Plastering query

dorky dave

Hi There everybody.

Im in the process of a new build and i have the plasterers on site doing the external nap plaster finish, they seem to have bypassed the scuding of the walls and went straight to the scratch coat and have left the coat approximately 8-10mm thick is this ok to do this or should i ask the question what the hell are they at ? Im concerned at the moment as it has only dawned on me today, they still have the dormers to do before they apply the final layer..... any insight would be very helpful

Thanks

muffler

Moved the above post to a thread of its own.

sinnerboy

This is not good .

Cement rich scudding should be liberally applied - and then left for min 7 days to harden before the scratch coat

Then the scratch in turn must be left another 7 days to harden . 8-10mm thickness is ok

The final coat must be weaker ( less cement ) and thinner ( 6-8mm) than the scratch coat

If you have hired a professional to certify the works inform him/her

Otherwise buy a copy of the Homebond Manual and show them whats expected - on pain of no payment

Lightning McQue

Sinnerboy

I have 50 mm stuck on quoins and I am wondering can I make the scud coat as thick as I like?

Can the scratch coat be thicker than 10 mm and final coat 8 mm?

I want to minimise the exposes side of the quoins.

Lightning

mickdw

It worrying but Im seeing this being attempted more & more on sites. The plasterers seem to think that scud coat is a thing of the past. I have also seen some cases of where the entire plasterwork has just blown off the wall. There is a connection there Im sure.

sinnerboy

Lightning McQue wrote: »

Sinnerboy

I have 50 mm stuck on quoins and I am wondering can I make the scud coat as thick as I like?

Can the scratch coat be thicker than 10 mm and final coat 8 mm?

I want to minimise the exposes side of the quoins.

Lightning

I would not try to alter the traditional techniques to achieve greater render thickness . I would use expended metal lathing and mechanical fixings

However - its purely a matter of personal taste of course . I would not seek to minimize the quoins

http://images.google.ie/images?hl=en&source=hp&q=qoins&btnG=Search+Images&gbv=2&aq=f&oq=

dorky dave

Thanks Sinnerboy for the feed back, due to the house not been scuded will the plaster eventuallylose adhesion or with the abrasive nature of the blocks should it aid the adhesion process , also what worries more is that when the guys were plastering night temp were below minus, i have inspected the scratch coat and it would appear no visable cracks, also the scratch coat does not appear hollow, what is the recommened thickness of the overall plaster on the wall ??

Cheers

Lightning McQue

Guys

Just wondering about the type of sand to be used for a nap plaster finish.

The stonemason mentioned to me that the sand I purchased is too fine and that he wouldnt use it to plaster his house.

So the question is what type of sand should I be looking for? Should it be very course?

Thanks.

Lightning