing all of it, yes. i’ll need to add supports to the posts.
i’ll not be putting wire over soffits, instead i’ll just close them up and plan to keep the back gable screened.
i’m quite tired. and sore, from falling over on to a rock! slipped in the rain while carrying a couple of chickens, pippin and blue. i saved them, but not, literally, my own ass. ah well, more bruises.
i took on the north gable verge, banging my head repeatedly, in the rain, swearing. i did it alone, save two minutes from our tall girl. clamps ‘r’ us. the chicks were happy in their enclosure all day, and i’m glad to have had help to move them inside. now the framing is complete, topping out ceremony traded for an epsom salt bathe.