Painting exterior wall

[Supernatural323]

Hi all,

I need to paint my exterior wall. It's never been painted. 2 sides was rough casted last year, the other side 4 years ago.

Can anyone recommend me good paint?
Do I need to thin down 1st,2nd,3rd coat?
How many coats does it need?
Any further advise you can give?

Many thanks

John

 

[emilybronte]

Any good quality masonry paint will do. Sandtex, Leyland or Dulux Trade, for example. It goes further than you think. Check coverage on tin/website to avoid buying too much.

I would slightly water down the first coat (say 80:20), then apply another one or two coats full strength.

 

[Supernatural323]

Thanks fir the reply emily,

So you say add 20% water to the first coat. Sounds alot. Do they say that on the tin?

 

[emilybronte]

Thanks fir the reply emily,

So you say add 20% water to the first coat. Sounds alot. Do they say that on the tin?

No, I made it up.

 

[Chri5]

Most paint makers suggest diluting to a max of 5%

However, Emily is suggesting a mist / starter coat so 20% would be fine. With rough cast you do need the paint to be runny to get in to the crevices.

Laying on thick paint is harder and slower. I'd go with Emily's suggestion and depending on how runny the paint needs to be look at more coats against fewer thicker slower coats.

If the rough caste isn't that rough you might find a long haired masonry roller will help with the time factor.

 

[Supernatural323]

Hi Again,

Thanks for the advice.
I have painted first side of house as suggested, looks good.
People have been shocked that I did not use sealer/primer. Should I have? the wall was roughcast-ed 12 months ago.

I have side of house which was roughcast-ed 5 years ago? I am going to pressure wash it, do I need to prime it? not sure what priming does.

Many thanks in advance

John

 

[Supernatural323]

Anyone?

 

[misterhelpful]

The watered down mist coat is acting as the primer sealer. People will use other products to seal with but the best thing is to do as you have done and use a mist coat of masonry paint.

Pressure washing the other wall is fine but, if it has any algae/moss on it, you need to clean it with a fungicidal wash or bleach solution before rinsing off with the washer.

 

[Supernatural323]

Thanks misterhelpful
There no alge or moss. But parts of wall has turned red like you see on many houses. Not sure what causes this? Is it ok to paint over?

Also, just looked over the wall I have finished, there seems to be like hairline cracks in the paint. The paint was very thick even though I added a little water?
It does say on the tube that the last coat should not be diluted.

I have absolutely no experience in painting exterior walls.

Any tips would be very welcome

Regards

John

 

[Supernatural323]

Anyone??

 

[Supernatural323]

?

 

[misterhelpful]

Walls turning red could still be algae such as trentepohlia (spelling?) which is difficult to kill off with standard fungicidal washes. Hopefully its not that as if not killed, or just painted over, it will reappear.

As for the cracks in the dried paint, I'm pretty sure it's because you didn't spread the paint out enough and it has cracked as it dried out. This shouldn't be a major problem providing it hasn't split open to expose the substrate to rain and/or frost. You could apply another coat (or test a spot)to see if it fills the cracks, to be on the safe side.

 

[johnsnyder]

I think you should use kwal paint for the exterior wall, as it is long lasting, and it is also water proof and prevent your wall. It provide great washable finish and can be clean-up with water & soap. I have personally used this for my home exterior walls, you can try these out.

 

[Supernatural323]

Just started another thread. Can you guys have a look, u have been very helpful in this thread.

Thread is:
//www.diynot.com/forums/decorating/painting-external-wall-but-wall-has-turned-red.412465/

Many thanks