Hi


I need to do some interior rendering, but am unsure what mix to use.
Been using 1:1:6 for repointing outside, but this is very soft. The
wall is Victorian soft brick, hence the concern about simply applying
Dr Evil strength render. Should I render with strong stuff, or with
something soft that will crack instead of the bricks cracking when it
moves?


Regards, NT

"N. Thornton" wrote in message
om

I need to do some interior rendering, but am unsure what mix to use.
Been using 1:1:6 for repointing outside, but this is very soft.

Put a stronger mix in then. It will be OK at 4 to 1. Actually 6 to 1
is plenty. It's the lime that takes time to harden. The finish plaster
will take care of that.



--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

"N. Thornton" wrote:
I need to do some interior rendering, but am unsure what mix to
use. Been using 1:1:6 for repointing outside, but this is very
soft. The wall is Victorian soft brick, hence the concern about
simply applying Dr Evil strength render. Should I render with
strong stuff, or with something soft that will crack instead of
the bricks cracking when it moves?

Use 1:1:6 with a waterproofer (so that you can skim with gypsum
plaster). That will be considerably stronger than the lime
mix originally used! Use sharp sand, not "builders sand".


J.B.

On Fri, 2 Jul 2004 10:19:02 -0700 (PDT), Jerry Built
] wrote:

"N. Thornton" wrote:
I need to do some interior rendering, but am unsure what mix to
use. Been using 1:1:6 for repointing outside, but this is very
soft. The wall is Victorian soft brick, hence the concern about
simply applying Dr Evil strength render. Should I render with
strong stuff, or with something soft that will crack instead of
the bricks cracking when it moves?

Use 1:1:6 with a waterproofer (so that you can skim with gypsum
plaster).

Does that mean you shouldn't skim with gypsum plaster if you don't use
waterproofer, and if not why? I ask because I just did that.

That will be considerably stronger than the lime
mix originally used! Use sharp sand, not "builders sand".

Why not use "builders sand"? I ask because I just did that.

Phil
The uk.d-i-y FAQ is at http://www.diyfaq.org.uk/
Remove NOSPAM from address to email me

In article ,
Phil Addison writes:
On Fri, 2 Jul 2004 10:19:02 -0700 (PDT), Jerry Built
] wrote:

"N. Thornton" wrote:
I need to do some interior rendering, but am unsure what mix to
use. Been using 1:1:6 for repointing outside, but this is very
soft. The wall is Victorian soft brick, hence the concern about
simply applying Dr Evil strength render. Should I render with
strong stuff, or with something soft that will crack instead of
the bricks cracking when it moves?

Use 1:1:6 with a waterproofer (so that you can skim with gypsum
plaster).

Does that mean you shouldn't skim with gypsum plaster if you don't use
waterproofer, and if not why? I ask because I just did that.

Waterproofer will protect the plaster if the wall behind remains
damp. I haven't tried, but I suspect sand and cement without
waterproofer is still better than scratch coat plaster at resisting
water and it shouldn't deteriorate itself in any case (which scratch
coat plaster certainly will). However, if you are using sand and
cement as a waterproof scratch coat because of damp walls, you should
really add waterproofer.

That will be considerably stronger than the lime
mix originally used!

Which is not necessarily a good thing.

Use sharp sand, not "builders sand".

Why not use "builders sand"? I ask because I just did that.

I don't think it makes much difference. Sharp sand might make for
a stronger coat, but that's not necessarily good for this purpose.
If you wanted to polish the sand and cement as your facing surface,
then sharp sand wouldn't give as good a finish.

--
Andrew Gabriel

(Andrew Gabriel) wrote in message ...
In article ,
Phil Addison writes:
On Fri, 2 Jul 2004 10:19:02 -0700 (PDT), Jerry Built
] wrote:

Use 1:1:6 with a waterproofer (so that you can skim with gypsum
plaster).

Does that mean you shouldn't skim with gypsum plaster if you don't use
waterproofer, and if not why? I ask because I just did that.

Waterproofer will protect the plaster if the wall behind remains
damp. I haven't tried, but I suspect sand and cement without
waterproofer is still better than scratch coat plaster at resisting
water and it shouldn't deteriorate itself in any case (which scratch
coat plaster certainly will). However, if you are using sand and
cement as a waterproof scratch coat because of damp walls, you should
really add waterproofer.

Are there any instances where you should specifically *not* add
waterproofer to a mortar or render mix? Obviously there are
applications where it might be somewhat pointless, but can it ever do
any harm (other than waste the cost of buying it?)

David