Hi guys,

I've ripped out the old bath and had another nasty surprise. It seems
some clot may have used Multifinish instead of one-coat or Bonding at
a depth of about 3/4" straight onto brickwork. I'm guessing this is
what's happened, because this plaster has a definite pink tint to it.
I need to increase the depth of this plaster to around one inch, but
am reluctant to go over the existing plaster as I fear it will be a
very poor 'foundation' as it were. How can I tell for sure if the
builder/bodger misused a finish plaster on this brickwork? Is there a
simple way to tell?

cheers,

cd

On Wednesday, June 18, 2014 12:16:32 AM UTC+1, Cursitor Doom wrote:
Hi guys,



I've ripped out the old bath and had another nasty surprise. It seems

some clot may have used Multifinish instead of one-coat or Bonding at

a depth of about 3/4" straight onto brickwork. I'm guessing this is

what's happened, because this plaster has a definite pink tint to it.

I need to increase the depth of this plaster to around one inch, but

am reluctant to go over the existing plaster as I fear it will be a

very poor 'foundation' as it were. How can I tell for sure if the

builder/bodger misused a finish plaster on this brickwork? Is there a

simple way to tell?



cheers,



cd


Bonding / browning can be grey or pink (take a look at the descriptions here):

http://www.wickes.co.uk/Thistle-Bond...-25kg/p/220055
http://www.wickes.co.uk/Thistle-Brow...-25kg/p/190542

If someone has used multi finish but it's solidly attached, I wouldn't worry - just PVA it and carry on as normal.

"Cursitor Doom" wrote in message
...
Hi guys,

I've ripped out the old bath and had another nasty surprise. It seems
some clot may have used Multifinish instead of one-coat or Bonding at
a depth of about 3/4" straight onto brickwork. I'm guessing this is
what's happened, because this plaster has a definite pink tint to it.
I need to increase the depth of this plaster to around one inch, but
am reluctant to go over the existing plaster as I fear it will be a
very poor 'foundation' as it were. How can I tell for sure if the
builder/bodger misused a finish plaster on this brickwork? Is there a
simple way to tell?

cheers,

The colour of plaster (all grades) depends on the source of the gypsum it
was made with.

If finishing plaster is used too thickly, giant cracks appear on the
surface, if there are no cracks then this hasn't happened.
As long as it doesn't sound hllow when tapped, it will be OK.

The norm is to level a rough wall with sand/cement mix and to finish it with
plaster.
There was/is a plaster for rough filling in called "browning", doesn't seem
popular these days due to expense I imagine.
It was much lighter to handle than sand & cement mix. I think it has
vermiculite in it.

In article ,
Cursitor Doom writes:
Hi guys,

I've ripped out the old bath and had another nasty surprise. It seems
some clot may have used Multifinish instead of one-coat or Bonding at
a depth of about 3/4" straight onto brickwork. I'm guessing this is
what's happened, because this plaster has a definite pink tint to it.
I need to increase the depth of this plaster to around one inch, but
am reluctant to go over the existing plaster as I fear it will be a
very poor 'foundation' as it were. How can I tell for sure if the
builder/bodger misused a finish plaster on this brickwork? Is there a
simple way to tell?

Plaster is made from gypsum. Pure gypsum is white, but is not
normally used for making building plaster.
Normally gray or pink is used in the UK, depending which quary
it came from (and it's the same for bonding, browning, and
finish coat).

Finish coat shrinks considerably as it sets - if it's been used
more than a few mm thick, it will be riddled with deep cracks
which formed as it set (although that could then have been
properly skimmed over).

The important thing when plastering over is to be sure the
existing base it sound, and will remain sound with the extra
weight, and temporary dampness whilst the new plaster dries.
You will need to PVA the existing surface as is normal for
any reskim.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Many thanks, gentlemen. I think that covers it.
It's perfectly smooth so that looks promising. I'll test if first for
proper adhesion and PVA it as suggested, cheers.

On 18/06/2014 00:16, Cursitor Doom wrote:
Hi guys,

I've ripped out the old bath and had another nasty surprise. It seems
some clot may have used Multifinish instead of one-coat or Bonding at
a depth of about 3/4" straight onto brickwork. I'm guessing this is
what's happened, because this plaster has a definite pink tint to it.
I need to increase the depth of this plaster to around one inch, but
am reluctant to go over the existing plaster as I fear it will be a
very poor 'foundation' as it were. How can I tell for sure if the
builder/bodger misused a finish plaster on this brickwork? Is there a
simple way to tell?

cheers,

cd



awful lot of make up with plaster.
normally rough that out with 4:1 scratch coat first.



--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/