Laying out and cutting a lean-to roof. Showing you the simple easy way to lay out & cut birds mouths and purlins for your chicken …
source
Cutting the Roof: Birds Mouth & Purlins | Chicken Coop Build Part 4
As we dive into Part 4 of our chicken coop building series, we’ll be tackling one of the most crucial aspects of constructing a sturdy and efficient roof: creating birds mouth cuts and installing purlins. This step is vital for ensuring your coop not only looks great but is also built to last through harsh weather conditions, keeping your chickens safe and comfortable.
Understanding Birds Mouth Cuts
Before we get into the nitty-gritty of cutting, it’s essential to understand what a bird’s mouth cut is. A bird’s mouth is a notch or cut made in a rafter. This cut allows the rafter to sit securely on the top plate of the wall, providing a firm structural connection that helps to distribute weight properly across the structure. Not making this cut accurately can lead to an unstable roof, which is the last thing you want for your feathered friends.
Tools You’ll Need
Before you begin, ensure you have the following tools handy:
- Circular saw or miter saw
- Measuring tape
- Carpenter’s square
- Pencil or chalk line
- Level
- Safety goggles
Step-by-Step Guide to Cutting Birds Mouths
Measure the Rafter Length: Start by measuring the lengths of your rafters. The length will depend on the dimensions of your chicken coop and the pitch of the roof. Make sure your measurements are accurate to avoid any issues later on.
Decide on the Roof Pitch: Typically, a 4:12 pitch (4 inches of rise for every 12 inches of run) is adequate for a chicken coop, but this can vary based on your local weather conditions. Ensure you decide on the pitch before proceeding.
Mark the Rafter: Using your measuring tape, mark the length of the rafter on your lumber. This will be your base measurement. From this point, measure up from the bottom at the angle determined by your pitch to mark the rise.
Create Bird’s Mouth Notch: With your carpenter’s square, draw the bird’s mouth cuts. These consist of two cuts: one vertical cut that will hold the rafter up against the wall’s top plate and one horizontal cut that will sit flat on the wall. Precision in this step is key; the cuts should be smooth and clean.
- Cut the Notches: Using your circular saw or miter saw, carefully cut out the bird’s mouth notches. Double-check your angles and ensure that you maintain a consistent depth across all rafters.
Installing Purlins
Once your bird’s mouth cuts are complete, it’s time to move on to purlins. Purlins are horizontal supports that run perpendicular to the rafters. They provide additional support for the roof sheathing and play a crucial role in load distribution.
Steps to Install Purlins
Determine Purlin Spacing: The spacing of your purlins will depend on the type of roofing material you plan to use. For heavier materials like metal roofing, purlins are usually spaced about 24 inches apart. For lighter materials, you may opt for wider spacing.
Cut Your Purlins: Measure and cut your purlins to the appropriate length. They should extend across the rafters and hang off the sides just enough for proper water runoff, but not so much that it poses a risk of breaking.
Attach Purlins: Position the purlins on the rafters, using a level to ensure they are straight. Secure them with screws or nails, ensuring they are tight and stable.
- Check Stability: After all purlins are installed, give everything a gentle shake to check for stability. Any signs of warping or movement should be addressed immediately.
Final Touches
With the bird’s mouth cuts and purlins in place, your chicken coop roof is on its way to being strong and reliable. Next, you’ll want to cover the roof with your chosen material, ensuring it is adequately sealed against weather and moisture intrusion.
Conclusion
As we conclude Part 4 of our chicken coop build series, we hope this guide on cutting birds mouth notches and installing purlins has provided you with the knowledge and confidence to tackle this vital stage. Stay tuned for our next installment, where we will focus on roofing materials and finishing touches to create a comfortable and secure home for your chickens. Happy building!
