I recently removed a leaking window and paid a guy to do a brick wall in the space and then cement rendering inside nad out. 

 

Now a few weeks later the internal job is showing cracking on the rendering job. Is this anything to be concerned about? 

 

The guy at the local shop suggested I use the TOA brand shown in the pic (the one with decorplast on the front). Is this a good idea to do before I paint with sealer and primer?

 

Its too high up for me to see the exterior but assume it might have some cracks as well. 

 

Having raised this thread:

 

Some opinions were suggesting not to use household paint outside on the new cement render. 

 

I was wondering if I should use this kick ass strong stuff in the other pic- the TOA roofseal with the green pic on it. Its like a waterproof option. Or should I just stick to Dulux weathershield after using an all purpose primer?

thanks

 

That kind of cracking can be caused by rendering too early before the brick work dries sufficiently or by failing to keep the render hydrated for 3 full days after it is applied. When patching it is also important to remove the old mortar in rounded shapes, never square corners. And put chicken wire over the joint of old to new brick before rendering. Do the render job over again to eliminate the underlying problems. Otherwise more and more cracks will appear over time and you can just keep slopping on stuff and repainting over and over if you prefer.

 

I suggest  doing nothing unless there is  an urgent need to. The shrinkage visible may continue for while which when stopped can be filled in. What is more important is to see if the rendering starts to detach from the base wall as it shrinks. Easy test is to tap it gently and compare the sound to same test on stable area. Same test as for detecting poorly or incompletely adhered ceramic tiles

Yah, those almost don't even qualify as cracks.  Maybe they got a bit heavy on the render.  I also would give it a few weeks before painting.  Then, applying primer might cover them and no issue.  If not, I have made cracks like that disappear by tracing with paint, let dry, and then put final coat of paint.  IE: paint can fill this type of crack without needing special filler.

3 hours ago, bankruatsteve said:

Yah, those almost don't even qualify as cracks.  Maybe they got a bit heavy on the render.  I also would give it a few weeks before painting.  Then, applying primer might cover them and no issue.  If not, I have made cracks like that disappear by tracing with paint, let dry, and then put final coat of paint.  IE: paint can fill this type of crack without needing special filler.

Actually I think your spot on. 

 

I ended up applying a clear liquid concrete sealer and then just checked and the cracks have mostly disappeared. 

 

Next I will apply a paint sealer that is suitable for concrete

 

Then 2 coats of interior dulux paint

 

will do the same outside but have to hire a cherry picker

7 hours ago, canopy said:

That kind of cracking can be caused by rendering too early before the brick work dries sufficiently or by failing to keep the render hydrated for 3 full days after it is applied. When patching it is also important to remove the old mortar in rounded shapes, never square corners. And put chicken wire over the joint of old to new brick before rendering. Do the render job over again to eliminate the underlying problems. Otherwise more and more cracks will appear over time and you can just keep slopping on stuff and repainting over and over if you prefer.

 

I'd go with your suggestion. I think if you checked the new render by tapping you would hear hollow sounds. Off course I was wrong once in 1987.

2 hours ago, bbabythai said:

will do the same outside but have to hire a cherry picker

Check around for scaffolding to rent.  You shouldn't need more than 3 units.  We rent ours for 10 baht/unit/day.

1 hour ago, bankruatsteve said:

Check around for scaffolding to rent.  You shouldn't need more than 3 units.  We rent ours for 10 baht/unit/day.

its the neighbours we have to deal with. Its their back garden that we would have to construct it in. This project is one big headache after another for me. When its over no more for me...

Ooh Kay.  Cheers. 

11 hours ago, bbabythai said:

its the neighbours we have to deal with. Its their back garden that we would have to construct it in. This project is one big headache after another for me. When its over no more for me...

We all day that. ????