Repairing plaster

[chrissyv73]

I have had a damp issue coming through the wall which has been repaired out side and is now dry inside, can anyone tell a diy novice what I need to do and buy to repair this?

thanks,

chris

 

[Stanley services]

Hi. buy a very cheap damp meter. Stick it in to the wall. If the reading shows 20% or less the wall is safe to work with. Then buy a litre of shellac based stain block, zinsser bin red is the best. Open the pot, stir thoroughly and use a 4 inch medium pile mini roller with its own tray to roll the stain block on the entire affected part of the wall. As the stains are extensive, two coats would be best. Leave one hour between coats.
once complete, the application of the stain block will highlight all of the imperfections to be filled. Do not use ready mix, it’s too hard to rub down. Use a pre mix such as toupret interior filler. Flush fill the imperfections, wait to go off, then second fill the deeper imperfections as you can never fully fill them first time. Finally rub the filler down with 120 grade sandpaper. also caulk the cracks around the edges. Job done

 

[chrissyv73]

Would I need to replaster after? And thanks

 

[Stanley services]

The substrate appears to be late Victorian or Edwardian lime plaster. Provided none of the existing plaster is blown, you should have no reason to plaster if the instructions above are followed. Even if smaller areas are blown, you can hack these off and fill with the method above. If large areas are blown, I’m afraid you will need to plaster the entire wall.

 

[Stanley services]

Once you have satisfactorily repaired the walls, if you require a perfect finish. When you have applied the first coat of emulsion this first coat will highlight any areas you’ve missed with the filling process. All you need to do then is fine fill these imperfection, rub down the filler and apply two further coats of emulsion. Please ensure you use flexible filling knives. The best ones are from toolstation, click and collect, and they’re called euro filling knives. Give me a shout or further pictures of your work if you require any more advice.

 

[chrissyv73]

Large areas blown, so will plaster over after then? Cheers

 

[Stanley services]

Unfortunately that appears to be your only choice. If you are getting a plasterer in, reduce their costs by hacking off the blown areas and then pva the substrate so they don’t have to. Add 20% water to the pva. If the resulting holes are too deep, they will have to skim first with undercoat plaster, ( bonding) before putting finishing plaster on. Bear in mind that due to this plandemic the factories making the finishing plaster are closed. You’ll be very lucky to find a plasterer with some.

 

[chrissyv73]

Large areas blown, so will plaster over after then? Cheers

 

[chrissyv73]

Thanks again

 

[chrissyv73]

Thanks again for that