painting concrete rendered wall

[bbabythai]

We are renovating a building and have ripped off the old wood and other things off the walls. Now the concrete rendered walls are in bad shape. I have patched up a few of the bigger holes with concrete but theres more to be done. For the smaller holes what would I use to fill the gaps?   Should I sand with hand sanding or buy and electric sander? What % paper?

 

If everything is patched up are these walls going to look ok with a lick of paint? Would I be painting it with an undercoat first and then an interior semi gloss? Or what can you suggest

 

The first photo is where the old tiles were removed

 

thanks

Edited June 7, 2018 by bbabythai

[mogandave]

I would hire a a guy to slick-coat it with the wall-finishing cement they use.

Sanding is pointless, just painting will look like sh*t.

[bbabythai]

On 6/7/2018 at 10:27 PM, mogandave said:

I would hire a a guy to slick-coat it with the wall-finishing cement they use.

Sanding is pointless, just painting will look like sh*t.

do you know a brand of 'wall finishing cement' on sale in thailand. I need to show this to the painter (thai)

thanks

[VocalNeal]

With concrete th most important thing is the first coat which , surprise, is usually wrong here. 80% thinners, 20% pigment.

 

The thinners soaks into the substrate and the pigment is carried in to seal the surface. Second coat can be normal.

 

If you don't do this the little thinner there is is sucked in leaving the thick pigment on the surface. The pigment is not 100% bonded and will eventually flake off. 

[Fruit Trader]

2 hours ago, bbabythai said:

do you know a brand of 'wall finishing cement' on sale in thailand. I need to show this to the painter (thai)

thanks

Take a look at TPI which is widely available . If the wall has a good key you can use enhanced ready mix render same as is used on AAC blocks or use one of the special skim products.

 

http://www.tpipolene.co.th/en/mortar/plastering

 

 

Edited June 10, 2018 by Fruit Trader

[JAS21]

8 hours ago, VocalNeal said:

With concrete th most important thing is the first coat which , surprise, is usually wrong here. 80% thinners, 20% pigment.

 

The thinners soaks into the substrate and the pigment is carried in to seal the surface. Second coat can be normal.

 

If you don't do this the little thinner there is is sucked in leaving the thick pigment on the surface. The pigment is not 100% bonded and will eventually flake off. 

After the concrete primer of course ...

[mogandave]

Skim-coat first...