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Frequently Asked Questions |
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TRADICAL® HEMCRETE® WALLS
Design Questions
Q: Can I use smaller foundations for a Tradical® Hemcrete® house?
A: Yes, you may be able to use shallower/
smaller foundations, subject to the approval
of your Engineer and Local Authority
Building Control Officer.
Q: How thick do the walls have to be to comply with Building Regulations?
A: Yes, providing the temperature is not below
5°C and the material is protected from frost
and heavy rain.
Q:Can Tradical® Hemcrete® be used in a loadbearing capacity?
A: Tradical® Hemcrete® has a compressive
strength of around 0.8 to 1.0N/mm2
(depending on method of application). It is
normally used together with a timber frame
(or steel or concrete), with the frame
transferring the vertical load of the roof and
upper floors. The Hemcrete® can be used
to provide racking strength to the frame if
required.
Q: Is Tradical® Hemcrete® available as blocks?
A: Yes, blocks are available from Lime
Technology Ltd (0845 603 1143). They come
in two grades:
- Structural blocks
Target compressive strength 3N/mm2
Thermal performance Not considered yet
CO2 emission target Carbon neutral
- Thermal blocks
Target compressive strength 1N/mm2
Thermal conductivity 0.11W/m2.K
CO2 emission target 165kg CO2 capture/m3
(superb carbon sequestration)
Q: Is Tradical® Hemcrete® fire proof?
A: Yes, in tests at the CSTB in France 300mm
Hemcrete® blocks lasted for 1hr 40 minutes
and then the mortar joints failed. Monolithic
Hemcrete® walls should perform at least as
well.
Q: Can Tradical® Hemcrete® be used for other building purposes besides walls?
A: Yes, Tradical® Hemcrete® has been
successfully used in France and the UK for
floor slabs, roof insulation and plasters.
These product ranges will be launched in
the near future.
Q: Does Tradical® Hemcrete® need weather protection?
A: Hemcrete® walls are normally finished with
a lime render or covered with a rain-screen
cladding (masonry or timber) of some sort to
protect them from the weather. We expect
to launch a weather proof Hemcrete®, which
will not need rendering, in the near future.
Q: If it is used as an external wall does it need a cavity?
A: No. Tradical® Hemcrete® provides the
insulation and is used as a monolithic (solid)
walling material.
Q: If used as a solid wall does it need additional insulation to comply with part L?
A: No. Provided the wall is a minimum
of 300mm thick it achieves a U-value of
0.3w/m3
(See thermal data sheet)
Q: Does it need movement joints when used in long walls, if so how often?
A: No. The mechanical characteristics
of Tradical® Hemcrete® are such that
movement joints are not normally required.
Q: What protection from rising damp is required?
A: A masonry plinth constructed using lime
based mortar and appropriate building
bricks or blocks and incorporating a
standard dpc conforming to current
standards is recommended.
Q: How air-tight is Tradical® Hemcrete® ?
A: Because Hemcrete® is used to build
monolithic walls, it is extremely air-tight and
air leakage through the walls is negligible.
The actual figure is approx. 0.75 g/m2/mmHg.
Typical air leakage 1-3 air changes/hour @
50 pascals
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