Render failure

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Olican

Olican

Private Member
Rendered a timber frame block of flats 5 years ago and one elevation has delaminated from the boards and shelled off.

All the work was carried out to spec, rest of the job is sound.
I'm in the clear on this one , the contractor is not looking to me for responsibility I'm just curious as to what could of caused it. Site meeting on Wednesday with Knauf, the render board supplier and a few other suits. I'll be keeping my mouth shut. Looks like it'll be an insurance claim.

Base coat up210 hand applied, fully meshed onto top 1/3rd of base coat. Materials mixed with clean tap sourced water. Sufficient curing time before toping with Knauf mamorit

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I always think that the other side of the aqua panel gives the better key. the only reason Knauf advises the smooth side is on the outside is that the advertising is on this side.
i hope that the aqua panel has NOT had a coat of sbr ?
 
malc said:
I always think that the other side of the aqua panel gives the better key. the only reason Knauf advises the smooth side is on the outside is that the advertising is on this side.
i hope that the aqua panel has NOT had a coat of sbr ?
Click to expand...
No SBR malc
 
Dansouthcoast84 said:
i heard of one a short while ago
a large builder tried taking a installer to court over a failure. turned out the wrong boards were used and the builder supplied them
Click to expand...
Looks like moisture got in at the corner bead or is it my phone
 
malc said:
I always think that the other side of the aqua panel gives the better key. the only reason Knauf advises the smooth side is on the outside is that the advertising is on this side.
i hope that the aqua panel has NOT had a coat of sbr ?
Click to expand...
you would always think the premeshed /keyed side is for rendering wouldnt you. common sense i would of said. dont understand why they say smooth side. must admit
 
malc said:
I always think that the other side of the aqua panel gives the better key. the only reason Knauf advises the smooth side is on the outside is that the advertising is on this side.
i hope that the aqua panel has NOT had a coat of sbr ?
Click to expand...
They could just as easily advertise on the better side, that does not make sense.
 
I would be looking at that large trim/band above to see if water getting behind or capillary attraction in same area allowing water to get behind render.
 
Biggest problem with modern render boards is their waterproof nature works against it .
unlike masonry which can absorb water the panels cause water to get trapped between panel and render and the frost /thaw cycle is able to delaminate render from board.
The use of full mesh does not help as it means a local failure will pull the lot off.
A render board with small holes (seriously) across whole surface to act as a key and also allow water to settle and dry out naturaly may help.
 
Hi guys

It is not Knauf policy to comment on an open forum..... please do not push on this...

I’ve been off for a few days, but know nothing at all about this project, so I assume it is not a Knauf Aquapanel Outdoor application.... but, I may find out later in the week

It is a lovely looking project though....
 
malc said:
I always think that the other side of the aqua panel gives the better key. the only reason Knauf advises the smooth side is on the outside is that the advertising is on this side.
i hope that the aqua panel has NOT had a coat of sbr ?
Click to expand...

Hi Malc (all)

Knauf Aquapanel Outdoor recommends the smooth side out for rendering, as the rough side has the batch number on it.... in reality, it does not matter which side you render to

Most of the render system suppliers (and the BBA) have tested both sides and get identical delamination performance on both faces (this is the pull off test, not a failure )
 
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tapit said:
Biggest problem with modern render boards is their waterproof nature works against it .
unlike masonry which can absorb water the panels cause water to get trapped between panel and render and the frost /thaw cycle is able to delaminate render from board.
The use of full mesh does not help as it means a local failure will pull the lot off.
A render board with small holes (seriously) across whole surface to act as a key and also allow water to settle and dry out naturaly may help.
Click to expand...

Hi bud

Knauf Aquapanel Outdoor is not waterproof, but water resistant. Water can enter and exit the Knauf Aquapanel in a similar way to blockwork, and yet it remains stable and should not have moderne render products delaminate

Knauf Aquapanel Outdoor is a board designed specifically as a directly applied render carrier board, where other boards have other primary purposes and get used for this application as well....

Feel free to get in touch with me for more info, if needed

Richard Lord
Knauf
 
Runswithscissors said:
Hi guys

It is not Knauf policy to comment on an open forum..... please do not push on this...

I’ve been off for a few days, but know nothing at all about this project, so I assume it is not a Knauf Aquapanel Outdoor application.... but, I may find out later in the week

It is a lovely looking project though....
Click to expand...
slopy shoulders there mr Lord! :risas: :risas: :risas: :risas: :risas: :risas: :risas: :risas: :risas: :risas:

no comment he says.

from the pictures they look 8x4 sheets, doesnt look like.your boards mate.

how are you anyway
 
Dansouthcoast84 said:
slopy shoulders there mr Lord! :risas: :risas: :risas: :risas: :risas: :risas: :risas: :risas: :risas: :risas:

no comment he says.

from the pictures they look 8x4 sheets, doesnt look like.your boards mate.

how are you anyway
Click to expand...

Phew.... glad you thought that too....

Company policy marra - sorry

I’ll Bell ya next week.. with the weather changing, must be breakfast time!
 
Probably not relevant but that looks like green mold on the columns and some soffits, so is this the north-east side that never gets any heat on it or chance to dry out?
 
Olican said:
Rendered a timber frame block of flats 5 years ago and one elevation has delaminated from the boards and shelled off.

All the work was carried out to spec, rest of the job is sound.
I'm in the clear on this one , the contractor is not looking to me for responsibility I'm just curious as to what could of caused it. Site meeting on Wednesday with Knauf, the render board supplier and a few other suits. I'll be keeping my mouth shut. Looks like it'll be an insurance claim.

Base coat up210 hand applied, fully meshed onto top 1/3rd of base coat. Materials mixed with clean tap sourced water. Sufficient curing time before toping with Knauf mamorit

View attachment 41333
View attachment 41334
Click to expand...

Looks like plasterboard mate, you sure you didn't fix the wrong boards :LOL:
 
Olican said:
Yes mate was 9.5mm plasterboard, was told that would be fine as long as I pva'd them first :hueco:
Click to expand...
Your a true pro
I'd tell the architect to get a bead of silicone under those horizontal features to ensure they drip clear of below render sections or other walls may go the same way
 
bof said:
Your a true pro
I'd tell the architect to get a bead of silicone under those horizontal features to ensure they drip clear of below render sections or other walls may go the same way
Click to expand...
im sure those horizontal features will be compression joints
 
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