Jahn M70

Limestone & Sandstone

This single-component, cementitious, mineral-based mortar is designed for the restoration of natural stone such as limestone and sandstone. Jahn M70 is completely vapor permeable at any depth and contains no latex or acrylic bonding agents or additives. The material is available in a variety of compatible, laboratory-engineered formulations which match the physical properties of the substrate being repaired. M70 provides a permanent, compatible solution which repairs and protects the beauty of natural stone. (Only Certified Installers may purchase Jahn M70.)

Features And Benefits

*Single-Component: Mixes with water only, improving quality control and consistency of application.
*Compatible Formulations: Compatibility of physical properties ensures that the mortar and natural substrate react to the environment in the same way.
*Contains No Latex or Acrylic Bonding Agents: It protects the substrate by allowing salts, water vapor, and liquid water to reach the surface, preventing failure due to salt expansion or freeze/thaw cycles.
*Tenacious Adhesion: Strong bonding capabilities without relying on synthetic bonding agents.
*Water Based: Environmentally and user safe. No solvent clean-up or disposal problems.
*Factory Controlled: No field chemistry resulting in product variation.
*Custom Colored Upon Request: Closely matches existing masonry. Choose from Standard, Premium, and Custom Colors.
*Certified Installers: Only installers with certification from Cathedral Stone Products can purchase Jahn M70 Limestone and Sandstone Repair Mortars.

Application Procedures

Surface Preparation
Surfaces to receive M70 must be sound and free of all dust, dirt, grease, laitance and/or any other coating or foreign substance which may prevent proper adhesion. Remove all loose and deteriorated masonry from the repair area using manual or pneumatic cutting tools. The area to be repaired should be cut to provide a minimum of 1/4" depth. Do not install repairs that have a feathered edge (see diagram below), incorrect installation will cause repairs to fail prematurely . Wash the prepared surface with clean water and a bristle brush to remove dust from the pores.

Section: Correct (Square Cut) Surface Preparation


Section: Incorrect (Feathered Edge) Surface Preparation

Mixing
The mixing ratio is approximately 5 to 5 1/2 parts powder to 1 part water by volume, depending on temperature and humidity. More water may be required as ambient temperature rises. The mixing may be done by hand, stirring until the mortar is thoroughly mixed. The mortar should be the consistency of damp sand. M70 may also be mixed using a slow speed drill (400 - 600 rpm) equipped with a Jiffler-type mixing paddle. For best results, add the powder to the water slowly. The working time will vary, depending upon wind, temperature, and humidity. Using excessive water in the mixture may affect the color of the repair.

Application
Moisten the substrate using clean water. Jahn Mortar should be applied to a glistening wet surface on vertical applications and a well dampened surface (with no pooling water) on horizontal applications. If the surface is allowed to dry out before applying M70, this step must be repeated. This is very important. The next step of the application is what CSP has termed the "Peanut Butter" coat. The Jahn mortar should be mixed with water to the consistency of wet putty. Apply the "Peanut Butter" coat to the glistening wet substrate approximately 1/8 inch thick. Important - To achieve proper bond, the "Peanut Butter" coat must not dry out prior to application of Jahn Mortar (5:1) mix! Build the material out beyond the surface of the original stone. After achieving initial set, scrape away excess mortar until the desired profile is reached. The waiting period for scraping should be determined on the job, due to the effects of heat, humidity, and wind on the final color. This is characteristic of all mortars, and should be determined through samples applied on site. In hot weather the darker colors may require scraping within a short time, while in cold weather the wait time may be several hours.
For the best result, wait until the Jahn Mortar is the consistency of dry sand before screeding and does not stick to the screeding tool. To achieve a rougher texture, wait longer before finishing. M70 repairs should not be floated or heavily troweled to achieve the finish, since this can alter the texture, porosity, and color of the material.
Where necessary, anchor using threaded stainless steel dowels (or other acceptable anchors). It is normally not recommended to build an armature within the repair using tying wire (or other material), or to use wire lath.

Curing
Periodically mist M70 repairs using clean water for at least a 72 hour period. The timing for initial water misting will vary with ambient conditions. Hot, dry conditions may require misting within 30 to 60 minutes. Cooler, damp conditions may require waiting several hours before beginning the curing process. Mist several times a day. Should access to the repairs be impossible over a period of time, plastic may be used to cover them temporarily. The application of plastic, however, does not remove the need for normal curing techniques.

Clean Up
Remove uncured mortar from the perimeter of the repair before it dries using clean water and a rubber sponge. Repeat several times with clean water to prevent a halo effect (staining of adjacent masonry).

Safety Requirements
It is recommended that safety goggles, gloves, and a dust mask equipped with P-2 filters (or equivalent) be worn for protection while mixing.

Limitations
* Do not apply Jahn Mortar to a frozen or exceedingly hot sub-strate. The applied mortar must be protected from extreme heat, freezing, excessive wind, direct sunlight, and rain. Ambient temperature range should be 40° F to 90° F with low to average humidity.
* Do not add bonding agents to Jahn Mortar or use them as surface preparation materials.
* Minimum thickness of mortar application is 1/4".

Packaging and Coverage
A 5 gal. plastic pail contains approx. 44 lb. of material. This will cover 0.5 cu. ft. (12 sq. ft. at 1/2" thickness).

Storage And Shelf Life
Store material in a dry area away from direct sunlight. Ambient storage conditions should be in the range of 40° F to 90° F with low to average humidity. Average shelf life is six months in original, unopened packaging.

Technical Data
Jahn M70 - Sandstone

Jahn M70 - Limestone

Warning
Not for internal consumption. Keep out of reach of children and animals.

Product data last updated 2/2000