Weber Pral M over S and C scratch coat

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Sturnbull

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Got a question hopefully somebody can answer or advise. I've read a few posts but cant find a definitive answer.

Can you use Weber pral M over a sand and cement scratch coat?

Ive used Weber a good few times but I don't claim to be an expert on it.

The jobs I have done in the past have been over new block work or rend-aid.

The reason I am looking to go over S and C and not rend-aid is that I need to EML the background first. I was hoping to use a 4:1 scratch coat, key, then apply the weber at 18mm and scrape back to 15mm.

So my main questions are, is there a Weber product that can be applied over EML, or is it fine to apply over s and c. I was also thinking about using Lime in the scratch to allow for any movement of the Weber pral M.

Any help or advice is appreciated!

Thanks
 
Jgreenplastering

Jgreenplastering

Private Member
The bottom line is Weber won't offer any guarantee over a S & C scratch.
You could use there OCR then just a 12-12mm scratch back to 10mm.
I know loads on here will use sand and cement to save costs and have no problems but personally I use a system by one manufacturer.
Are you Using EML for a specific reason? Is the substrate badly damaged?
If it's not to bad could use fibre mesh in the scratch?
If it needs a good scratch to build out you could use something like Parex Monogris E with mesh to build out around 10mm then top with Monorex.
Material costs will be offset on the labour saving of EML.
If you say what your going over I'm sure more will have other options.
If your total thickness exceeds 25mm it doesn't matter if you mix products because you'll not get a guarantee anyway.
 
S

Sturnbull

New Member
Jgreenplastering said:
The bottom line is Weber won't offer any guarantee over a S & C scratch.
You could use there OCR then just a 12-12mm scratch back to 10mm.
I know loads on here will use sand and cement to save costs and have no problems but personally I use a system by one manufacturer.
Are you Using EML for a specific reason? Is the substrate badly damaged?
If it's not to bad could use fibre mesh in the scratch?
If it needs a good scratch to build out you could use something like Parex Monogris E with mesh to build out around 10mm then top with Monorex.
Material costs will be offset on the labour saving of EML.
If you say what your going over I'm sure more will have other options.
If your total thickness exceeds 25mm it doesn't matter if you mix products because you'll not get a guarantee anyway.
Click to expand...
Thanks for advice mate! the reason i'm using EML is because it is a timber framed house, theres 2 panels on the 1st floor that have old cladding on, I need to remove the cladding and fix EML to the joists. So the EML is not for structural reasons. I understand the guarantee is void but from what I've read, Weber will always blame the applicator anyway regardless what the fault is. My main worry is cracking, and bond failure?
 
Jgreenplastering

Jgreenplastering

Private Member
Sturnbull said:
Thanks for advice mate! the reason i'm using EML is because it is a timber framed house, theres 2 panels on the 1st floor that have old cladding on, I need to remove the cladding and fix EML to the joists. So the EML is not for structural reasons. I understand the guarantee is void but from what I've read, Weber will always blame the applicator anyway regardless what the fault is. My main worry is cracking, and bond failure?
Click to expand...

If your fixing EML to the joist what's behind the EML?
I wouldn't use s and cement on timber frame.
You want thin coat stuff.
Speak to Parex or Weber they will spec for you can't go wrong then.
 
S

Sturnbull

New Member
Jgreenplastering said:
If your fixing EML to the joist what's behind the EML?
I wouldn't use s and cement on timber frame.
You want thin coat stuff.
Speak to Parex or Weber they will spec for you can't go wrong then.
Click to expand...
sorry i'm not fixing straight to joists, I was going to screw cement boards to the joists, then fix EML to that.

There may be a better system to use then what I'm thinking of doing. What system would you personally go with?
 
Jgreenplastering

Jgreenplastering

Private Member
I'd use a render carrier board then a thin coat system.
If you call Parex ask for your area rep and tell him the finish your looking for and they will tell you what to use mate.
I'd forget the EML and sand and cement if I were you.
To heavy and not flexible enough to withstand any movement.
 
FreeD

FreeD

Private Member
Exterior ply, breathable roofing felt, stainless eml. Scratch with sand/cement with waterpoofer 4-1, leave for a week, then top with Weber pral.
 
Arti

Arti

Well-Known Member
Just use a render board. You can still use pral, just use LAC as your base coat

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kgreigh

kgreigh

Well-Known Member
I'd use a thin coat,get the spec from a manufacturer of choice then you get the guarantee :)
 
keithuk

keithuk

Private Member
If you have been on there courses and they come and see your work , then they are ok ,have not needed to deal with them for years


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keithuk

keithuk

Private Member
Back in the day you had to say your company name which was then checked out to see if you had been trained on their materials


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