LIGNACITE LTD
NORFOLK HOUSE
HIGH STREET
BRANDON
SUFFOLK IP27 0AX
Tel: 01842 810678
Fax: brandonsales@lignacite.co.uk
Suppliers of: Concrete Blocks Masonry Blocks Dense Concrete Blocks lightweight blocks building Blocks Concrete Blocks Concrete Soffit Blocks concrete
Lignacite are a leading manufacturer of concrete and masonry products and have one of the most efficient and modern manufacturing sites in the U.K.
Sustainable and Environmentally Sensitive Manufacturing
Lignacite sets the standards for sustainable and environmentally sensitive manufacturing. Our curing chambers re-use heat given off by the exothermic reaction between cement and water and when additional heat is needed, gas emissions are pumped back into the chambers, where blocks absorb CO2.
All water used at Brandon comes from a on site borehole, and is recycled at up to 5000 gallons / hour. Sand and aggregate quarried on land adjacent to the plant saves around 36,000 lorry journeys over the period of extraction. The land is then restored on an annual basis for wildlife conservation.
Main Product Ranges:
Concrete Blocks
All our products are Kitemarked as conforming to BS EN 771-3 Aggregate Concrete Masonry Units. They comply with category 1 Masonry Units and are manufactured under a quality assurance scheme assessed and certified to BS EN 9001:2000 by the British Standards Institute.
Lignacite concrete blocks comprise a range of medium density loadbearing units, used in internal or external walls. Lignacite blocks contribute to sound environmental practices as they contain graded wood particles, a selected waste wood product as an alternative aggregate. They also provide exceptional sound reduction qualities.
Concrete Blocks - Lignacite Ash GP:
Ash GP is a medium density concrete block which is robust, durable and suitable for a range of walling applications. Typical uses include the inner leaf of cavity walls when used with cavity insulation, separating or partition walls, and infill blocks in beam and block flooring systems. Ash GP can also be used externally where rendering or cladding is to be applied to the wall. Ash GP blocks provide a strong background for holding fixings. Ash GP is produced using at least 35% of recycled aggregate (by volume) thereby conserving valuable sources of primary material.
Concrete Blocks - Fibo850 Blocks:
Fibo850 is an excellent light weight house builder block. The block is manufactured from expanded clay lightweight aggregate, and contains up to 24% recycled aggregates by volume.
Lignacrete is a robust and durable block that provides a good background for fixing, and that has excellent acoustic properties and thermal capacity. Lignacrete blocks are used in internal or external walls and manufactured from cement, sand and dense aggregates, and contains up to 20% recycled aggregates by volume.
Further technical information is available to download from the BPi download Library or directly from the manufacturer’s own website.
Lignacite - A guide to using concrete blocks below DPC
At Lignacite, our Quoting team is often asked whether concrete blocks can be used below the DPC (damp-proof course) of a structure. To help answer your questions, we’ve put together a guide to help you on your way.
Can concrete blocks be used below DPC?
The short answer is yes, concrete blocks can be used below the DPC in the substructure of a building and walls below ground. Providing they meet the technical requirements of the project, they can be considered a tried-and-tested solution for this application.
Standard grade concrete blocks are sufficiently robust and durable to cater for most types of ground conditions that are encountered in construction. They provide good protection against the risks of freeze-thaw action and saturation. In addition, they tend to have a high level of resistance to a range of chemicals present in soil.
There are other factors, such as compressive strength that should also be considered. As a result, it’s always important to ensure that blocks are suitable for each application.
Considerations when using concrete blocks below DPC
If you’re looking for the right blocks, it’s important to ensure that they are compliant with BS EN 771-3, the European standard for masonry units, as well as Published Document 6697 (PD 6697). These standards both ensure that blockwork meets suitable standards for use.
The key considerations when using concrete blocks below the DPC, according to BS EN 771 and PD 6697, include:
Adequate compressive strength
There is a direct link between the compressive strength of a block and its durability.
Experience has consistently demonstrated that blocks with a strength of 7.3N/mm2 will be sufficiently durable when used in normal ground conditions. Blocks of this strength will also bear the loading of a supporting structure in most low-rise buildings. Higher compressive strengths are available for more demanding loadbearing conditions.
When assessing durability, blocks that are exposed to the external ground are likely to encounter freeze-thaw conditions, accompanied by saturation. Blocks used within the interior of a building are unlikely to be at risk from these conditions, so blocks with a lower compressive strength, such as 3.6N/mm2, can be specified.
Freeze-thaw resistance
Most types of concrete blocks will provide adequate resistance to saturation accompanied by freeze-thaw action. In the UK, it is the masonry located typically 150mm above and below the finished ground level that is more susceptible. In this zone, the masonry can become wet for long periods, particularly in the winter months.
Density
Experience has shown that the density of a block is a reliable measure of its durability. For use below the DPC, it is recommended by PD 6697 that aggregate concrete blocks with a net density of ≥1500kg/m3 or greater can be used in conditions where there is a high risk of saturation with freezing.
Soil conditions
Sulfates and acids are chemicals that are often found in soil and groundwater. When they come into contact with concrete, they can react with the materials in the mixture, resulting in a chemical reaction. This may cause disruption to the materials within the block. If the ground that you’re building in has a high acid or sulfate content, it is important to use blocks that can withstand these conditions.
In the case of sulfate-bearing soils you may need to consider using sulfate-resisting mortar.
Mortar
The durability of concrete blocks is assured when a compatible mortar mix is specified. For use in soil conditions where there is a risk of saturation with freezing, a mortar strength Class M6 should be used. Typically, this will correspond to a mortar with proportions of 1:1/2:41/2 cement:lime:sand. For use in less onerous soil conditions, a mortar strength Class M4 or M6 should be used.
What blocks can be used below DPC?
A variety of block types can be used below DPC. As mentioned above, the compressive strength and density of blocks are the primary characteristics that influence the durability performance when used below the DPC level.
NHBC guidance says that blocks used below the DPC should meet BS EN 771-3 standards in addition to at least one of the following criteria:
Minimum density of at least 1500kg/m3.
Minimum compressive strength of 7.3N/mm2 in order to withstand pressure from the structure above and the ground around it.
Meet Technical Requirement R3, to ensure they are suitable for the intended use.
Within our own product ranges, we have several concrete blocks that are suitable for use below a DPC.
Lignacrete Concrete
Lignacrete Standard blocks with compressive strengths of 7.3 N/mm2 and 10.4N/mm2 are suitable for use below DPC. They are frost resistant in accordance with PD 6697 and certified to BS EN 771-3. They are dense blocks and can be considered for use in cavity and single-leaf walls in this location.
Find out more.
Ash GP Concrete
Ash GP medium-density blocks are certified to BS EN 771-3 and available with compressive strengths of 7.3N/mm2 and 10.4N/mm2. This makes them suitable for use below DPC.
Find out more.
Fibo 850 Concrete
Fibo 850 low-density blocks have a compressive strength of 3.6N/mm2. They can be used to construct interior walls below DPC.
Find out more.
The benefits of using concrete blocks below DPC
Concrete blocks are generally a better choice for use below DPC than bricks because they are more efficient to lay (one block is the equivalent of six bricks).
If you select the right product for your project, they will be highly durable and able to withstand the effects of frost and damp, as well as the pressure from surrounding forces. As such, you’ll know that the materials are durable, with a long life, giving you complete peace of mind about the longevity of the structure.
Find the right blocks for your next project
Seeking concrete blocks for your next project? Take a look at our Block Application tool, which guides you through where our blocks can be used. Alternatively, give our friendly Quote Line a call on 01842 778485 to discuss your needs with a member of our team.
An introduction to medium dense blocks: their properties, benefits and uses
We take a closer look at medium dense blocks and how they could be used in your next building project. Read on to learn more.
Looking for a strong and durable concrete block for your building project? A dense concrete block isn’t your only option! In this article, we’ll introduce you to the medium dense block and demonstrate why it could be the perfect alternative for your build.
What is a medium dense block?
A medium dense concrete block is a popular construction material that offers builders strength, durability and excellent sound and thermal insulation. They are lighter than standard dense blocks, which makes them easier to handle and reduces the overall load on a structure. Typically, they have a density that ranges from 1,100 to 1,600 kg/m³.
Medium dense blocks can be used in both load-bearing and non-load-bearing walls, partitions and other structural elements in residential, commercial and industrial buildings.
What's the difference between dense and medium dense blocks?
The difference between dense and medium density blocks is their weight and density. Dense blocks are heavier due to their composition, which features dense, tightly packed aggregates. This gives them impressive strength, which makes them ideal for heavy-duty structural applications.
Medium dense blocks, on the other hand, are lighter. Their composition includes a proportion of lightweight aggregates but they retain many of the qualities of dense blocks. In addition, they also have good thermal and excellent acoustic insulating qualities.
Read more: Learn more about the properties of dense blocks.
The properties of medium dense blocks
Medium dense blocks tend to have densities that range from 1,100 to 1,600 kg/m³. The exact weight of each block will depend on this density, along with the block’s size and its mix. For instance, our 140mm Lignacite SP blocks have had their mix optimised to produce a solid block that weighs less than 20kg per unit.
Medium dense blocks are known for their strength and durability. For example, our Lignacite solid block and Ash GPmedium dense blocks have loadbearing strengths of up to 10.4N/mm². This makes them an excellent choice for substantial structures.
Another key feature of medium density blocks is their insulative properties. These blocks have a relatively low thermal conductivity, which means that they can help to keep buildings warm. For example, our 100mm Lignacite blocks (with a moisture content of 3%) have thermal conductivity of 0.90 W/mK while our 140mm SP blocks have an even lower conductivity score of 0.79W/mK.
They have excellent sound-insulating properties too. Their relatively high mass with low levels of porosity helps to block external and internal sound effectively. Walls built with our 140mm Lignacite SP blocks can therefore give sound insulation in excess of 50db (Rw).
Read more: Find out more about the sound insulation properties of Lignacite blocks.
What are medium dense concrete blocks used for?
The strength and durability of medium density blocks makes them very versatile. They can be used to build homes, shopping centres and stadiums, and you can use them for internal and external applications. You can even use them below ground!
Here are just some ideas of what you can use medium density concrete blocks for:
Inner and outer leaves of external cavity walls
Internal walls (including fire break walls)
Separating or partition walls
Below ground
Infill for block and beam flooring
You can find out more about how different blocks can be used with our Application Locator tool.
The benefits of using medium dense blocks
There are several advantages to using medium density blocks in your building projects.
Durability: The strong durability and impact resistance of medium dense blocks means that they can be used in structures for commercial, leisure and academic use.
Excellent sound insulation: Medium density blocks can ensure the comfort of inhabitants and can help to protect them from excess noise pollution thanks to their fantastic sound insulation.
A1 fire rated: Medium density concrete blocks make no contribution towards fire and are completely non-combustible.
Air tightness: Medium dense blocks, such as our Lignacite product, have very low air permeability, particularly if their surface is painted.
Find the right medium dense block for your project
If you're looking for the right medium density blocks for partition walls, external walls or cavity walls, get in touch with our friendly Quoting Team by calling 01842 778485 today.
You can also visit our dedicated web pages on our Lignacite and Ash GP medium density blocks to see if they fit your specifications.
