UKH

One of the jobs for the front of the house is to replace the old barge boards at the top. 

What is the best way to ensure my two cuts for the point at which they intersect at the top is correct?

Thanks

Simplest thing would be to clamp the old board on top of the piece to be cut and use it as a saw guide.

You'll also need to think about how you make the cut. A chop or mitre saw will give the neatest result, unless you are very handy with a panel saw.

Get a pointy thing to put in front of the join to hide the gaps 😀

https://www.canopyproducts.co.uk/shop/decorative-heritage-barge-boards-redw...

Measure the angle?

A couple of ways:-

1.  Measure  a length of your new barge boarding measured & cut from the lowest point to the apex.

Clamp it, screw it or lightly nail it in place.  Using a level (or if you are confident) your eye and scribe a pencil line vertically down from the apex.  Unclamp, unscrew or remove the nails take it down cut it following the scribe lines.  Do the same for the other side.  

(To save taking a whole bit of new timber in place you could simply do it with a bit of card!!! then transfer that onto your new boarding)

2.  Remove the old boarding and use that as a template to cut the angle at the top (and bottom). transfer to the new bit of wood  with a sharp pencil.

If you don't have chop saw, use  a Jig saw, if you don't have jig saw, buy your self a new saw and cut down the pencil line.   If its a bit wobbly don't worry.  Buy or make something like Wimlands has mentioned.

 

Looking at your photo, it looks like a good rub and repaint might be enough. Maybe a bit of wet rot on the corners to repair? (difficult to see). Have you been up to confirm they need replacing, or could they be repaired? Not wanting to teach you to suck eggs but I have seen timber that looks awful and when you get up close and poke it, it's OK and just the paint that looks awful.

You want a nice big diamond feature at the top. Should cover the dodgy cut nicely!

https://www.amazon.co.uk/Silverline-783421-Steel-Finder-Protractor/dp/B003T...

Cut it square, temp screw it on, run a spirit level from the apex and draw a perfectly vertical line for your cut.

Sliding bevel, cost a few pounds 

Thanks everyone for the helpful responses. Seems like a number of ways. 

Much appreciated. JW

My porch window looked awful, and some of it was, in my poking a screw driver through the frame to inside my porch, but that repaired okay with some digging out of the rot and some rot hardener and filler. Filler hides many sins I found, after having to break in through the small top window and glue the wooden frame back together again. 

I'd use the old board(s) as a template and squeeze some flexible caulk into the seam before closing it up.

If you need to mark it up without the old boards for reference, cut them oversize and approximately right, temporarily fit them with a small gap, place a ruler with parallel edges over the gap and scribe the joint faces.

jk