Recessed covers and frames installation guide

If replacing an existing cover, ensure that there is sufficient depth to accommodate the new frame plus 20-40 mm of bedding mortar. If necessary, remove material from the top of the chamber to achieve this, taking care to avoid debris entering the chamber. Clear away any loose or flaky material to leave a sound surface for the new mortar bed.

Remove the cover from the frame as follows:

a) Remove the M8 countersunk cover locking screws using a flat head screwdriver (Fig 1) store the screws safely in a clean environment for refitting later.

b) Insert the ‘J’ shaped keys (code KEYSRECESSED) in the horizontal position (Fig 2).

c) Rotate the keys into the upright position to lock them into the lifting eyes (Fig 3).

d) Separate the cover and frame.

Trial position the frame over the manhole chamber, ensuring that it can be positioned in such a way that there is no part overhanging the chamber opening, unsupported framework can lead to premature cover failure. (Fig. 4).

Set the top of the new frame to the required finished floor level, this can be done with a straight edge from existing finish if available (Fig. 5) or if not, with a laser level or string lines. Temporarily shim the frame at the correct height to gauge the depth requirement of the mortar bed.

Lay down a mortar bed large enough to fully support the frame, leaving it slightly proud for tamping.

Position the frame on the mortar bed in its previously established location and carefully insert the cover. Loosely replace the 4 locking bolts to ensure they are in line but do not tighten at this stage, doing so may distort the frame. Tamp down until the top of the cover and frame sits at the required finished level on all sides. (Fig. 6). Check that the cover sits in the frame with no rock and that the top of the cover and frame are level, making any necessary adjustments to the bedding to achieve a good, non-rock fit.

Allow the mortar to stabilise and then carefully remove the locking screws and cover. Point the inside of the frame and remove any excess mortar, also haunch around the outside of the frame leaving sufficient depth for any subsequent finishes (vinyl, tiles etc.) (Fig. 7).

Return the cover to the frame and refit the locking bolts.

Allow the mortar bedding to fully cure before proceeding.

Screed / concrete up to the outside of the frame, leaving depth for subsequent adhesives and floor finishes if required (Fig. 8).

Screed / concrete the inside of the cover recess, again leaving depth for subsequent floor finishes (Fig. 9). Note: The maximum loading capacity of 2.5 tonne SMWL can only be achieved when the cover is fully filled to the top edge with grade C25 concrete. A stepped strickle is easily made and assists with filling the cover where depth for additional floor finishes is required (Fig. 10).

Fully tighten the locking bolts and add floor finishes as required (Fig. 11).