Very Patchy Mist Coat - Causes?

Refurbiton

New Member
Hello everyone,

Have found the site quite useful as a DIYer and now I have a question I'd like to ask.

I recently had my victorian semi rendered and plastered after DPC injection (I know what a waste of time/money - separate discussion). The majority of the old lime plaster had blown and failed due to water ingress from failed gutters, failed cement flashing around chimney and the external ground being too high. All this has been rectified and with the dry summer we've had the place has dried out nicely.

The old plaster was taken off 1m high on all external walls and to ceiling height on the chimney breast and the right hand corner of the bay window. This was left exposed for 6+ weeks whilst other works were carried out.

I have mist coat the new plaster (when it was fully dried) and found it to be very patchy, so I went over again with undiluted contract matt and still these patches show through the paint. In some places I have applied a second coat of undiluted and it seems to be better but other patches haven't taken at all.

I believe it to be the plaster and not the paint because the ceilings are blemish free. They were over boarded and skimmed, mist coat and 2 coats of contract matt and they are fine.

Paint used is LEYLAND TRADE CONTRACT MATT EMULSION PAINT BRILLIANT WHITE

The plasterer said at the time they found it very difficult to skim where there was existing paint (mostly internal walls and the area above the hacked off plaster) as it kept sliding?

What would be causing this mottled affect? The surface is smooth and not rough. I will be using very dark colours so want to make sure these patches don't show through the finished colour

If it is the fault of the plasterer where do I stand on getting it corrected?

Please let me know if you need any other info.
 

Attachments

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  • Mist Coat Living Room.JPEG
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Is bonding the name of the issue or is that the type of plaster used? How can this be rectified to give a decent finish for painting?
 
Hello everyone,

Have found the site quite useful as a DIYer and now I have a question I'd like to ask.

I recently had my victorian semi rendered and plastered after DPC injection (I know what a waste of time/money - separate discussion). The majority of the old lime plaster had blown and failed due to water ingress from failed gutters, failed cement flashing around chimney and the external ground being too high. All this has been rectified and with the dry summer we've had the place has dried out nicely.

The old plaster was taken off 1m high on all external walls and to ceiling height on the chimney breast and the right hand corner of the bay window. This was left exposed for 6+ weeks whilst other works were carried out.

I have mist coat the new plaster (when it was fully dried) and found it to be very patchy, so I went over again with undiluted contract matt and still these patches show through the paint. In some places I have applied a second coat of undiluted and it seems to be better but other patches haven't taken at all.

I believe it to be the plaster and not the paint because the ceilings are blemish free. They were over boarded and skimmed, mist coat and 2 coats of contract matt and they are fine.

Paint used is LEYLAND TRADE CONTRACT MATT EMULSION PAINT BRILLIANT WHITE

The plasterer said at the time they found it very difficult to skim where there was existing paint (mostly internal walls and the area above the hacked off plaster) as it kept sliding?

What would be causing this mottled affect? The surface is smooth and not rough. I will be using very dark colours so want to make sure these patches don't show through the finished colour

If it is the fault of the plasterer where do I stand on getting it corrected?

Please let me know if you need any other info.
still a lot of damp in your house m8
 
Hello everyone,

Have found the site quite useful as a DIYer and now I have a question I'd like to ask.

I recently had my victorian semi rendered and plastered after DPC injection (I know what a waste of time/money - separate discussion). The majority of the old lime plaster had blown and failed due to water ingress from failed gutters, failed cement flashing around chimney and the external ground being too high. All this has been rectified and with the dry summer we've had the place has dried out nicely.

The old plaster was taken off 1m high on all external walls and to ceiling height on the chimney breast and the right hand corner of the bay window. This was left exposed for 6+ weeks whilst other works were carried out.

I have mist coat the new plaster (when it was fully dried) and found it to be very patchy, so I went over again with undiluted contract matt and still these patches show through the paint. In some places I have applied a second coat of undiluted and it seems to be better but other patches haven't taken at all.

I believe it to be the plaster and not the paint because the ceilings are blemish free. They were over boarded and skimmed, mist coat and 2 coats of contract matt and they are fine.

Paint used is LEYLAND TRADE CONTRACT MATT EMULSION PAINT BRILLIANT WHITE

The plasterer said at the time they found it very difficult to skim where there was existing paint (mostly internal walls and the area above the hacked off plaster) as it kept sliding?

What would be causing this mottled affect? The surface is smooth and not rough. I will be using very dark colours so want to make sure these patches don't show through the finished colour

If it is the fault of the plasterer where do I stand on getting it corrected?

Please let me know if you need any other info.
Try this
Screenshot_20210910-182541.png
 
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