Contact Us

Get in touch—we’re here to help

Contact Us

Contact Us

let's work together

Get a Quotation

    FAQs

    "Our FAQ section covers key questions about the Keystone system and our services. Find answers on installation, components, drainage, wall finishing, repairs, and more. Explore to learn how we support your civil engineering projects."

    What are the Keystone components?

    • Concrete blocks

    • Fiberglass Pins

    • HDPE Geogrids

    • Cap Units

    What are the installation steps?

    1. Lay down the precast concrete units on top of a PC foundation (15 – 20 cm thick, 60cm width) at a level that is a minimum of 5% from the wall height (buried height) to prevent any lateral movement. For heavy loads on top the buried height changes to a max of 10%.

    2. Backfilling using fine gravel behind the wall for a distance of 30 cm, max size of 20mm.

    3. The sand or sand with a percent of gravel for the rest of the reinforced backfilling area.

    4. Layers are compacted to 95 Standard Proctor. Compacted layers are 30 cm in thickness or less.

    5. Place HDPE geogrids on top of the compacted soil. HDPE geogrids are installed from the front on top of the fiberglass pins (which penetrate the geogrids) and from to back, geogrids are fixed horizontally using a U-shaped steel bar with a 25cm length per leg.

    6. Repeat the above steps (1-5)

    How to install the drainage system inside the Keystone wall?

    • Place the pins in the rear pin holes.

    • When required, install drainage pipe behind wall unit and outlet drain to storm system or daylight as required.

    • Once the pins and drainage pipe have been installed, provide 2cm crushed stone unit drainage material to a minimum total distance 60cm from the wall face. Fill all open spaces between units and open cavities/cores with the same unit drainage material.

     

    What about the construction of Keystone corners & curves?

    • A corner is typically constructed as either an outside 90° corner, inside 90° corner or acute outside corner (between 75° to 90°).

    • When a wall needs to make a turn greater than 90° it is recommended to install a radius curve for the wall.

    • For curves in the wall, Keystone units typically have a minimum radius depending on the face style, which is outlined later in this section by unit type.

    What are the options of the wall finishing at the top?

    • A Keystone retaining wall is not complete without the “capping touch.” as the Keystone blocks have open voids, making them an aesthetically undesirable finish for the top of the wall.

    • Keystone offers the cap units, available in various combinations of facial finish and degrees of angled sides

    • You may also finish your wall with a precast decorative concrete finishing option.

    How to install a concrete stair within the Keystone system?

    • Keystone walls can easily be constructed to incorporate concrete stairs within the wall systems.

    • The stairways can be designed to be incorporated into reinforced soil of the wall or projected out from the wall face.

    • Construct the Keystone wall as per design, where a stairway is proposed, create a 90º outside corner with Keystone straight face and corner units. Construct the concrete stairs as the project plans, making sure they include a ½ inch expansion joint between the stairs and the Keystone units.

    How to repair damaged or cracked units in Keystone wall?

    • For minor cracks, fill the opening with construction epoxy and dust lightly with concrete material of similar color. Use a ground up piece from another Keystone unit.

    • To replace a broken block, dismantle units down to broken unit(s), replace with new unit(s). Rebuild wall placing corefill and backfill with necessary light compaction until capping of wall as shown in above detail.

    What about the planting roots while using the Keystone system?

    • All planting offsets shall be a minimum of 2 feet + the opening diameter as measured from the face of the wall.

    • Lateral spacing between openings shall be a minimum of 3 x opening diameter.

    • Only the top two layers of geogrid may be cut to allow planting of tree balls. Avoid disturbance of adjacent reinforcement.

    • If trees are spaced closely together and cutting of geogrid becomes excessive, consult with your Keystone representative.

    • Extreme care shall be taken if installing irrigation systems directly behind the wall so as to not damage the soil reinforcement during installation or have potential leakage into the retaining wall system.

    • Leaking irrigation lines can saturate the backfill and create hydrostatic pressure and wall movement.

    • Utilize a root control barrier as required to avoid root pressures or growth through the Keystone concrete units.

    How to make a drawing or logo at the Keystone facing?

    • Add distinctive detail to any Keystone retaining wall. For subtle design accents vary the texture of units in geometric patterns while maintaining the Keystone unit color choice.

    • Texture combinations can be sculptured rock faces mixed with straight split units, smooth face units or corduroy units.

    • Dramatic accents can occur when combining units of complementary and or contrasting color schemes.

    What about the types of fences which can be installed at the top of the Keystone wall?

    • Fences can be placed at the top of a Keystone wall using barriers, guard Rails, fence posts, steel and wooden fences placed behind and inside the Keystone units.

    Inquiry Form