Lumber and Siding - Using Behr knockdown finish for exterior

I recently took a gamble and decided to use Behr's knockdown finish for interior work, testing it out on our former home which we're turning into a rental property. I used both bathrooms (which formerly had wallpaper covering the walls) for the test run and was very impressed with the results. I didn't think anything could come up to the real thing when it comes to the conventional way of applying knockdown, but by and large I was sold on the idea after seeing the results. It's a little time-consuming, but on the other hand one doesn't have to tape up everything in sight with plastic to protect it as you do with the spray gun version.

Anyway, I've been wondering whether the knockdown finish could be applied to the exterior of our new home to give it a fine kind of stucco look. The existing walls are cinder block that have have been painted over, and I though that I could perhaps apply a suitable filler to the grooves between the bricks to even up all the surface, apply a proper bonding agent to the wall, then paint over it with Behr's knockdown paint. Once dry I could then apply a coat of primer followed by a good exterior paint to protect it.

Question is, does anyone know if the Behr product can stand up to exterior conditions if suitable bonded and protected. Behr specifies that it is for interior use, and maybe there's a reason why. Being water-based could be the issue?

If anyone has any knowledge or experience on the matter I'd appreciate their thoughts. It seems like a nice idea that could prove more effective and less trouble free than going the mesh route with conventional stucco. Plus I think the look might be interesting for an exterior finish.

No expert...but it's not going to work. Filling the mortar joints means applying stucco or mortar to a smooth finish first...why not just continue that over the whole exterior..not that much more work or materials I don't think.

You know the big thing now is to put a smooth finish on the regular rough stucco? Supposed to look more modern and upscale I guess.

Oh..and the interior stuff won't have the UV and weather resistance that exterior products do. It won't last unless maybe topcoated somehow..but thats even more work and materials.

Actually, I got in touch with Behr's technical support and they advised against it due to the material's inability to deal with temperature extremes - even in Florida, where I live. They said that it may or may not crack after a year or two and that it wasn't worth trying.

As for your suggestion, filling in the grooves between the bricks is one thing, but surely you couldn't use the same method to apply a stucco finish without recourse to applying wire to the exterior - which is what i was trying to avoid, as it's so tedious and troublesome when applied to an older home that already has external fixtures in place like down pipes, cables, cable boxes, shutters, etc? If I could apply a smooth stucco finish myself without using the mesh I'd give it a whirl, but my understanding is that it can't be done, especially if the cinder blocks have already been painted over. Am I wrong?

As for the smooth finish you're talking about, can an DIYer accomplish it, or does it take a pro to render a proper finish?

Absolutely not an expert on this kind of stuff...but this is what I have found from talking to folks here..and a minor amount of the work myself.

Bare block..yes its can be done pretty easy...painted I have no clue.

Smooth finish over rough stucco..pretty easy to do ....

Wish I could give ya more...you may want to post the same question in the Masonry topic..there are some real knowledgeable folks there.