Frequently Asked Questions

1. What type surface can M-Rock be applied to?

M-Rock stone can be applied over any structurally sound surface. Examples:

• Masonry or concrete walls: Stone may be applied to these walls provided the surface is clean and free from paint or sealer. Painted or sealed surfaces should be sandblasted or lathed over.
• Wood frame new construction: Wood studs should be on 16" centers and covered with building paper. Blackboard or rigid building Styrofoam can also be used. Apply metal lath to studs or backing using treated or galvanized nails or staples on 6" centers. Spread a coat of mortar over the lath.
• Wood siding: This surface should be covered with building paper to conform to local code. Then nail the lath to the surface. Apply lath right to left, top to bottom, to prevent the trowel from hanging on overlapped lath when mortar is applied. Spread mortar from left to right if you are right handed, reverse this process if you are left handed.
• Metal siding: If the metal has deep ridges in it, apply a solid backing over it before applying the lath.
• Preformed Concrete Walls: Stone can be applied to these walls.  A concrete bonding agent must be used on these types of walls. Follow the manufacturer recommendations to apply the bonding agent. 

2. What type of mortar is recommended?

S-type is recommended for best results (however, check local codes)
N-type

3. What type of supplies are required for installation?

Stone, 2.5 or 3.1 black or galvanized lath (see local code), mortar (see local code, preferably type s), felt paper or building paper (for moisture barrier), mortar color, masonry sand.

4. What type of equipment may be needed?

Mortar mixer, wheelbarrow, water hose & nozzle, trowel, shovel, soft wire brushes, air staple gun, lath cutters, hammer, staple gun (to apply felt paper), grout bag.

5. How do I apply the mortar and stone?

A scratch coat can be applied to the prepared surface but is not always necessary (check your local building codes).  If a scratch coat is used simply trowel a 1/4 inch layer of mortar over the wall and then score horizontal lines in the mortar before the scratch coat dries.  This will give the stone a rough surface to insure a proper bond. Allow the scratch coat to dry and apply stone.  If a scratch coat is not used simply apply an adequate amount of mud to the back of each stone and push the stone against the structure.  Adequate pressure and movement should be applied to insure the stone achieves proper adhesion and that there are no voids between the stone and the structure.  Let the mud dry and later fill in the grout lines. 

6. How do I dress the joints?

After the stone has been installed and enough time has passed to insure mortar will hold stones in place the joints can be filled with mortar.  The same mud used to install the stone can be used for this process.  Water can be applied to thin the mortar which will allow proper consistency so the mud will flow through the grout bag.  Be sure to keep grout mortar thick enough to hold in place inside of the grout lines.  Make sure to fill from the back to the front, a void behind the grout will cause the mortar to be weak and fall out.  To finish the grout first let it dry to a level of workability. Starting too soon will cause the mortar to be messy and not finish properly. Starting too late the mortar will become very difficult to finish.  Then with a pointer trowel and a stiff bristled brush finish the mortar by dragging away any excess grout.  Clean the stone edges and straighten the grout lines to a proper finish.

7. How should I clean up the installed stone?

Installed stone should be cleaned as soon as the mortar has dried enough to ensure the stone will hold properly.  Waiting too long will cause the mortar to dry to a finished state and the stones will not be able to be cleaned in proper manner. Simply use a stiff bristled plastic masonry brush to scrub and remove any unwanted mortar from the stone.  Starting too soon will only smear the mortar on the stone.  It is very important that this cleaning process be done on the same day the stone is installed and the same day that the grout-work is done.  No water should be used in this process, this will cause the stone to haze and will not come off the stone.  No chemicals should ever be used on M-Rock Stone.

8. How do I clean stone that has been previously installed on my home?

Use water and a stiff bristled masonry brush.  A power wash can be used if special attention is used to not damage stone or mortar during this process.