How to fill the gap between architrave and wall?

[Russinating]

Everything in our house is wonky and I've got this gap at the top of the door's architrave between it and the wall. At the bottom the door lining is flush with the wall so there's no gap.



Bearing in mind I want to try and just wax/varnish the wood, rather than painting it white, how would I go about filling this gap? My initial thought was to attach a small piece of pine on the wall so that it lines up with the edge of the architrave and plane it in-line with the door lining. But I've just made that up so no idea if it'll work or what you're supposed to do.

Ta!

 

[Russinating]

Ok great. I've not really planed too much before, what's the technique for creating a gradual angle/difference in depth?

 

[Russinating]

Hold the infill piece up against the wall and line it up so that it is parallel with the architrave and touching the wall at the bottom. Then measure the top where the widest point is and transfer this to the infill piece. Then run a pencil down the wall from the mark you just made, so that it scribes the wall shape onto the infill piece. You may need to pack the pencil off the wall with bits of wood etc so it lines up with the mark you made.

Then simply cut along the line carefully with a jigsaw and then glue it in place with some PVA. Try and get a tight fit so you can just apply the glue and then tap it home gently and the slight pressure will hold it in place until the glue dries.

You can use a bit of double sided tape to hold the infill piece in place to make it easier to scribe the line.

I'm not sure I quite get this without some kind of diagram . Could I place the pine on the wall, get the mrs to hold it flush the whole way (it should be flexible enough to cope with the slight change in wall angle) and put a pencil flush on the door lining and run this up and down? This should give me the correct scribe no?

Bought a jigsaw today too so just need a bit of luck now...