Trenwyth / Astra-Glaze-SW+

Astra-Glaze-SW+ Specification

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Part 1 General

Submit color samples for selection from manufacturer”s series. Submit product literature, certifications, test reports, full size sample(s) of each color specified or selected. Custom colors are available. Contact Trenwyth (800-233-1924) for details.

Quality Assurance:
All glazed masonry units shall be Astra-Glaze-SW+ units manufactured by Trenwyth manufacturing facilities. Glazed concrete blocks manufactured in Pennsylvania shall be lightweight units conforming to ASTM C90. Glazed concrete blocks manufactured in Arizona shall be medium weight units conforming to ASTM C90. The glazed surface shall have a smooth satin-gloss finish, externally heat-polymerized cast-on facing conforming to ASTM C744-08 and all applicable Federal Specifications. All Astra-Glaze-SW+units are manufactured with an approved integral water repellent CMU admixture.

All Astra-Glaze-SW+ are manufactured with pre-consumer recycled material.

Fire Resistance: Fire rated for up to 4 hours. Define hourly ratings required by NCMA TEK Notes, .

Field Constructed Mock-ups: Construct a sample panel, no less than 4′ x 4′, of units of each color and size to be used in the project.

A full size unit is required to illustrate color and texture for approval. Manufacturer requires that a sample panel be installed at the jobsite prior to installation of any Trenwyth product. This panel will represent both the quality of the product and the workmanship to be expected for the project. The panel must be approved by either the owner or architect for the project. Manufacturer will provide 4″ units for a 4′ by 4′ sample panel at no cost for the material (excluding freight to site).

Delivery, Storage and Handling:
Glazed masonry units shall be delivered to the jobsite on banded pallets with individual protective covers on each glazed block face. Keep protective block covers on the blocks until installation. Store pallets in single stacks on level ground and cover with waterproof covering (e.g., tarpaulins) to protect the blocks from inclement weather. Handle blocks carefully to avoid breakage and damage to the finished surface.

Project Site Conditions:
Protection of Work: Cover walls each day after installation to keep open walls protected and dry. After units are installed they should be protected from damage by other trades performing operations that can stain or otherwise damage the finished surfaces by covering walls with plastic. Corners should be protected from damage after installation by covering them with plywood.

Part 2 Products

Product Name
Astra-Glaze-SW+® glazed concrete masonry units
Astra-Glaze-SW+® recycled glazed concrete masonry units

Anchor Concrete Products (800) 233-1924
One Connelly Road, Emigsville, PA 17318

Superlite Block (800) 331-9823
4626 N. 42nd Avenue, Phoenix, AZ 85019

Related Materials:
Colored matching or contrasting mortar is available from manufacturer. Consult NCMA TEK Notes, for mortar type and specifications. Use manufacturer-approved matching water-repellent mortar additive, following manufacturers instructions, in all exterior mortar. Consult manufacturer for recommendations.

In areas that are exposed to excessive moisture, we recommend joints to be raked and filled with BONSAL B-7000 EPOXY. See Mortar Bedding and Jointing for details.

Sizes and Shapes:
Actual facing dimensions shall be 7-3/4″ x 15-3/4″ forming a 1/16″ lip around the edges of a modular 7-5/8″ x 15-5/8″ block. Nominal 2″, 4″, 6″, 8″, 10″ and 12″ standard block thickness shall be used as required, as well as standard and special block shapes. Basic units may include stretchers, jambs, caps and cove bases. Other possible face dimensions are nominal 16″ x 16″, 12″ x 12″, 8″ x 18″, 4″ x 16″, 8″ x 8″. Semi-solid and solid units shall be used where specified and/or shown on the drawings.

Masonry Cleaners:
Carefully following the manufacturer’s instructions, we recommend the use of Custom Burnished Masonry Cleaner by PROSOCO (dilute 1 part to 3 parts clean water). Available from manufacturer.
Do not powerwash.

CAUTION! The following solvents must never be used as they may damage Astra-Glaze-SW+ block facings: paint remover, lacquer thinner, epoxy thinner, methylene chloride, acetone, muriatic acid. Contact your Trenwyth representative for recommendations for hard to clean areas.

Part 3 Execution

Laying Masonry Walls
Draw blocks from more than one pallet at a time during installation. All exterior mortar shall include manufacturer-approved water-repellent additive added to each batch in the appropriate dosage rates for mortar type (M, S or N) per manufacturer’s instructions. Refer to NCMA TEK Notes, for Hot and Cold weather construction practices.

Lay Astra-Glaze-SW+ blocks with the faces level, plumb and true to a line strung horizontally at the glazed face. Install only quality units; reject all defective units, as defined in ASTM C744. Units shall have uniform face joint dimensions of 1/4″ both horizontally and vertically. Tool joints neatly after they are finger-hard to make them straight and uniform. Size and place cut pieces appropriately to maintain consistency and bond. Complete masonry construction using procedures and workmanship consistent with the best masonry practices.

Lighting: Provide adequate lighting for masonry work by placing all lighting at a reasonable distance from the wall for even illumination. Do not use trough lighting.

Base Course: Align base course properly on the floor slab.

Cove Base: Keep the cove base tight to the slab if vinyl floor tile is to be installed. For thicker flooring, raise cove base units to the desired height.

Cutting: Make all unit cuts, including those for bonding, holes, boxes, etc., with motor driven masonry saws, using either an abrasive or diamond blade. Cut neatly and locate for best appearance.

Mortar Bedding and Jointing:

  1. Lay units with full mortar coverage on head and bed joints taking care not to block cores to be grouted or filled with masonry insulation.
  2. Tool all mortar joints when thumbprint hard into a concave configuration.
  3. Care should be taken to remove mortar from the face of masonry units before it sets.
  4. Tuckpoint the joints of scored units for proper appearance. All exterior scored units must be tuckpointed to prevent water penetration. Rake back the joint when epoxy (Bonsal/Laticrete) is used on select jobs that require better moisture prevention.

Various masonry mortars may be used with Astra-Glaze-SW+ concrete masonry units depending on specific structural requirements for the finished walls. We recommend a matching water-repellent mortar additive (available for purchase from manufacturer). Follow manufacturer’s instructions in all mortar applications.

Epoxy Finished Joints:
In areas exposed to excessive moisture, make sure to tool mortar joints with a minimum of 1/4″ and tuckpoint with an approved water-resistant grout. A typical tuckpointing grout is BONSAL® POLYMER MODIFIED SANDED TILE GROUT mixed with the BONSAL B-7000 EPOXY. Do not add water or anything else in addition to the B-7000, which will make it a 100% solid enabling it to be acid and stain resistant.


Flashing of Masonry Work:
Install flashing at locations shown in the plans and in strict accordance with the details and the best masonry flashing practices.

Weep Holes and Vents:
Install weep holes and vents at proper intervals at courses above grade and at any water stops over windows, doors and beams. Consult NCMA TEK Notes, available at, for additional information on flashing.

The glazed facing shall conform to the requirements of ASTM C744 when viewed from a distance of five (5) feet at right angles to the wall with normal lighting. The concrete masonry units on which the glaze is molded shall conform to the requirements of ASTM C90.

Keep walls clean daily during installation using brushes or rags and a clean damp cloth. Harsh cleaning methods after walls have been erected may mar the surface of the blocks. Do not allow excess mortar lumps or smears to harden on the glazed surfaces. Remove green mortar with a dry cloth. Do not use steel wool, sandpaper or other abrasives.

Final Cleandown:
Clean the completed walls with Burnished Custom Masonry Cleaner by PROSOCO 3:1 solution, carefully following manufacturer’s washdown instructions including thorough rinsing. Do not use acid or abrasives on the glazed surfaces.

Astra-Glaze-SW+ units, properly installed and cleaned, need virtually no maintenance other than routine cleaning with typical non-abrasive household cleaner. Graffiti, paint or dye may need special cleaning methods and products such as Trenwyth Graffiti Wizard® environmentally friendly cleaner. Contact manufacturer for specific cleaning recommendations. Do not powerwash.

Installation Recommendations:

  • For walls with a glazed finish on both sides, use two single-faced units. Because masonry units are typically installed aligning one side, the second side of double faced units is almost invariably misaligned. Double-faced units are not recommended. Manufacturer accepts no responsibility for face alignment.
  • Cavity wall construction is recommended for exterior walls, with proper flashing, venting and weep holes.
  • For best appearance, use stack bond construction when stack bond appearance is desired (as opposed to scored units in running bond).
  • All exterior mortar joints must contain a manufacturer-approved water repellent additive.
  • For best appearance and water resistance, tuckpoint scored joints on interior and exterior applications.
  • Colored matching or contrasting mortar / epoxy is available when using colorful Astra-Glaze-SW+ units. Contact your Trenwyth representative for information.