wet dash render

[albundy89]

Hi, just attempted this,first time for years, mix was 6 peas 2 sand 1.5 lime 1 cement.
Tried a couple of sample panels first, one turned out fine but the other has what looks like tiny hairline cracks,maybe 5 to 10mm long now that it is drying out after 24 hrs.
Anyone any ideas as to the cause. Thanks.

 

[roy c]

What back ground did you put it on?

 

[albundy89]

5 sand 1 lime 1 cement scratch coat
6 sand 1 lime 1 cement top coat and dashing coat applied when almost dry to touch.
Any ideas what happened? thanks.

 

[Alastairreid]

What back ground did you put it on?

 

[albundy89]

Dense concrete block background suitably watered before and between coats.

 

[darrington]

Drying out too quick maybe? or slumping a little??, Are the small cracks vertical, or horizontal, are they all over that particular panel, or just here and there? A picture would show/tell an awful lot.

 

[roy c]

The mix I use for rough casting is 6-1-1 scratch and also 6-1-1 for the butter coat and the wet mix 4-2-1-1 (pebbles or aggregate-sand-lime- cement). I dampen the scratch coat down before applying the butter coat (tight coat)just a few square metres at a time then throw the wet slurry mix on. Maybe the butter coat was too dry. Or theoretically your mix was 8-1.5-1 maybe a bit weak ..

 

[albundy89]

Thanks for the replies,cannot quite figure this one out as all 3 panels were treated the same only difference was the type/size of peas used to check out different textures.
Unfortunately area has been scraped off prior to dashing again, so no photos.
Will try to remember to update after job is done with results.

 

[roy c]

Was it windy? Or sunny ? That panel may have caught the sun as it moved round or maybe this was the only panel the wind hit? Must go off to work now