External Installation (Paving & Cobbles)

The subbase must be made up of a well compacted layer of MOT type 1 to a minimum depth of 100mm. This should be compacted at 50mm intervals which will ensure maximum solidity and aid with achieving an even level. Following this a thin layer of washed sharp sand can be compacted to the surface of the compacted MOT type 1. Ensure a fall of 1:60 has been accurately set within the subbase to allow for adequate drainage away from the building.

The pavers must be installed onto a full bed of mortar made from 5 parts washed sharp sand and 1 part cement, mixed to a workable consistency. Prior to laying onto the mortar we advise coating the back of the paver with an SBR slurry mix made from 5 parts cement, 1 part SBR and 1 part water which will improve the
bond strength to the mortar.

It is best practice to gauge out the mortar bed and manoeuvre the paver into position rather than strike heavily with a mallet as this can lead to breakages, should there be any natural weak points. Pavers must be installed onto a full bed of mortar as per BS7533 – under no circumstances should they be spot or ribbon fixed. During the laying process it is advisable to clean away any spots of mortar or slurry as soon as possible as they can be difficult to clean when dry. After the pavers have been laid the area must not be walked on
for at least 36 hours

Ensure a fall of 1:60 has been accurately set within the substrate to allow for adequate drainage away from the building. If installing onto a solid cement substrate the minimum curing time is 28 days before installation can commence. Please note this timeframe will vary depending on site conditions and thickness of concrete.

The method for laying exterior pavers onto a concrete subbase is very similar to installing tiles internally. First the substrate must be clean and dust free as this can impair the bond strength and could lead to failure. Please note the installation must be carried out in dry conditions.

Pavers should be back buttered with a thin coat of exterior grade flexible white adhesive and laid onto a full bed of trowelled adhesive using a 10mm notched spreader. Ensure the paver is pushed into place to collapse the ridges from the notched trowel, this will provide full coverage beneath the paver and allow maximum strength for the finished patio. Under no circumstances should any of the pavers be spot fixed. Please note uncalibrated pavers should be graded prior to install and will require more adhesive in some areas.