cracks in scratch coat for stone veneer?
chris686
| Posted in General Discussion on
I’m just starting on the manufactured stone veneer on the outside of my house. I applied a scratch coat about 1/2 or 3/4 inch thick on metal lath over housewrap on a test section, and cracks developed throughout as it dried.
None of the cracks are more than 3/32 wide, and when I push on the dried scratch coat, the whole thing is solid. We have pretty mild summers here (Western Washington)– daytime highs around 70 and maybe 50% humidity, plus this section wasn’t in direct sunlight for most of the day.
Is this normal? A problem? Was my scratch coat too dry? Should I wet it after I apply it? Any feedback would be appreciated. Thanks
Replies
Chris,
Don't worry about it. It may be less than perfect, but will do its job just fine. The paper behind it is the drainage plane, so the scratch coat is only there to provide a toothy bonding surface for the stone veneer.
Bill
you mixed a little too weet and it dryed a little too fast, needs to keep damp while curing. You are seeing shrinage cracks.
Other than that, if the mix was right, you are fine.
That's one reason it's called the scratch coat
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
That's fairly normal. That's why you put on a scratch coat, anyway- it's a good warm up for the finish coat (if you're stuccoing).
zak
"so it goes"
not enough nailing for the lath....
too wet of a mix...
dried too fast...
if you are nailed up in 1st rate mode don't worry.....
pull on the scratch coat .. it it moves you need more nailing...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
Shooda kep it wet fer a week.
Then the cracks would be too small to see. Cure it for 28 days and it won't crack.
All is not lost.
Use as is, or, keep it wet for a week, add another coat, and this time cure it properly. I'ld cure it at least a week before hanging any stone off it.
Cement products require a supply of moisture to cure. 28 days of it to reach stated strength.
Thanks everyone for the advise. Glad to see I didn't mess up too badly. This is one of the reasons I started off with just a small little section (I have 700 square feet to go). For the rest of it, I'll make sure to spray a little water over it as it cures.
Thanks again,
Chris