External Bi Fold Door Finish

[mikehow]

Hi all

Just wondering whether anyone would be able to shed some light on what finish commercial companies use for external oak bi fold doors?

The house we moved in to earlier in the year has a set of bi folds fitted, unfortunately the external doors have weathered badly particularly on the sill and bottom of the doors and the finish is cracking and flaking.

I've spent some time today removing the flaking finish, sanded flat and applied some Osmo wood reviver to try and clean up the wood which has been reasonably successful.

I've applied a couple of samples of Osmo UV Protection Oil in Clear and Oak tints to try and find a colour match, however when applying the samples I noticed that the protection oil is really thin and wouldn't really allow me to build up layers to match in with the existing finish.

Would I be better with a varnish of some sort? Maybe Yacht varnish instead?

 

[Trevanion]

Something from Sikkens will do you well.

 

[johnnyb]

sikkens or sadolin. they aren't really clear as they must filter out UV. they are at best muddy. I'd suggest full paint using sandtex flexi but satin. at least on the outside. it will last and cover a multitude of sins.

 

[johnnyb]

just checked it's called 10year exterior satin also matching undercoat primer.

 

[RobinBHM]

Almost certainly the doors will be finished with a waterbased spray system, either Teknos, Sikkens, Sigma or even Morrells etc

the most common system is a tinted based coat and a tinted top coat.

very hard to repair and get and film thickness

cheap oak bifolds are veneered as well.

 

[mikehow]

Thanks for the quick replies.

Having done a few searches definitely looks like a Sikkens light oak.

We’ve got a Brewers locally so I’ll pop down Monday.

What a great forum

 

[mikehow]

Well after a trip down to Brewers today, I came home with some Sikkens.

Testing it out it side by side with the Osmo tester, it still looks a way off colour wise to what is on currently.

Looking a bit harder tonight its definitely a varnish finish as its cracked and hazed on another door, obviously matching in a varnish and micro porous stain isn't going to work particularly with the consistency of Sikkens.

With 9 doors to do, it looks like I'll be busy over the next few days with a carbide scraper getting rid of the existing varnish.

 

[Trevanion]

Just be aware that the Sikkens will probably make the doors significantly darker than the existing finish, but it's basically a fool-proof finish and lasts a very long time. Apply fairly liberally with a brush, leave for a few minutes and wipe the excess off with a cloth.

A member here, RogerM has done some excellent weathering tests with Sikkens, Sadolin and Osmo on various timbers:

Sadolin Ultra vs Sadolin Classic vs Sikkens Filter 7 Plus

External iroko - Osmo UV Oil or Sikkens Cetol Filter 7 Plus

 

[mikehow]

Thanks - I'd spotted the second link but hadn't seen the first one which is really interesting.

The area I've applied Sikkens to is significantly darker hence my reticence to redo all the doors (10 in total) until I'm comfortable with a colour match somewhere near to the original.

Managed to track down the manufacturer of the doors, and spoke to their aftercare team today.

Basically they are saying they have their own branded micro porous finish which is Sigma Sigmawood, otherwise go with Sadolin or Sikkens.

Apparently they don't use any lacquer top coat its just a by product of the micro porous finish which gives it a milky/translucent finish.

Cost wise the aftercare product is pretty much in the same ball park as Sikkens so erring on the side of going with this to save the hassle of stripping the doors and ensuring we retain any remaining warranty on the door.