Repairing powdery gash in external render
 

A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think if I
just repair it as it using a bit of mortar, it will simply fall out again.

If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

Thanks
David

Repairing powdery gash in external render
 

Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think if I
just repair it as it using a bit of mortar, it will simply fall out
again.
If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

You can get waterproof PVA. AFAIK it only becomes waterproof when mixed
with cement as a slurry, but it might do the job.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

Repairing powdery gash in external render
 

The Medway Handyman wrote:
Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think if I
just repair it as it using a bit of mortar, it will simply fall out
again.
If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

You can get waterproof PVA. AFAIK it only becomes waterproof when mixed
with cement as a slurry, but it might do the job.



All pva does is prevents the brickwork absorbing water from the mortar
before it's had a chance to set. Works indoors or out and really has
nothing to do with how waterproof it is in the long term.

Repairing powdery gash in external render
 

Stuart Noble wrote:
The Medway Handyman wrote:
Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think if I
just repair it as it using a bit of mortar, it will simply fall out
again.
If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

You can get waterproof PVA. AFAIK it only becomes waterproof when
mixed with cement as a slurry, but it might do the job.



All pva does is prevents the brickwork absorbing water from the mortar
before it's had a chance to set. Works indoors or out and really has
nothing to do with how waterproof it is in the long term.

Thanks both.

So does that mean "waterproof" PVA is snake-oil and I can just as well
use the ornnery stuff I already have in!?

David

Repairing powdery gash in external render
 

Lobster wrote:
Stuart Noble wrote:
The Medway Handyman wrote:
Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think if I
just repair it as it using a bit of mortar, it will simply fall out
again.
If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

You can get waterproof PVA. AFAIK it only becomes waterproof when
mixed with cement as a slurry, but it might do the job.



All pva does is prevents the brickwork absorbing water from the mortar
before it's had a chance to set. Works indoors or out and really has
nothing to do with how waterproof it is in the long term.

Thanks both.

So does that mean "waterproof" PVA is snake-oil and I can just as well
use the ornnery stuff I already have in!?

David

IIRC exterior pva is called something else (eva?) and is more water
resistant but, as a sealer for masonry, it doesn't matter. It's only a
temporary barrier to allow the cement time to cure. Mortar sticks to a
shovel so well because the water doesn't get absorbed by the substrate.

Repairing powdery gash in external render
 

Lobster wrote:
Stuart Noble wrote:
The Medway Handyman wrote:
Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think
if I just repair it as it using a bit of mortar, it will simply
fall out again.
If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

You can get waterproof PVA. AFAIK it only becomes waterproof when
mixed with cement as a slurry, but it might do the job.



All pva does is prevents the brickwork absorbing water from the
mortar before it's had a chance to set. Works indoors or out and
really has nothing to do with how waterproof it is in the long term.

Thanks both.

So does that mean "waterproof" PVA is snake-oil and I can just as well
use the ornnery stuff I already have in!?

There are deffo two different grades, the waterproof one being twice the
price of the standard.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

Repairing powdery gash in external render
 

The Medway Handyman wrote:
Lobster wrote:
Stuart Noble wrote:
The Medway Handyman wrote:
Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. The hole is rather flaky and very powdery, so I think
if I just repair it as it using a bit of mortar, it will simply
fall out again.
If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?
You can get waterproof PVA. AFAIK it only becomes waterproof when
mixed with cement as a slurry, but it might do the job.


All pva does is prevents the brickwork absorbing water from the
mortar before it's had a chance to set. Works indoors or out and
really has nothing to do with how waterproof it is in the long term.
Thanks both.

So does that mean "waterproof" PVA is snake-oil and I can just as well
use the ornnery stuff I already have in!?

There are deffo two different grades, the waterproof one being twice the
price of the standard.


You buy at wrong place.

General purpose - £3-00
Water resistant - £3-12

Both per Kg inc. vat. Seems to be decent qaulity - least I have never
had a problem with it, conforms to all sorts of BS and Euro standards.

http://www.isaaclord.co.uk/searchProducts.aspx?searchTerm=pva&searchType=All% 20Words

Or I do! Difference, though, is negligible.

As I was writing I realised that it actually says "water resistant" not
"waterproof". I guess it depends on quite how important your application
whether the difference might be significant.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

Repairing powdery gash in external render
 

On 12 Apr, 15:35, Lobster wrote:
A small lump of render has fallen out - think it's been knocked by
something. *The hole is rather flaky and very powdery, so I think if I
just repair it as it using a bit of mortar, it will simply fall out again.

If this was an internal repair I'd be sloshing on dilute PVA first,
however that's not suitable for outside is it?

What does the panel reccomend I do?

Thanks
David

Dear David
PVA can re-emulsify
SBR is a glue and does not
Firstly cut out the render such as to make the hole larger next to the
brick that in is on the face of the render (undercut it like a dental
filling)
next put on undiluted SBR (Sryrene butadiene?) onto the brick and
undercut and within 30 mins whilst it is still tacky
put on the render with SBR in the mix according to the instructions
use a spllatter dash method of applying as best you can and leave it
to set before applying further coats of render
no coat should be more than say 12 mm thick
do not allow to dry only to set before applying the next coat
Chris

Repairing powdery gash in external render