Stone Veneer Mortar Question

Old 10-13-09, 11:34 AM
Thread Starter
Join Date: Apr 2006
Location: US
Posts: 96
Received 0 Votes on 0 Posts
Stone Veneer Mortar Question

We're trying to put a stone veneer on a cinderblock wall and have been having trouble getting the stone to stick and stay in place on wall during application.

We were trying to use standard brick and block mortar so any advice on the proper material to use and tips on its application would be greatly appreciated.
Old 10-13-09, 12:33 PM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,125
Received 1,561 Votes on 1,404 Posts
I have have gotten stone to stick with a very "rich" mortar mix. I've used 2 parts type S mortar (type N might also work, but I have never tried it) to 1 part clean sand. Add just enough water to mix it together. It needs to be a pretty firm mixture.

First I pick out and fit stones that will cover several square feet of wall. Then I splash a bit of water on the block and on the back of the stones if they are absorbant. You want the wall to be moist but not wet. Then I spread a thin layer of mortar on the wall. Pushing it in hard to make sure it grabs the block. Then butter the back sides of your stone with mortar, again pressing hard to make sure it sticks. Put the stone up on the wall and push hard and tap with a rubber mallet the help get it to "suction" and stick. If done properly you can get some very large heavy stones to stick, but a rock more than 2 inches thick gets difficult.

One way to finish the mortar between the stones:
After you have the stone on the wall fill the joints with mortar until about flush with the surface of the stone. Try not to get ANY mortar on the face of the stone. Let the mortar harden for at least several hours until it is almost set. Then come back with a stiff wire brush and brush out some of the mortar. You can leave the mortar close to the surface or recessed deep depending on the look you want. If you try brushing too soon the brush will clogg and you will spread cement/mortar on the face of the stones wich will leave white mortar stains to clean off later (with a muratic acid solution).
Old 10-14-09, 11:24 AM
Join Date: Oct 2009
Location: Idaho
Posts: 14
Received 0 Votes on 0 Posts
stone veneer

definitely put a scratch coat on the block that your laying to. Also buy a bottle of "moosemilk" (concrete adhesive) to your mix... itll make your mud hotter and stickier. (1/8thC. per bag) Type "n" mortar mix is whats recommended. its naturally stickier. lastly, when you find the stone you want to lay, make sure you smear mortar also on the backside of the stone your laying. press firmly on the wall, then wiggle slightly lifting upward to press out the extra mud. when you release the stone itll settle down the wall a little. if you dont get some squishing out a little your not putting on enough mud. what squishes out between the stones is what will support your stone till it firms up. If your stone is extra large, or very hard, place shims under it. the most common problem people make is their joints are too big. keep it between 3/8" and 3/4". Finishing: Most people like a rough looking joint... after filling your joints full and allowed to be VERY firm, try using a wooden broom handle to scratch the joint out to desired depth... then brush it. A doit yourselfer will probably be messy, so expect to acid wash it if you dont like the look. If you want a glossy look(wet look) get a weed sprayer and evenly coat the stone with thompsons water seal.... after the project is done.
Also.. I dont recommend pounding on the stone, especially if its a hard stone, that will sometimes loosen up the stones youve already layed.

Thread Tools
Search this Thread
Ask a Question
Question Title: