Block paving technical specification
Standard Contract Documentation
Workmanship and materials specification clauses. To be read with Preliminaries/General Conditions.
TYPE(S) OF PAVING
110 CONCRETE BLOCK PAVING
As Section Q20
Thickness: To Engineer's specification
Blocks: To BS EN 1338: 2003
Reference: Royal Forest Range, Chartres or EcoGranite range of paving, setts and cobbles
Thickness: 50, 60, 70, 80 or 100mm
Setting Out: As Architect's Drawing
Bond: To be specified.
210 LAYING GENERALLY
Ensure that the sub-base is reasonably accurate and to specified gradients before laying paving.
Cut blocks neatly and accurately without spalling to give neat junctions at edge restraints and changes in bond.
Select blocks from three separate packs in rotation to minimise colour variations.
Lay blocks on a well graded sand bed and vibrate to produce a thoroughly interlocked paving of even overall appearance with regular sand filled joints and accurate to line, level and profile.
Before placing orders submit for approval representative sample(s) of Formpave products.
240 ADVERSE WEATHER
Do not use frozen materials or lay sand bedding on frozen or frost covered sub-bases.
Protect stockpiled bedding sand to ensure it does not become saturated.
Protect uncompacted areas of paving from heavy rainfall.
250 ACCEPTANCE OF BASE
Before starting work ensure that the base is sound, clean and suitably close textured.
The levels and falls of the base are as detailed, within the specified tolerances of ± 20mm.
260 LEVELS OF PAVING
Permissible deviation from specified levels to be ± 6mm generally. Paving at drainage outlets to be set 6mm above outlet.
Sudden irregularities are not permitted. Not more than 10mm deviation over three metres, when measured with a three metre straight edge equipped with feet.
280 SAND FOR BEDDING, GENERAL
Sand complying with BS 7533 Part 3:1997 Table D.1 and D2.
The sand should be hard, sound and resistant to degradation. Soft sand or calcareous sand should not be used.
Obtain sand from only one source and ensure that all sand supplied has consistent grading.
Maintain at an even moisture content which will give maximum compaction during any laying period.
290 SAND FOR JOINTING, GENERAL
Sand complying with BS 7533 Part 3: 1997 Table D.3.
Do not use sand that contains organic impurities or stains the blocks.
300 LAYING BEDDING
Lay, level and compact a layer of bedding material to a thickness of approximately 35mm, then lay and screed to level a further uniformly loose layer. This should have sufficient surcharge to give the required finished levels and an overall bedding thickness of not less than 50mm after compaction of the paving.
Subject to approval of accuracy and regularity of the finished paving, the bedding may be laid in a single layer thickness after compaction to be not less than 25mm at any point.
Do not leave areas of bedding exposed, proceed with laying immediately after screeding.
Maintain a prepared area of bedding not less than 1 metre and not more than 3 metres in advance of the laying face at all times and not more than 1 metre at the conclusion of any working period.
Do not deliver bedding sand to working area over uncompacted paving. Prevent disturbance to the bedding course by pedestrian or wheeled traffic.
Fill, re-screed and re-compact any parts of the bedding layer which has been disturbed.
310 LAYING PAVERS
Commencing from an edge restraint, lay blocks hand tight, do not use mechanical force to obtain tight joints.
Place blocks squarely with minimum disturbance to bedding sand.
Supply blocks to laying face over newly laid paving but stack at least 1 metre back from laying face.
Do not allow plant to traverse areas of uncompacted paving.
Continually check alignment of blocks by the use of string lines to ensure the maintenance of accurate bond.
Infill with cut blocks as appropriate at edge restraints as work proceeds.
Wherever the type of bond and angle of edging permit, avoid very small infill pieces at edges by breaking bond on the next course in from the edge. Avoid using cut blocks smaller than one third full size.
325 CUT BLOCKS
Cut only sufficient blocks for use in the current operation.
Cut blocks using a block splitter or saw. When using the block splitter set block at a slight angle, to ensure that the exposed face is larger than the underside.
330 VIBRATING PLATE COMPACTOR FOR BLOCK PAVING
Plate Area: 0.35 to 0.50 m2
Force Range: 75 to 100 kN/m2
Frequency range: 75 to 100 Hz
340 COMPACTING AND JOINTING, GENERAL
Thoroughly compact blocks with vibrating plate compactor as laying proceeds but after infilling at edges. Apply the same compacting effort over the whole surface.
Do not leave uncompacted areas of paving at the end of working periods, except within 1 metre of unrestrained edges.
Check paving after compacting the first few metres, then at frequent intervals to ensure that surface levels are as specified; if they are not, lift blocks and re-lay.
Brush kiln dry sand into joints. Re-vibrate surface and repeat as required to completely fill joints.
Avoid damaging kerbs and adjacent work during vibration.
350 REMEDIAL WORKS
During the contract or defects liability period:
Any areas of paving which settle must be re-laid as specified.
Where early traffic leads to migration of the jointing sand refill the joints as specified.