How to patch & paint external rendered wall?

[MonikaJ]

 I would like to patch / repair external rendered wall which has some cracks / areas of render chipped off in couple of spots and then paint it. The wall is exposed to rain and not covered. 

Would you please advise product to patch the wall/ chips  and then products to paint (do we need primer, specific outdoor paint etc )?

thank you !

[Jewelleryrescue]

Hi @MonikaJ 

First  use a  wire  brush to free up  any more  loose chips you dont need to heavily brush it just the loose stuff.

I use a  product   called   bondcrete at  bunnings  as it is a cement based product  that has  extremly good adhesion to other cement products.

I would  paint your  wall with it  diluted  4 parts water to  1 bondcrete this will help bind the wall from further crumbling.

Next use the  same ratio of  4 parts  water to 1 part bond crete and mix in  general purpose cement in a  square bucket (easier to get a  trowel into)so it is a little harder than tooth paste and brush it with a  straw renders brush on the wall in the hollows (missing cement  zone and build up the wall to  flat.  A Steel  float can also be used and basically plaster the cement onto the wall will give a  better flat surface.  Some  stretch cracks  will appear but a  second  coating 24 hours later  will fill those.

The  aim is to  use  this  cement to resurface the wall same as  applying  a render and build up any low spots.  

Any good out door acrylic  paint will go onto easily.  The resulting  repair will be 10x  stronger than renders .

[EricL]

Hello @MonikaJ 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about how to patch your external wall.

It's great that you've received excellent advice from @Jewelleryrescue. Just to add to the suggestions made, I also recommend using Dingo 10kg Fast Set Hi-Strength Concrete for patching and quick repairs. Please make sure to mix only the amount you need and to place the rest in a zip lock bag so that moisture will not get at it. 

In regards to painting your wall any of the Dulux or Taubman outdoor paint product will work on your rendered wall. But before you paint your wall, is there any source of water coming through the back of the wall? If there is, it will need to be addressed as any paint placed on the surface of the wall will get pushed by the water coming through from the back.   

The soil from the back must be dug out and a water proofing paint must be applied and then the soil put back into place. This will stop the water from coming through. 

If you need further assistance, please let us know.

Eric

[MonikaJ]

Thanks Eric

It’s a good point about the moisture on the wall. It’s not a retaining wall but there is a pool right behind the wall. I’m guessing the water is rising up somehow. Is there a way to treat it from my side rather than from the neighbour side ?

[JacobZ]

Hi @MonikaJ,

It's hard to say the cause of the rising damp without seeing all sides of the wall. Unfortunately, it can be difficult to prevent rising damp after things have been installed.

I note that the soil is in direct contact with the bottom of the wall on your side. If you can pull it back from the wall and put a barrier in, maybe something like this this Icon Plastics 75mm x 10m Jarrah Garden Edge will help.

If we can do some further investigation around the source of the water, there may be more we can do, but unfortunately, it's unlikely you'll be able to completely fix the issue from your side alone.

Let me know what you think.

Jacob