Careful and proper installation is important for ensuring the long-lasting beauty of your Proline Stone Veneer. For nearly all exterior applications, required installation includes a metal lath and scratch coat (also known as cement plaster coating) over a water-resistive barrier. The water-resistive barrier generally consists of two layers of properly applied Grade D paper, which is then covered with metal lath and a mortar scratch coating (cement plaster).

What can I put stone veneer on for an exterior application?

The metal lath/scratch coating may be applied over structurally sound wall surfaces of plywood, OSB, concrete board or gypsum sheathing, supported by wood or steel studs, and over concrete or masonry walls.

What can I put stone veneer on for an interior application?

For interior applications, stone veneer can be installed over cement board, drywall, and all of the above.

How do I apply veneer to cement board or drywall?

We recommend installing metal lath and scratch coat. The metal lath will prevent the weight of the stone from pulling the nails through the cement board. See www.masonryveneer.org


Do I need to have a vapor barrier?

Yes, two layers of Grade D (15lb felt) paper is required for exterior application.


What size metal lath should I use?

2.5 pound galvanized, self-furred, metal lath is recommended.

What surface do I need metal lath on?

For all exterior applications, install metal lath and scratch coat on the structurally sound rigid sheathing.  Note: However, for clean and unpainted concrete and masonry surfaces, stone veneer may be directly applied without use of metal lath/scratch coat.   As a further note, when in doubt, install the metal lath and scratch coat.

How should the lath be applied?

The lath should be applied horizontally; Surface should be rough as you rub your hand upward. This will make the lath angle down against the wall forming little cups that will help in catching the mortar for the scratch coat.
There should be NO bubbles or bounce in the lath. 

What size nails do I use?

Coated roofing nails or screws will suffice.  Be sure to penetrate stud 1 inch, and nail every 6” vertically. Overlap the lath 4” at all seams - wrap all corners 16” or attach to stud. When corners are wrapped it is important to nail into the corner stud from both sides.  This is where the most stress will develop. If you don’t wrap the corners with lath, you will have cracks next spring!


How much mortar should I mix?

See bag instructions.

Can I Drystack the stone?

We do not recommend drystacking for exterior applications.  The grout line in traditional installations helps to secure stone and keep water out.  However, if you do choose a dry stack application, use an upgrade polymer mortar.  Be sure to order an additional 15-20% on your stone order.

What type of mortar do I need?

Type N or S.

Can I add a bonding agent to the mortar mix?

Yes, adhesion can be improved by adding a liquid bonding agent to the mortar mix. Follow manufacturer's recommendations.


How thick should the scratch coat be?

All lath should be covered with a 1/2" to 3/4" coat of mortar.

How soon can I apply stone after I finished scratch coat?

Wait until scratch coat is dry or tacky to touch.

What should I use to apply the "scratch" to the scratch coat?

Scratch coat can be roughed up with a stiff brush for better adhesion.


What guidelines should be followed when laying out the stone?

Lay out a quantity of stone near work area, blending multiple boxes to ensure proper mix of size shape & color.


What is "Buttering" the stone?

To butter the stone, completely cover the back of the stone with ½” mortar.  This will ensure a tight seal.

How hard should I push to apply the stone to the wall?

Apply enough pressure so mortar begins to ooze out to the sides of the stone.  Use a wiggle action to further set stone.  If mortar mix is made correctly, the stone should “hold” fairly quickly – less than 10 seconds.

If I need to cut a stone how do I do that?

Cutting or trimming the stones are done best with a mason blade in a skill saw, a diamond saw, a mason hammer or shingle hammer.

Where do I begin laying the stone?

Begin by snapping a line to ensure level installation (or use a level occasionally to make sure you are on track).  Use the bottom of the stone for determining whether level  - this is where the eye focuses.   If installing corners, apply corners first, starting at the bottom.

How far do I space the stones apart?

You can have larger or smaller grout joints, but typical installations are ¼ to ½ inch.  Whatever your grout joint, be sure  the stone is completely sealed around the edges with at least ¼” grout exterior

What if I get mortar on the stones?

Rinse off film or residue with 1 part vinegar / 4 parts water, using a soft bristle brush, rinse repeatedly with plain water.
Remove mortar from stone face, as necessary during installation.



Where can I get a grout bag?

Grout bags are available at any hardware store. If the bag has a metal tip remove it and cut a 3/8” hole in bag otherwise it will clog

How do I grout the joints?

After the stone has been applied to the surface, fill grout bag 2/3 full with mortar.   Fold 2 corners in and roll up end. Fill around stone in a continuous motion.

Be sure to cover any noticeable broken or cut edges with mortar


How do I "strike" the joints?

Use a striking tool to push mortar into any cavities or voids, creating a seal around each stone.

What is the purpose of striking the joints?

To fill all holes or gaps, to prevent the occupation of pests or water that may cause future problems.


What can I use to brush out the joints?

A mason or horsehair brush can be used to brush the joints

A smaller paintbrush is an advantage to getting those smaller areas

What is the purpose to brushing the joints?

Brushing the joints helps to create that clean natural stone look. It will remove any tooling marks made in the mortar.

How do I clean mortar off of stones?

A mild vinegar and water solution will work; do not use just water as it will leave a milky residue on the stone.



Does the stone need to be sealed?

It is not necessary to seal the stone.  If sealing is preferred the sealer MUST be breathable.

What should I use to seal the stone?

Use clear non-film forming – Breathable Sealer



              - Stone Mason Products

              - Any type of non-breathable clear sealer


What can I use to upkeep the look of my stone?

We recommend a mild solution of granular detergent and water. Soft bristle brushes and rinse with water

What shouldn't I use when cleaning the stone?

Do not use; acid, salt, or other de-icing materials or a wire brush, these will damage the stone.


How far should I overlap the flashing? 

Flashing should be 4” under the siding and ½” – ¾” over the top of the sill.

How should I set the sills?

Snap a chalk line and fasten 2 x 2 zinc coated angles. Butter sill and set on top of the angles to support. Apply stone underneath sill as normal, covering the exposed leg of the angle. Grout and finish joints.   After sills have set, caulk the joint along the back of the sill and the building.


How much overhang is recommended for the hearthstones? 

1/2 inch is what we recommend for both visual and strength qualities.

What do I need underneath the hearthstone?

Surface should be level. Use plywood, tar paper, metal lath and about 1/2" of mortar.

•  STONE & DIMENSIONS (approximate)

What size are the stones?

River Rock Flats                3” – 12” Diameter           1” – 3 1/4 ” Thick    
River Rock Corners           3” - 6" returns
Split Rock/ Granite             4” – 12” Diameter           1” – 11/2" Thick
Split Corners                      4" - 7" returns
Ledgestone                        4” – 10” Long                  1” Thick
                                          1 ½” – 3” High
Ledgestone Corners          4" - 8"  returns
Limestone                          4”– 14” Long                  1 ½ “- 2” Thick 
Limestone Corners            3” – 9” returns
Fieldstone                          5” – 15” Diameter          1" – 2 5/8" Thick
Fieldstone Corners            3" - 6" returns

Weatheredge                    4” – 20” Long                    1” – 2 5/8” Thick
                                         1” – 6” High
Weatheredge Corners      3"-9"


What size boxes do your stones come in?

100 sq. ft. boxes measure 40 x 48 x 30

10 sq. ft. boxes & 8 ln. ft. boxes measure 23 x 12 x 19

Norse Building Products, Inc.
Allenton Facility
536 Main Street
Allenton, WI 53002-0126
(262) 629-9330
FAX (262) 629-9982

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