Small holes in mono

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Ben Wilkinson

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Hi

Have rendered my own house which is in a very wet and windy place using parex monorex G00 sprayed with a monojet. This was the first job I had used the machine in anger and also the first time using mono. Anyway we sprayed it in 2 passes. Roughly troweling first pass then ruling the second pass off as we went.

Next day we scraped with an I section and rubbed up with scratch pad. There appeared to be some little bits of power in the render which hadnt mixed properly and a few little bits of paper bag so I picked them out and mixed up some of the scrapings at bottom of wall with a tiny amount of water and filled the holes with that and then rubbed up.

Anyway now after 6 months there is a few little holes that seem to have appeared. Im just gonna patch them as they are tiny but noticeable.

The question is why am I getting these voids in the render? Do I need to work it more on first or second coat with h section or spats? Also was considering using a serrated h section and going over with spat is this the best way? Not realy sure if the holes are air pockets or just bits of power not mixed properly that have been washed out by rain.

Thanks in advance.
 
Hi

Have rendered my own house which is in a very wet and windy place using parex monorex G00 sprayed with a monojet. This was the first job I had used the machine in anger and also the first time using mono. Anyway we sprayed it in 2 passes. Roughly troweling first pass then ruling the second pass off as we went.

Next day we scraped with an I section and rubbed up with scratch pad. There appeared to be some little bits of power in the render which hadnt mixed properly and a few little bits of paper bag so I picked them out and mixed up some of the scrapings at bottom of wall with a tiny amount of water and filled the holes with that and then rubbed up.

Anyway now after 6 months there is a few little holes that seem to have appeared. Im just gonna patch them as they are tiny but noticeable.

The question is why am I getting these voids in the render? Do I need to work it more on first or second coat with h section or spats? Also was considering using a serrated h section and going over with spat is this the best way? Not realy sure if the holes are air pockets or just bits of power not mixed properly that have been washed out by rain.

Thanks in advance.
When we do 2 passes we use the serrated edge on the 1st pass then spat on the 2nd. That should stop air pockets but if they are coming in the 2nd pass you can use the serrated edge then spat. Not sure why there would be powder in it but any holes try to use the scrapings without any water at all for the exact colour. Hope this helps.
 
The small holes are air pockets which was covered with a very thin wall of render. A serrated straight edge will help avoid this. Rule off flat then flatten as soon as with a spat.

The bits of paper happens. It does to me anyway.

Didn't know you could get a 1800 I section? Everyone to their own.
 
The small holes are air pockets which was covered with a very thin wall of render. A serrated straight edge will help avoid this. Rule off flat then flatten as soon as with a spat.

The bits of paper happens. It does to me anyway.

Didn't know you could get a 1800 I section? Everyone to their own.
The paper from the bags does my head in to Rigsby ,if they were £50 notes i would not mind so much :RpS_biggrin:
 
like said bunch the scrapings together into a clump and push into any tiny holes then scrape again lightly.

powder falling away sounds like the bags could have been stored badly - got wet or damp, been in the freezing cold or out of date.
 
Thanks for advice guys. Aye bags were sitting in container for quite a while so may have got slightly damp. I shall try serrated edge. so do you guys rule off both coats then? I thought first pass was just to kill suction so just horsed over it quickly with a trowel.
 
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