Your technical questions answered
We have put together some typical questions you may have around industry terminology and general technical understanding, with of course some basic answers that will hopefully help broaden your knowledge a little.
There are a suite of European standards covering the testing and performance of all paving products from BSEN 1338 for concrete pavers to BSEN 1344 for clay, Hardscape can advise which are relevant to your needs and the minimum requirements of your specified materials.
Both the HSE and UK guideline for slip/skid resistance as well BSEN 1341 gives a value of anything over 35 as being safe, annexe C of BS7533 part 12 gives a PTV (pendulum test value) value of 40 for pedestrian use and 45 for trafficked areas. Typical unpolished slip resistance example for Royal White granite: 65.5 (wet)
This would normally be worked out by your site engineers based on CBR value’s and traffic loadings but generally both build ups will be similar in materials thickness.
BSEN1341 4.2 tables 1 / 2 / 3 shows the varying permissible tolerances for stone paving depending on plan and thickness dimensions but on a 80mm thickness it would be +/- 4mm.
Efflorescence is a powdery deposit of salts which forms on the surface of bricks and mortar. It is usually white but efflorescence may be yellow, green or brown. A definition for efflorescence is a staining of brickwork, masonry and concrete, caused by salts being washed out of construction materials, and being deposited on the surface of building materials by the evaporation process of water.
The most typical bedding and jointing materials are sand and cement though these days many applications look to proprietary mortars which can contain a polymer to aid adhesion and strength.
Hardscape can supply on request both CE and Declaration of Performance certificates for the materials we supply.
By definition a line that links two points on a circle or curve. Below is a formula for the length of a chord if you know the radius and central angle:
r is the radius of the circle
c is the angle subtended at the centre by the chord
sin is the sine function
or below is a formula for the length of a chord if you know the radius and the perpendicular distance from the chord to the circle center. This is a simple application of Pythagoras’ Theorem:
r is the radius of the circle
d is the perpendicular distance from the chord to the circle centre.
Within BSEN 1341 annexe A is a calculation to give guidance on the appropriate thickness and breaking loads for intended classes of use. Hardscape have a working understanding of this calculation and can, as required, give guidance.
Permeable paving is a range of sustainable materials and techniques for permeable pavements with a base and Sub base that allow the movement of stormwater through the surface. In addition to reducing runoff, this effectively traps suspended solids and filters pollutants from the water.
The Building Regs part M require reasonable provision to be made for the access to a building and use of facilities within a building for disabled and less able bodied people, this also includes for the provision of “markers” such as tactiles and visibility strips on stairways to enable clear and defined passage.
If you find that there is something not covered here or would like further information about a particular subject covered then please fill in the contact form at the foot and we will get back to you as quickly as we can.