Birdsmouth Template – green oak barn

Wednesday 3/2/21

Today was assigned as a “research and thinking” day. I also did a couple of hours on ColaLife. I needed to know a bit more about hip roof construction before proceeding. A key find in this process was a birdsmouth template that I spotted in the background of this video – How to cut hip rafters – by Robin Clevett. I had to take some screenshots to absorb how it worked as it wasn’t described.

By 2pm I was climbing up the wall and needed to get out. So, a set about making a template. It took me three attempts to get it right but here it is.

Birdsmouth template - 1

These are the elements of it.

Birdsmouth template annotated

You start by aligning the template with the plumb cut of the foot of the rafter and the rafter’s underside. You then run your saw along the seat cut guide until it hits the saw stop.

Birdsmouth template - 2

You then turn your saw through 90 degrees and run it along the heal cut guide. You need to pay attention when doing this as there is no stop and you can overrun if you are not careful.

Birdsmouth template - 3

You then complete the birdsmouth by hand with a saw.

This is going to speed up the cutting of the rafters a lot and make them more precisely the same.

I also looked for examples of green oak hip rafters and came across this page on the Castle Ring Oak Frame website. It had these very relevant images. This is how I think I will do the hip rafters except they won’t be chamfered as they will have softwood hips laying on top of them.

Green oak hip rafter

I also think the lower joint will look a bit like this, although I will try and finish the bottom edge of the hip rafter level, or higher, than the underside of the wall plate.

Green oak hip rafter - bottom joint

This other picture from the Castle Ring Oak Frame website shows a very similar approach to the roof structure to the one I will be using. The only real difference is that I will be laying a softwood ridge beam and hip rafters on top of the green oak ones. Also, I’ll be using standard treated softwood – it looks like they’ve used very beautiful larch in this example below.

Roof structure

I will proceed, saw in hand, with more confidence tomorrow.




This entry was posted in DIY, Green Oak Barn. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *