Architrave won't sit flat on window frame

Hi,

I'm near the end of a long owner-builder project and I have a number of windows that need architrave.

A chippie installed the window frames, the plasterer has done the plasterboard and now I want to fix the architraves myself. I've bought a stack of 70mm mdf architrave. My problem is that the plasterboard is not flush with the inside of the window frame, but sits about 1 to 2 mm proud of the frame. So the archs won't sit flat against the frame that I want to nail them to.

I could...

1. put a small amount of packing at each point where I nail the arch to the frame and then no-more-gaps between the arch and the frame, or
2. run the archs over my router table to shape them so they fit flush on the frame but still clear the plasterboard

:confused: what would you do?

Andrew.


PS I've read one or two threads about the "quirk", so I understand that I should set the arch slightly back from the inside edge of the window frame
PPS I've also read quite a bit about the benefits of breathing mdf dust, but I have the vacuum cleaner, triton sucker-bucket and a decent respirator so I should be ok :)

Seems as though the windows have been installed incorectly, as you suggested run them over the router table this will give a more profesional finish, no more gaps type of products despite what the maufacturers claim will crack over time (in my opinion)

BTW if you have adecent respirator you should be OK

It it were me, I reckon I would plane down one edge of the architrave 1 or 2mm and have 'em sit flat. Of course I know MDF can be a bugger, :( that's why we don't use so much of it over here. Or anyway I don't.

The windows would have been installed correctly, it would be just the plasterboard not sitting flat on the stud, happens all the time. What you can do is cut the plasterboard back a little bit so the Arch will sit a bit more flatter on the surface, and then you can nail it to the window reveal and sort of push the arch back against the plasterboard and nail it to the studs.

Or, has the other Carpenter nailed off the window frames?

Brick veneer or timber frame? BV the windows should have been set correctly to allow for the 10mm plasterboard. If its timber frame & the windows were set to be flush with the cladding there can be an inevitable variation of up to about 4mm due to nothing more than the normal differences in milling, framing, & materials. The way to fix this is to back off (plane) the portion of the arch that sits against the plaster so it can then sit correctly in the same plane as the window reveal. Sit a rule or even a piece of timber against the head reveal & then the sill reveal & push it up to the plaster. You will get an idea of how much the plaster protrudes over the length of each stile reveal & transfer this amount to the arch, then plane away. After a few trial fits you'll get it right. You can to some degree feather the plaster as Shaun suggests, but if you're using a profiled arch this will introduce a compound angle & it all gets very messy from there. Having said this, you can get away with a lot more variation if its a paint finish.

I had a similar problem and planed the window frame down. It worked fine except at the corners where the plane was going across the grain of the other piece of reveal. I ended up having to fill a few uneven bits. probably my awful skill levels but I wouldn't really recommend planing the reveal down as a way to go. However, a lot healthier than routing mdf.