External paintwork blistering above imprinted concrete drive

[adeasha]

I had an imprinted concrete drive laid a few years ago. After a while I noticed the external paintwork on the stone window cill had bubbled. Despite stripping and repainting, the paint still bubbles. Can anyone suggest a solution? I think some acid from the concrete stain has got onto the cill. What can I use to neutralise it?

 

[TheDec]

Did this problem occur in anyway before the drive was laid.

Dec

 

[adeasha]

No, I had a crazy paving drive before with no problems with the paintwork.

 

[TheDec]

Scrape off the loose paintwork and using a stiff bristle brush scrub the cill a few times with warm water, when dry apply a thinned coat of your paint, It may be all they need.

Dec

 

[adeasha]

Thanks for the advice. I'll give it a try!

Anne

 

[misterhelpful]

I would have thought that, as the drive was done a few years ago, any acid/chemical residues would have been washed away by the rain by now.

It's a heck of a long shot, but is it possible that the new drive has bridged the house's dampcourse allowing water to wick up the wall and somehow escape through/cause efflorescence within the cill?

 

[TheDec]

The op said that the cill was stone and therefore very porus, the natural capillery action would have easily been capable of absorbing the acid or indeed whatever it was rather deeply. If a quick scrape and repaint was undertaken there remains the possiblity of further breakdown of the paintwork.

Dec