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NBS Source


Suitable for tree pits and walkways.


A UV stable polyurethane resin with enhanced UV resistance designed to bind natural and recycled aggregates to provide a fully bonded and attractive porous surface to tree pits or walkways.

Features and benefits:

  • Installed flush with the surrounding paving areas - won't become a litter trap like traditional tree grilles.
  • The open texture provides a highly porous resin bound surface, allowing the tree roots access to both air and water penetration. 


Areas to be filled with resin bonded aggregate must be clean and dry with a minimum infill depth of 50–100 mm, 25 mm depth if areas are not to be walked on. A quantity of loose chosen aggregate to be mixed with the PU Addastone TP UV RESIN should be applied to the area at a depth of 25-50 mm below the top surface level depending on expected pedestrian traffic loading.

Aggregates used must be washed, clean and dry with a minimum grading of 2–5 mm, for greater percolation of water a minimum grading of 6–10 mm should be used. A suitable protective collar should be installed 50–100 mm from the base of the trunk to allow for growth.

Mixing/ application:

The contents of PU Addastone TP UV Resin Part ‘B’ should be added to container PU Addastone TP UV Resin Part ‘A’ and thoroughly mixed together using a drill and paddle or similar. Immediately add catalyst Part ‘C’ and thoroughly mix again using the drill and paddle. The mixed PU Addastone TP UV Resin should then be poured on to the chosen aggregates and placed in a forced action mixer and mixed thoroughly until all aggregate is coated in resin. The approximate ratio of aggregate to resin is 1 kg PU Addastone TP UV Resin to 20–25 kgs of aggregate. For a stronger bond, a ratio of 1 kg PU Addastone TP UV Resin to 20 kgs of aggregate.

The mixed resin and aggregate should then be placed in the area to be filled and trowelled to a flat finish. While the resin is still wet apply a scattering of kiln-dried quartz or similar to improve skid resistance.

Do not apply in wet conditions. Recommended temperature of application should be 5°C up to 30°C. Allow to cure for 3–6 hours at 18°C.

It is recommended not to apply the resin bonded aggregate to the area between the tree trunk and the protective collar; fill gap with loose aggregate or Addaflex-R to allow the tree space to grow. If the resin bonded finish is to be applied up to the tree trunk apply thinly and feather off as required to the maximum depth of the aggregate used 6–10 mm.

General information





Pr_35_31_05_70 Resin-bonded aggregate surfacingsPrimary


Q10/305 Tree grilles and surrounds

Q22/175 Proprietary pedestrian paving

Q22/185 Proprietary surface treatment to existing paving

Q22/365 Proprietary surface treatment

Specification data - Resin-bonded aggregate surfacings




Addastone TP.


A range of aggregates and recycled aggregates is available from various aggregate suppliers. Contact Addagrip for details and advice on the suitability of the chosen aggregate, particularly in relation to the porosity.


Size (nominal)

6–10 mm.


Brittany Bronze.

Corn Flint.

Dorset Gold.

Red Granite.

Rhine Gold.

Silver Grey Granite.

Trent Pea Gravel.




Addastone TP Resin.


Light Pale Yellow (translucent).

PU Addastone TP UV Resin is Light Pale Yellow (translucent). Finish colour will depend on the chosen aggregate.

Slip resistance – water wet (minimum)

PTV of 43.


25 mm.

For areas with no foot traffic.

50 mm.

For medium foot traffic.

75 mm.

For heavy pedestrian foot traffic.

Digital objects

Platform Compatible Version Certified to




Download now from NBS National BIM Library

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