Skim or Replaster?

JRG123

Renovating spare bedroom in our victorian terraced house. 

Taken the lining paper off and skirting/architrave.

This wall separating front main bedroom and spare bedroom seems to be lime plaster and skimmed at top in gypsum for some reason.

There's a fair old chunk missing at base.

Should this be stripped back to brick and replastered or just skimmed over ?

Don't mind a bit of hard work and dust removing plaster myself if results are worth the effort!

 

secla

We have been working through out lime plastered 1930s house and have done a bit of a mix of both
im guessing the bottom is missing due to there being skirting there at some point, you can see the wooden blocks between bricks that the skirting would have been nailed to.
Some of out walls were starting to come loose in places especially where architraves etc had been removed and they went from bad to worse and ended up stripping and boarding, we have also had some ceilings down which is a horrible dusty job. but if plaster is solid they can be skimmed over

stuart45

What are you doing with the other walls in the room?

WIAWSNB

When you tap the wall, are there any places where it sounds remotely hollow?
Are there any cracks? If so, when you run your fingers across them, can you feel a 'step', the slightest difference in heights?
If in any doubt...
Is this upstairs or down? If the former, I'm guessing normal bonding and skim could be used to replace what's there? (But Stuart can confirm).
I'm guessing the top strip of modern plaster is due to the picture rail having been removed, and resulting different levels of wall surface. 
Obviously a very messy job, but rewarding. My first reno was a 3 storey Vic town house, where the old stuff came off with a shovel. Make sure your mask and goggles are good quality...

Grenage

Skim if the base is sound, replaster if it isn't.  A little bit of blown plaster isn't generally a problem, a very large area can be.

Grinch6912

Firstly, are you skimming/repairing it yourself? If not, ask your plasterer.  If you ignore their advice at any stage they will not guarantee the job. For example, they suggest taking back to brick, you ask them to just repair n skim, job fails, they won’t rectify for free, you’re a few hundred £ in the hole.

If you’re doing all the work….check the (old stuff particularly) existing plaster is bonded. No hollow sounds when you knock. Repair skirting void by either bonding plasterboard to it or level off to existing plaster with hardwall/bonding. Scrim tape any cracks/joins. Prime with neat sbr. I’ve skimmed a lot of walls like this, and sbr is the only product that kills the suction. You can then skim when dry. There’ll be lots of folk who argue about pva v sbr etc. My advice is based upon my experience. I’ve pva’d and gritted walls like this and suction was still horrendous 

Best job on your wall would be stripping back to bare brick, dot n dab new board on, scrim, skim. Make sure new boards are a cm off the floor, to avoid pulling up moisture, level and have a solid line of adhesive across the wall at top, as required by building regs. Loads of decent YouTube vids on dot dab.
Also, some old lime plaster contains arsenic, so wear a suitable mask

Enjoy 

JRG123

Thanks everyone — I will do some more investigating when back home later.

@stuart45

These are the other walls, in a bit better condition so was thinking they might just need a skim?

It's the upstairs rear/second bedroom.

The original picture I shared is the wall between main upstairs bedroom and second bedroom.

The wall where door is has more modern plasterboard where there was lathe and plaster before.

FreeBear

Grinch6912 said: Best job on your wall would be stripping back to bare brick, dot n dab new board on, scrim, skim. Make sure new boards are a cm off the floor, to avoid pulling up moisture, level and have a solid line of adhesive across the wall at top, as required by building regs. Loads of decent YouTube vids on dot dab.

If you strip more than 25% of an exterior wall back to brick, Building Regulations require you to insulate the wall (subject to cost/payback considerations). With a solid brick wall typical of the Victorian era, using modern materials & methods is best avoided. Usual recommendation is woodfibre or cork insulation finished off with a lime plaster.

Contrary to popular belief, I'm of the opinion that gypsum plasters are breathable and would work over woodfibre/cork.

Not a fan of dot'n'dab as damp will come through the wall & dabs of adhesive and show up as dark spots on the walls. Alternatively, the dabs of adhesive will give rise to slightly colder spots on the wall and attract condensation (again, showing up as dark spots).

Grinch6912

FreeBear said:

Grinch6912 said: Best job on your wall would be stripping back to bare brick, dot n dab new board on, scrim, skim. Make sure new boards are a cm off the floor, to avoid pulling up moisture, level and have a solid line of adhesive across the wall at top, as required by building regs. Loads of decent YouTube vids on dot dab.

If you strip more than 25% of an exterior wall back to brick, Building Regulations require you to insulate the wall (subject to cost/payback considerations). With a solid brick wall typical of the Victorian era, using modern materials & methods is best avoided. Usual recommendation is woodfibre or cork insulation finished off with a lime plaster.

Contrary to popular belief, I'm of the opinion that gypsum plasters are breathable and would work over woodfibre/cork.

Not a fan of dot'n'dab as damp will come through the wall & dabs of adhesive and show up as dark spots on the walls. Alternatively, the dabs of adhesive will give rise to slightly colder spots on the wall and attract condensation (again, showing up as dark spots).

Op stated the wall in question separates two bedrooms, ergo it’s an interior wall. Dot and dab is absolutely suitable and there is no requirement to insulate. As for dealing with exterior wall, the usual method would be batten, kingspan and board. Yes, you can ponce about with cork and lime plaster if you want, but in my experience that’s an inferior option. 

JRG123

Thanks @Grinch6912 and @FreeBear

I will get a plasterer in, I don't trust myself with that! I would only be up for the grunt work/stripping back.

Great to have all this context, I think 3 of 4 walls can be skimmed.

With the offending wall it was the lime plaster that had me worried if I needed to find a specialist lime plasterer to replace like for like but sounds like gypsum is ok, particularly as its an interior wall. With the missing chunk, the hardwall/bonding option sounds like the way but I will seek advice of plasterer now I know it doesn't need to be specialist.

FFHillbilly

FreeBear said:

Not a fan of dot'n'dab as damp will come through the wall & dabs of adhesive and show up as dark spots on the walls. Alternatively, the dabs of adhesive will give rise to slightly colder spots on the wall and attract condensation (again, showing up as dark spots).

this is not a fault of dot n dab, it shows that water is getting into the wall somehow. The best solution is to stop the water getting into the wall from the outside, ie. rendering, gutters, windows etc..
If water is getting in from the outside my first thought would be to stop that, before trying to find some different interior plastering method designed to hide the fact that "water is getting in from the outside!"

and it's too hard to say from a picture alone if a wall can be primed and over skimmed or if it needs to be striped to brick, depends how old the plaster is and how well stuck to the brick it is. you need to assess it in person, or have a plasterer (whom you trust) assess it and make a descicion