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Celtik Wall - Installation Instructions

The following are the basic steps involved in constructing a gravity wall from Celtik Wall. Celtik Wall is designed for walls up to 42" (1.1 m) in height, when built with an 8° batter (slope). Vertical walls may be built to a maximum height of 21" (0.55 m).


Step 1 - Plan:
With your final design in hand, begin to establish the wall location and proposed grades. Locate all utilities and contact local utility companies before digging. Mark a line where the front of the wall will be placed - if building a battered wall, keep in mind the 3/4" (19mm) setback.

Step 2 - Excavate:
Excavate a trench down to the foundation grades specified in the design. The front of the trench should be 6" (150mm) from the planned face of the block. The trench should be a minimum of 27" (675mm) wide (front to back) and 11" (275mm) deep. This depth assumes one 135 mm unit or 1-1/2 90 mm units are buried plus the compacted granular base minimum depth of 6" (150mm). The rear 6" (150mm) of the trench is excavated to account for the drainage layer. Excavations should be conducted in accordance with local codes.

Step 3 - Verify Foundation Subgrade:
Once the foundation trench has been excavated to the specified elevations, the native foundation soil must be checked to ensure that it has the required allowable bearing capacity specified in the design.

Step 4 - Prepare the Compacted Granular Base:
Start the base at the lowest elevation of the wall. The base should be composed of well-graded, free-draining (less than 8% fines), angular granular material (5/8 minus or 3/4 minus crushed rock), and compacted to a minimum of 98% SPD. The minimum base thickness is 6" (150mm) or as required to reach competent founding soil. Geotextile might be required under the granular base. The minimum base dimensions are 21" (525mm) wide (front to back) and 6" (150mm) deep. The additional 6" (150mm) trench width allows for the placement of the drain.

Step 5 - Step the Base:
When the grade in front of the wall slopes up or down, the base must be stepped to compensate. Working out the stepped base as the wall steps up in elevation, the foundation steps must be located to ensure the minimum embedment is achieved. The height of each step is 3-1/2" (90mm) when using 90 mm units or 5-1/4" (135mm) when using 135 mm units or mixing both sizes. If building a battered (sloped) wall, the 3/4" (19mm) setback must be accounted for at each step.

Step 6 - Place Filter Cloth:
Lay the approved filter fabric (geotextile) along the bottom of the rear of the trench and extend up the exposed excavation to the proposed wall height. Leave adequate material at the top to fold back towards the wall (completely containing the drainage material). Stake the filter cloth against the slope during construction.

Step 7 - Place the Drain:
Various options for drain placement may exist, depending on how the pipe is to be outlet. The drain may be outlet through the wall face or connected to a positive outlet (sewer). The drainage system is extremely important and outlets must be planned prior to construction. In the case of connecting to a positive outlet, the drain should be placed at the lowest possible elevation and sloped at a minimum of 2%. At the rear of the base, allow the granular material to slope down on the sides towards the drain trench. In the 6" (150mm) area behind the base, place the approved drain tile (perforated drain with filter sock) on top of the filter cloth and minimal granular coverage.

Step 8 - Choose a Block Size:
Choose from one of the following wall arrangements: (1) 90 mm units only, (2) 135 mm units only or (3) Combination of 90 mm and 135 mm units. See Installation Patterns for an example of each option.

Step 9 - Place the First Course:
Use the 17-1/4", 13-3/4", or 10-1/4" units for the base course. Set the first unit, making sure that it is level. Lay additional units, checking front to back and side to side alignment with the first unit. Even if the selected arrangement is a combination of 90 mm and 135 mm units, the first course must contain only one size of unit (90 mm or 135 mm). At this stage, no connectors are used.

Step 10 - Celtik Connectors:
The dual-position Celtik Connector System allows for the construction of vertical or 8° battered walls. Celtik units are delivered with two (2) different connectors: a basic connector with blades and a connector without blades - designed for the construction of corners and vertical walls. Either can be used for the construction of a straight wall. Celtik Connectors are inserted in the underside of the Celtik units - click here for an illustration. This is why units are placed bottom up on the pallet.

Step 11a - Additional Courses on Walls of Either 90mm or 135mm Units
First, insert connectors in units to be installed. Use appropriate slots, depending on whether the wall is to be vertical or 8° sloped (refer to Illustration under Step 10). When installing additional units, choose a width that will span the joint of the units below. Celtik Wall units may be used vertically. Use a 6-3/4" unit to match two 90 mm courses, and a 10-1/4" unit to match two 135 mm courses.

Step 11b - Additional Courses on Walls Combining 90mm and 135mm Units
Carefully distribute different sizes of units to give a well-balanced, natural look to the layout. To integrate vertical elements, split 17-1/4" units (90 or 135 mm high) into halves. A split half covers the total height of a 90 mm unit plus a 135 mm unit. Note: When combining 90 mm and 135 mm units, spaces may appear between some units in the structure.

Step 12 - Backfilling:
Every two (2) courses, a free-draining, 3/4" (19mm) clear stone drainage material is placed immediately behind the wall facing and compacted with a light manual tamper. The drainage layer must be a minimum of 12" (300mm) thick and protected from the native material by the filter cloth.

Step 13 - Continue Stacking & Backfilling:
Continue stacking units and backfilling as described in Steps 9 & 10 until the desired height is reached, based on the design.

Step 14 - Place Cap Units:
Either the 90mm Cap Units or the wall units can be used to cap the wall, depending on the alignment of the wall and desired look. A layer of concrete adhesive must be applied to the top course in order to fix the cap units in place. Place the cap unit firmly on top of the adhesive, ensuring both surfaces are free of debris, and apply pressure to secure. Follow adhesive installation guidelines.

Step 15 - Encapsulate the Drainage Layer & Finish Grading:
Fold the excess filter fabric over the top of the drainage layer and extend up the back face of the cap units. Ideally, place an impervious layer of soil on top of the filter fabric and compact manually, providing for the required grading and/or swales. For other treatments such as pavers, concrete, or asphalt, care must be taken to ensure that heavy compaction/paving equipment remains a minimum of 40" (1.0m) from the back of the cap units. Slope the surface above and below the wall to ensure water will flow away from and not accumulate near the wall units.