Exterior plaster render

secman

Thinking of using white sand, white cement and lime for a chalk white smooth finish on exterior walls. have seen a job in progress, looks fine. However would like to hear from anyone out thwere who has used this method for rendering year + ago ............. how has it weathered, does it still look ok ?

rooferPete

Hi secman,

One of my business partners used a similar mix when building his house some 25 years ago, the main difference being he used pebble dashing which I thought would gather dirt.

He sold the house recently and it looks as good as it did way back then, we all thought he was a bit crazy because white cement was very expensive at the time (around £5.00 a man size bag 50 kg).

The combination of the white walls and truetone slates suited the design of the house, he was so happy with that finish he is using the same on his new home.

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mjffey

If you use this combination does that mean that you don't have to paint it anymore, never ever? Would be great.

rooferPete

Hi,

I think part of the reason for the success of the finish I described is there were no trees close to the house, if anything the dashing should have caused problems but didn't.

A large factor is the plasterer and even more important the labourer responsible for keeping the mix consistant.

The parts that were finished later were the piers at the front of the house they were plastered with a standard sand / cement mix and needed painting every year.

As you can guess he is a Gent who likes everything Black or White, no grey areas

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anon1

The white plaster may change colour slightly when wet.

Viking House

We have used 1 part cement, 2 parts lime and 5 parts sand.
The lime makes the plaster more flexible/breathable and more resistant to cracking.

Just a quick question...

What is the best type of sand to use? I am looking to do something similar on my house.

I will be plastering on to expanded polystyrene covered with expanded metal or plastic mesh to ensure adhesion.

foamcutter

Secman,
I believe white sand/cement rubbed up can be prone to pearl cracking (very fine lines). We opted for white sand/cement and a fine white marble dash. 15 years no discolouration and just the occassional power hose.

dolanbaker,
there are specialist renders that can be used with polystyrene here a few links

Facade systems from Dublin are agents for the weber range of renders
facades.ie

Qmax finishes from Rathcoole are agents for the Parex range of renders. www.parex.com qmaxfinishes

Greenspan from Limerick are agents for the Dryvit range of renders. www.dryvit.com greenspan.ie

Thanks foamcutter, will contact the companies directly.

dalto23401

I was trying to apply finish coat with lime plaster on internal walls using lime putty and some sand. It cracks all the time. Does anyone have any experience of using lime based finish plaster?

rooferPete

Hi,

That is a very "Olde Time" type of plastering but can be very good as it allows the walls to breathe naturally.

It is very important to make sure the base is very wet and keep wetting it as you progress.

As the weather is very warm you may have to keep the finished wall moist using damp cloths, painters dust sheets soaked have been used I saw old curtains used once they did the job.

It is a skill unlike using modern plaster finishes, I would suggest that you work on small areas first to get the "feel" of the product especially in hot weather, if there was more moisture in the air and the walls cooler I would expect it easier to apply and get a nice finish.

I hope the above is some help.

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