I know it's been a while since this issue has been discussed but do you have to lathe and scratch coat or can lick and stick rock be directly applied to Icf? It's been a long time since this has been brought up maybe enough time has elapsed for more info on this. Thanks!

Posted By Half throttle on 05 Jul 2013 08:11 PM
I know it's been a while since this issue has been discussed but do you have to lathe and scratch coat or can lick and stick rock be directly applied to Icf? It's been a long time since this has been brought up maybe enough time has elapsed for more info on this. Thanks!

Most state that it's better to lathe and scratch coat. It surely can't hurt to do it with lathe and scratch coat but if you want to cut time & cost the other method might work but you have a better chance of encountering call backs due to the veneer stone breaking off. If it were my house I would do the lathe attached to the EPS attachment strips.

If you put on a Dryvit basecoat (or any other eifs system) with fibre mesh you should be okay. Make sure you rasp the foam to clear any oxidation and brush or blow off any loose material.

"If you put on a Dryvit basecoat (or any other eifs system) with fibre mesh you should be okay."


That is what my EIFS guy recommended and will be doing for my build.  I will have a stone wainscot along the bottom 42" of wall, and the acrylic stucco finish going up from there.  He recommended doing the base coat of EIFS and fiberglass mesh first, then applying the stone to it.  I decided to go with a natural sandstone instead of a manufactured stone.  A 1.5" thick flagstone is easy to work with, reasonably priced, and I just prefer real stone.

I'd be afraid that without some type of tensile reinforcement (fiberglass or metal lathe), the stone would be more at risk to impact damage and cracking.

We just did this. We tried it both ways. The lathe and scratch coat made the job easier.

If you direct apply to a base coat ICF , how will you vent or drain any water that infiltrates into the wall system ?
With lathe and scratch coat, you have a drainage plane/air gap directly behind the stone veneer.

Posted By eric monkman on 14 Jul 2013 04:44 PM
If you direct apply to a base coat ICF , how will you vent or drain any water that infiltrates into the wall system ?
With lathe and scratch coat, you have a drainage plane/air gap directly behind the stone veneer.

You know Eric, you might be right. I guess my thinking has always been that any vapour that gets past the acrylic modified base coat can safely reside in the foam gaps until it can work its way out again. If the load is to high, the concrete has ability to store quite a bit too.
I know direct applied would never work on a wood frame but there is no assembly to rot in an ICF structure. Especially if you just use foam bucks.
Thats one of the reasons I get a little concerned with this move to using wood buck and then wrapping them all up so they can never dry again. I think if you understand drainage and flashings, you can put together an exterior coat that will not let any bulk water past the skin. If you have nothing to rot in the assembly, it can stand a little more vapour than than wood and cellulose.
No test results or reports to share, just my thoughts on the subject.