Exterior timber mitres opened up

G

Gossamer

Joined
2 Dec 2015
Messages
444
Reaction score
18
Country
United Kingdom
Hi,
I’m repainting some exterior panelling and some of the beading mitres have opened up, some 4mm or so.
The panelling is 15 years old so I assume shrinkage is to blame.
How do I rectify this as it looks awful.
Thanks.
 
Replace the beading. No other way to rectify without bodging. Presumably it has shrunk along the length and opened the outsides of the mitres more than the insides. Possibly beading is a different species to the door framing? (e.g softwood beading on hardwood framing)
 
Last edited by a moderator:
JobAndKnock said:
Replace the beading. No other way to rectify without bodging. Presumably it has shrunk along the length and opened the outsides of the mitres more than the insides. Possibly beading is a different species to the door framing? (e.g softwood beading on hardwood framing)
Click to expand...

Ideally I’d replace but not viable in this instance. There are different species in there so I think you’re right, they’ve moved differently.

blup said:
I have used a two part epoxy filler on a garage door frame, the filler dries slightly flexible and can be sanded and painted over:

Timbabuild Timber Repair System - Chemfix Timbabuild EHB60 Epoxy Resin Filler 400ml (Was EHB4) | Sealants Online

Blup
Click to expand...

That looks good but it needs to be done tomorrow and that isn’t readily available from the usual places like screw fix etc. Might have to two part filler it and hope for the best…..
 
TBH it will probably crack over time - if your beads have shrunk that much there is plenty of opportunity for it to move again in the future.

Were the beads left unpainted for periods?
 
JobAndKnock said:
TBH it will probably crack over time - if your beads have shrunk that much there is plenty of opportunity for it to move again in the future.

Were the beads left unpainted for periods?
Click to expand...

After feedback I'm thinking filling will be least bad. I would have thought most shrinkage would have occurred already....?

Yes they were neglected (not by me!) so this is a rescue job.
 
Timber is a natural material - it moves (swells and shrinks) constantly, so it isn't inert and it can always move in the future, and if it does the joint between the filler and timber will crack. It's that simple
 
If it's an internal bead it should be scribed, not mitred.
When the wood shrinks the gap is about half, and in a less noticeable direction.
Can't find a good pic , but:
400px-ScribedJoint.png

Look carefully at the front joint.
The piece on the right is square ended, it's cut flush with the rear face of the piece on the left.

You either
  • draw round (scribe) the left (ie front) face of the piece on the right, on to the piece on the left.
  • cut the left piece (coping saw)perpendicular to the left piece's front face, along your line. It butts up to the wiggly front face of the right piece.
or
  • put the left bit in a mitre box and cut a 45º mitre.
  • The front surface 135º cut line, is your marker for where to cut the bevel off perpendicular, with the coping saw.

I know these aren't beads, but the same applies even if you've only got a triangular bead.
 
@Justin Passing - I think that's an American text you are quoting, The saw you use may well be a coping saw, but the joint is called a scribed joint in the UK. There is also a far faster, easier and more accurate way to do it - one piece is installed square edged, the other piece, which is to be scribed, is sawn to a 45° bevel, the edge of the bevel is highlighted with a 2B pencil and the scribed cut made with a coping saw putting a degree or two of back bevel
clearance onto the cut to ensure a good joint. Having served my time with a traditional shop fitters we were told that beads on interior panels you can generally get away with (especially now we have Mitre Mate) but that large exterior panels (the sort you sometimes used to get on pub frontages) require something like a lapped mitres or a scribed joints as you say to keep them from opening up. It's been a long time since I needed to do one, though, but thanks for prodding my memory
 
You must log in or register to reply here.
Back
Top