unibond on new plastered ceilings / walls

Surface prep. Cleaning, Sanding, etc.
Robert18
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unibond on new plastered ceilings / walls

Post by Robert18 » Thu Sep 25, 2014 3:34 pm

Has anyone else had trouble coating over unibond which has been applied into the corners of the walls and around the edge of the ceilings?
I have used 240 grit paper to prep the room, hoover out,and applied 3 coats of PBW matt emulsion onto the ceiling, 1 coat onto walls followed by 2 coats of colour, the unibond is still showing through. :001_unsure:

any advice welcome.
thankyou

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Colin
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Re: unibond on new plastered ceilings / walls

Post by Colin » Thu Sep 25, 2014 5:08 pm

Are we talking caulk here? And is it that you can still see the white caulk flashing through the emulsion (in which case, buy a more expensive paint), or is it the caulk cracking?

Robert18
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Re: unibond on new plastered ceilings / walls

Post by Robert18 » Sat Sep 27, 2014 7:20 pm

Hey Colin, no it isn't caulk showing through. The plasters have painted on a thin strip of unibond along the top of the wall and along the ceiling ( probably to help bond the plaster to the plaster beads underneath) but after sanding down throughly and cutting in, the emulsion always seams to dry clear. ( over the top of the unibond) I have cut in each room 5/6 times to make it look decent

Robert18
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Re: unibond on new plastered ceilings / walls

Post by Robert18 » Sat Sep 27, 2014 7:23 pm

we have used Johnstones trade matt PBW for mist coating each room ( 2 coats) then Farrow and Ball (3 coats) colour

eddythepainter
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Re: unibond on new plastered ceilings / walls

Post by eddythepainter » Sun Sep 28, 2014 7:14 pm

Are you letting the coats dry properly not just touch dry as subsequent coats can liven previous coats and you would struggle to get coverage. also a new brush would help nursing it on. today's voc2010 paints does not have the coverage of the old stuff. makes our job that little bit harder.

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Colin
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Re: unibond on new plastered ceilings / walls

Post by Colin » Sun Sep 28, 2014 7:56 pm

Can't think why they would paint Unibond on the edges AFTER they've plastered. I should think the paint is just sliding off the sealed surface. You may have to prime the edges with a high covering primer like Bulls-Eye 1-2-3 first and then carry on. Tell the plasterers to stop messing about!

Robert18
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Re: unibond on new plastered ceilings / walls

Post by Robert18 » Sun Sep 28, 2014 8:43 pm

Yes we are letting the paint dry properly and using new purdy monarch elite brushes.
I will have a word with them tomorrow, never seen this done before

Thanks for all your help Eddy and Colin

Robert18
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Re: unibond on new plastered ceilings / walls

Post by Robert18 » Tue Sep 30, 2014 8:11 pm

i have been told I need to apply a coat of pva after plastering is this so and when do I need to do it.
Ygillchiv 16th Sep, 2011 Plastering
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You dont need to apply pva after the walls have been plastered.
Normally you use pva, prior to plastering 24hr before, then 2nd coat just before plastering and wait to go tacky.
When plaster has fully dried, you give it a mist coat of emulsion prior to your finish coats of paint.

B J D BUILDING/ROOFING 16th Sep, 2011


I have just found this question and answer on My builder.com for future reference so thought I would share it.
:good.gif:

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Colin
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Re: unibond on new plastered ceilings / walls

Post by Colin » Tue Sep 30, 2014 8:22 pm

PVA and painting should not ever go together

Louise
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Re: unibond on new plastered ceilings / walls

Post by Louise » Sat Jun 29, 2019 1:02 am

Yes I have had bad problems due to unibond being used as a sealer for new plaster and years ago the coving fitter painted about 20 cm on wall and ceiling to fit a 12cm coving. I painted the ceiling nine times, it ruined the finish, and you could still see brownish patches through the paint. Same in the conservatory, did the walls with a plaster sealer and four coats of crown didn't cover it. The paint is literally rejected. You can see it split into globules on the surface of the unibond. Next week I'm having a newly built room coved and if he uses unibond I'm going to throttle him with my bare hands! How do you cover over unibond? We can't be the only two people this happens to?

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