Hi, Thanks in advance if you can help. I have painted a few internal walls with black bitumen damp proof paint thinking it was as simple as doing a coat of that and then painting on top with emulsion. I know... how wrong I was. All the walls now look like a dried riverbed and have all cracked. I have been thinking about what to do because the reason I did this was to stop a previous damp problem that’s been fixed now since it kept coming through the new paint and plaster. To save having to skim again I was thinking how best to approach this now, can I simple just sand down the paint and do a mist coat and carry on as normal, do I need to do a layer of undercoat first? Do I need to get some pva glue? Do I really need to skim? Please help if you can!! Many thanks all!
Bedec Barn paint covers bitumen, not sure how long the bitumen has to be on for to fully dry first though. https://bedec.co.uk/bedec_products/barn-paint/
Thanks although, only issue that this is really for outdoor use, this is for internal walls and I want to use normal emulsion
Oh dear, you have now a huge problem................. damp is best treated at source, there is a way around this, can you post any photos as that would provide a far better idea of how to deal with the task ahead.
Thank you for your help. It won’t let me post pictures- apparently too large for the server to process. The source of the damp has been treated however it left the walls in a horrendous state hence the paint. The stage where I am at now the walls look like this - but in white and I’m not really liking the texture - https://goo.gl/images/4qdCZ3
Messy and time consuming job but I am wondering if a wallpaper steam stripper might fetch the white paint and the bitumen off right back to the plaster, a hot air gun also may be worth a try. A product called Three in One Foil is a very good covering for damp walls, it has to be stuck to the wall like wallpaper with a special adhesive that sticks to damp. Once it has dried the foil is then cross lined with lining paper horizontally and once more vertically then decorated to you're chosen finish......long winded I know but it does the job!
My view would be to remove the mistake as simply and best as possible, others on here may be able to offer other options. KIAB is the chap on here to advise you on how to load on pictures so he may be around soon to help.
Thank you, I’ll hold on in hope of a hopefully easier solution and if not yours might be it. You can’t actually see the cracks from a distance just when up close but it’s not the best texture for a house. In the mean time ive uploaded a picture on twitter... here you go https://twitter.com/thejosephdixon/status/1082768608873324544?s=21
Try 'Tiny Pic' http://tinypic.com/ Bitumen damp proof paint on internal walls. No chance in hell painting them with emulsion, best option is off with the lot & replaster, or overboard wall(s) with plasterboard & skim. Here we go.
When you say sleeping through do you mean cracking again? And how long? A decorator has given me a quote to fix by using two thinned undercoat layers and then back to emulsion but I’ve read else where online it might not work.
No, the oil/tar in the bitumen will leach out,as to how long, I don't know. Can't see two thinned undercoat layers and then back to emulsion working.
Even if that would work (which it won’t), hows that gonna solve the cracking issue ? What was the actual ‘thinned undercoat’ to be used I wonder ? Thinned out emuslion perhaps ? You sure this geezer is a decorator and what kind of assurance has he given you that his idea will work Even if it did work (which it won’t), likely to be temporary until the bitumen bleeds through the water based undercoat / emuslion in time Nightmare situation I’m wondering if a Zinnser primer (not sure which one) maybe 2 coats then papering with Wallrock Fibre Liner would work - Your thoughts please Astra
Don't you put a wet coat of bitumen paint on, then blind it with silver sand and then plaster over? That would be easier than trying to strip the bitumen off.
Use to many moons ago,I haven't don't that in years. And use sharp sand to blind & then render in old days.