Panelled door paint keeps cracking

[phatboy]

Hi,

I have painted my garage hardwood door. I think it's about 60 years old, and is 'real' panels, not like modern routed out ones. It was previously I think protected with varnish, but this had long gone when I moved in.

I caulked the joints as they did have a bit of a space. I then primered with Zinnser Bullseye 123 +, and then 2 top-coats of Dulux Trade Ultimate Opaque.

It soon cracked, so I assumed the panels had moved in the heat (paint is antharcite coloured), and so re-primered then top coated the affected areas. But it happened again.

Any suggestions? Is there something I can use on these joins to prevent the cracking, or is it just the way it is with that type of door, and my choice of colour?

Thanks
Tim

 

[opps]

Caulk doesn't have enough elasticity. Use a MS polymer (eg Sixaflex, CT1, etc).

Although they can be painted over (unlike silicone) you will need to hit them with waterbased undercoat first. If you apply oil based paint over them, the paint will be tacky for weeks.

Another advantage over caulk is that they do not shrink back. On the job I am doing today, much of the caulk on the top of the skirting boards had cracked, I chiselled out as much as possible but cannot remove all of it. I could re-caulk them but I am aware that as it dries it will shrink back less where there are bits of the old stuff that I couldn't remove. With MS polymers, it will dry exactly as it did when you applied it.

They do however cost more and are more difficult to clean up. You might need to buy some decorators wipes.

 

[phatboy]

Caulk doesn't have enough elasticity. Use a MS polymer (eg Sixaflex, CT1, etc).

Although they can be painted over (unlike silicone) you will need to hit them with waterbased undercoat first. If you apply oil based paint over them, the paint will be tacky for weeks.

Another advantage over caulk is that they do not shrink back. On the job I am doing today, much of the caulk on the top of the skirting boards had cracked, I chiselled out as much as possible but cannot remove all of it. I could re-caulk them but I am aware that as it dries it will shrink back less where there are bits of the old stuff that I couldn't remove. With MS polymers, it will dry exactly as it did when you applied it.

They do however cost more and are more difficult to clean up. You might need to buy some decorators wipes.

Thanks for that, I'll try and pick some up at the merchants. I'll coat it with Zinsser Bullseye 123+ again. I think that counts as primer & undercoat?

 

[phatboy]

Well, 3 weeks after applying some CT1 to the areas, re-priming with Zinsser Bullseye 123+, and 2 top coats everything is looking great - no cracks have re-occured even when the door has spent the day in direct sunlight.

I have most of the tube spare, and there are a few PVC doors in the house that keep cracking at the joints with the walls, so I'll be using CT1 on these areas too to try and resolve, when I get a chance.

Thanks for the top top opps!!

 

[opps]

Thanks for letting us know how you got on. Best of luck.