Q1. |
What is the current British Standard for
aggregate blocks?
|
A. |
BS EN 771-3 which covers the
BS requirements of all types of concrete block (and brick)
units. Other relevant masonry standards are: BS 8103-2,
BS 5628-1, BS 5628-2 & BS 5628-3. |
| |
Q2. |
What is the
thermal performance (U-value) of a wall incorporating aggregate
blocks? |
A. |
This depends on the type
and thickness of materials used to construct the wall,
including and airspaces. For convenience refer to CBA members
for advice. Alternatively extensive thermal insulation
data is given in BRE Special Digest (SD4) 'Masonry walls
and beam and block floors' available free of charge from
CBA. |
| |
Q3. |
What type of
mortar mix should be used to lay aggregate blocks? |
A. |
Careful selection of mortar
is essential. Extensive guidance is given in the BS 5628
suite of masonry design standards. The location of the
blockwork is an important consideration, and as a guide
stronger mortars will be required in high exposure situations.
Similarly the design of walls employing high strength blocks,
typically 10N/mm or greater, will resulting enhanced loadbearing
capacity when designation (ii) or (i) mortar mixes are
used. However, for the construction of most internal walls
in inner leaves of cavity walls above ground, it is common
practice to specify mortars no stronger than 1:1:6 cement,
lime, sand composition or similar designation (iii) mix
or general purpose to BS 5628-3. |
|
Q4. |
What products can be used
in party wall construction to meet the sound insulation requirements
of building regulations |
A. |
Aggregate blocks can be
used to construct solid and cavity party walls combining
plaster or drylined finishes. For solid walls dense solid
blocks are advocated to construct 215mm walls (100mm blocks
laid flat). For cavity walls 100mm thickness lightweight
or dense aggregate blocks can be used depending on cavity
width and type of surface finish. Aggregate blocks also
feature in a number of Robust Standard Details. These constructions
can be used in a new dwellings without the need for routine
pre-completion testing. CBA members should be approached
for precise specification details |
|
Q5. |
At what intervals are movement
joints required to be provided in aggregate blockwork? |
A. |
Vertical movement joints should
be considered at about 6 to 9 metre intervals, depending
on block type, but their inclusion is not normally required
in internal walls in dwellings. Special attention should
be given to low height panels and areas of high stress concentration.
Guidance is given in BS 5628: Part 3, CBA data sheet 12 or
consult CBA member's literature. |
|
Q6. |
What is the life expectancy
of aggregate blockwork? |
| A. |
Blockwork is normally assumed
to have a service of 60 years, but in practice it is known
to last considerably longer. |
|
Q7. |
Which products are recommended
for direct painting in an industrial environment |
| A. |
Most CBA members can provide
a close textured aggregate block suitable for direct painting.
These products are very robust and provide good resistance
to impact damage |
|
Q8. |
Which products can be used
below ground? |
| A. |
All types of aggregate block
are suitable for use to the inner leaf of external cavity
walls, or internal walls below ground. For the external leaf
of external cavity walls, or solid external walls, dense,
lightweight 7/mm2 blocks or
aggregate block with a density of at least 1500kg/m3 are
all suitable. Where unusual ground conditions exist, or for
more information, please contact CBA members for advice or
see CBA data sheet 3 on sulphate solids. |
|
|
Q9. |
What products are suitable
for use as infill units in beam and block flooring? |
| A. |
A number of products can be
used depending on design requirements. these include dense
and lightweight aggregate blocks 7N/mm2 (solid & cellular),
or 3.5N/mm2 (flooring grade). Generally 100mm thickness blocks
are used. |
| |
|
| Q10. |
What thickness of block is required for a
non-loadbearing partition? |
| A |
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