Exterior wooden window painting tips

[KenJ]

Hi all,

I have hard wood windows in our house which are all in good condition (circa 6 - 8 years old) and painted grey. In the last year since moving in I have repainted all of them and for the most part, they still look fresh. However, I've noticed some of the paint is flaking off, in particular around any hard edges without a radius.

Can anyone give any tips on anything I can do to stop this, or, is it just a case of needing to sand down and repaint these specific areas more often (say every year).

For information, I'm using Johnstone's exterior paint, waterbased, which seems to receive good reviews from what i can see. I don't really want to change, as I've had this colour matched to the existing paint.

Any tips or help appreciated. Thanks

[Lotobear]

I got through your first sentence and thought to myself - 'you've used water based haven't you' before you later confirmed it.

The, IME, answer is to use a high VOC paint.

[Wacky Racer]

Yes, I would never use water based paint outdoors, oil based all the way.

Water based is fine for certain areas indoors, brushes wash out easily in water, it goes on nicely, but chips easily, for instance on skirting boards if a hoover knocks against it,

[wolfracesonic]

If yo do repaint, get some coarse sand paper and put a radius on all the sharp arrises, no paint adheres well to a sharp corner.

[Lotobear]

Another thing I've found is that paint prefers softwood to hardwood - aluminium primer is the best foundation on hardwood IME

[shtu]

I'm repainting a bunch of exterior windows right now.

Oil-based paints all the way for me too. It won't last forever, but I find it much tougher than water-base. The Leyland stuff out of Toolstation or Screwfix seems fine, and it's not expensive.

I go for separate primer, undercoat and topcoat, rather than combined primer/undercoat. To my mind, that reduces the chance of thin spots in a single coat being a problem.

[Russet Grange]

Zinsser AllCoat is water based and I rate it very highly. So do many others apparently.

[POIDH]

I used Johnstones on all my exterior wood on south side of the house - it lasted OK, but it was an every 5 years quick rub down of loose bits and recoat.

The front door was treated to Zinsser All Coat saitin (and was plastic, not wood) and it lasted 10+ years and looks superb...I have since used Zinsser on anything outdoors.

[Milkyway]

Hammerite...blurb says it can be painted on raw & undercoated wood.
(Apparently... It's a bit thicker than 'normal' paint.)

NB: I did see a product on YouTube... It's a clear coat solution that can be used to seal paintwork, brickwork, concrete etc.
(Don't think it's cheap though)

Edited by Milkyway on Friday 14th August 12:02

[Stegel]

Up until 3 years ago, our house had a mixture of original, 1929, windows with softwood frames and oak sills, and hardwood (Iroko) windows in the extension built 20 years earlier, all painted with Jotun Demidekk water based paint. The original windows had been stripped back to bare when we moved in in 1993, primed with the Jotun tung oil primer, and repainted with the Demidekk a couple of times. We stripped the old windows out 3 years ago and replaced them with new Iroko frames, all painted with the same system although the Jotun primer is now water based.

There has never been any peeling, and redecoration after original coats is a wash down and straight on with the top coat. I would never go back to the old high-VOC paint systems, both due to longevity and the amount of prep required.

I doubt the OP’s issues are to do with the water based paint but more likely incompatibility with whatever was on before or inadequate prep.

[jmn]

I've always used Bedec Barn Paint on my exterior wood and it has lasted very well indeed.

[Square Leg]

As a pro decorator of some 40 plus years, I generally used to use Sikkens products externally.
On my own house I use Sikkens Rubbol Satura - it’s expensive but does a bloody good job.
My north east facing windows are near perfect some 7 years since the last painting, the south facing needed re doing last year but won’t get done until next spring now, so the paint can last if done properly.

As someone above said, you need to slightly round off the edges (technical word is arris..) for best adhesion.

[Square Leg]

Lotobear said:

Another thing I've found is that paint prefers softwood to hardwood - aluminium primer is the best foundation on hardwood IME

Absolutely this - Ali primer is the dogs but sadly many (and I include pro decorators) don’t tend to use it.

[lj04]

Zinnser or sickens both do great water based paints. Bedec barn paint on bare wood lasts ages when you give a diluted first coat. Whatever you choose give the windows a good rub down

[KenJ]

Thanks all for the replies, really helpful. I'd already bought a new tin of the Johnstone's paint, colour matched to the original. Given this, I focussed more on the prep, and in allowing the frame to fully dry for a few hours after cleaning prior to applying the paint. I then stuck firmly to the timing before applying a second coat. Hopefully this will make a positive difference.

Thanks again

[Sir Bagalot]

I've used Sadolin Superdec in the past with great results, although will need three coats