# MDF baseboards or any MDF



## SunHouseProperties (Feb 19, 2015)

Was looking at bottom blisters and bottom lifting of paint from repaint baseboards and it was running 50% of common hallways. I ran flat edge along and knocked smooth then ran sand sponge to smooth. I thought of the cause and came up with : must have been sprayed and the water in the paint went under and soaked the unprimed short under face , where the baseboard sits to the floor. Just like brown paper behind top white layer of drywall will bubble and lift if just painted over. I could just run very smooth caulking to seal these millimeter edges of brown paper so they wont lift with my top coat,,, so anyway when spraying out baseboards angle down and not straight on so as to not mist too much on unprimed underface. I like finishing new basebaords before install then fill holes and touch up.


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## RH (Sep 7, 2010)

Don't think I've ever seen unprimed MDF. Poorly primed, yes, but never completely unprimed. But even then, I think that you shouldn't have issues with the water content in latex/acrylic product causing this - sprayed or otherwise. I would tend to think that if the floors are a hard surface, too much water has been used to clean them and it was allowed to seep under the baseboards. If carpeted, too much water applied and then not extracted with a carpet cleaning machine (DIYer type?) could possibly cause it. Usually though, water related MDF damage is confined to bathrooms, and then it's typically (but not always) nearest the tub/shower units.


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## philcav7 (Sep 12, 2013)

How old is the baseboard installation? 

I too couldn't imagine a WB paint to cause the edge to lift. WB finish on raw mdf will absolutely cause a gritty/raised texture, but not so much as swelling. 

All off the shelf mdf base trim that I have seen had the typical primer applied to all surfaces.

If the swelling is a result of moisture, I would suspect it has nothing to do with the top coat applied or overspray.

Do you have any pics that you could share with us?


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## SunHouseProperties (Feb 19, 2015)

Ive painted already so the pics look awesome,,,, I agrre its the water when cleaning floors. this is why i love this place,,, corrects my misunderstandings!


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