Is Birch ply suitable for external use?

[Doug71]

Local builder is after something to cover over some cambers and lintel fronts above some new softwood windows which can be stained to match the windows but it needs to be really thin so it doesn't stand forward of the brickwork.

I have some off cuts of 4 mm birch ply which would be ideal if it is okay to use externally, have googled it and not really got a clear answer?

Thanks in advance, Doug

 

[Woodmonkey]

I would say no, it will delaminate when the water gets in.

 

[nabs]

about 4 years ago I clad a corner post that separates the sliding door and window in my shed with exterior ply which, despite being carefully painted, immediately delaminated after the first heavy rain fall. I upgraded to marine ply and it has been fine ever since. I suppose the glue used must be different?

before redoing the corner post I stuck a bit of marine and exterior ply in a bucket overnight - results below (exterior ply on top):

 

[Beau]

I dont think it should delaminate as the glue is usually waterproof but birch is non durable and will need very good protection from the elements.

I used some birch ply for some signs for shows. Left unfinished and sat in the shed over the winter the ply went very mouldy with dark blotches all over it.

 

[johnnyb]

I've had a board of 18mm Russian birch outside for 5years. It's remarkably durable. Yes it won't look new but trust me its kept all it's strength and had not delaminated. Tricoya may be better but this would work.

 

[MikeG.]

Local builder is after something to cover over some cambers and lintel fronts above some new softwood windows which can be stained to match the windows but it needs to be really thin so it doesn't stand forward of the brickwork..........

Someone has made an awful cock-up of the detailing! Sticking 4mm ply over it will be compounding the cock-up.

 

[Doug71]

Local builder is after something to cover over some cambers and lintel fronts above some new softwood windows which can be stained to match the windows but it needs to be really thin so it doesn't stand forward of the brickwork..........

Someone has made an awful cock-up of the detailing! Sticking 4mm ply over it will be compounding the cock-up.

Yes it is not pretty, it's a barn conversion on a rough old place, the lintels are fitted in line with the brickwork courses some of which are a long way out of level leaving tapered gaps above the windows. The lip on some of the lintels are nearly flush with the face of the brickwork and some are set back, it certainly is not ideal.

Unfortunately at this stage it is a bit late to do much else. Their other idea was to stick some of that oak effect pvc on the front of the cambers/lintels but I think that would look even worse, I am picturing the look of disdain on your face MikeG as I am typing this .

 

[Woody2Shoes]

It sounds like there's no "right answer"! My suggestion would be a thin slice of oak, in preference to ply (whether BWP or not) - more durable, and visually more in keeping with the style of the building. Cheers, W2S

 

[Beau]

It sounds like there's no "right answer"! My suggestion would be a thin slice of oak, in preference to ply (whether BWP or not) - more durable, and visually more in keeping with the style of the building. Cheers, W2S

Yep this sounds like your best bet. Would have thought you could bond it to the concrete eliminating warping.

 

[Doug71]

Thanks for the ideas, didn't think of using solid timber, I have some off cuts of Accoya I can slice down which should be perfect.

Thanks again, Doug