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We are Part of the Thomas Armstrong Group
They are resilient to frost attack in the absence of mobile groundwater and are suitable for use in most soil conditions encountered in the UK. Use of blocks below ground should be carried out in accordance with the recommendations contained in BS 5628 - Part 3.
Our range of concrete blocks are resilient and durable products most of which are perfectly suitable for use below damp proof course (DPC) and as foundation wall blocks. The following block types are suitable for use below damp proof course (DPC) in soil conditions up to DS-3 as defined in BRE Special Digest 1:
Block not recommended for use below damp proof course (DPC):
The presence of mobile water regularly percolating through the blocks can lead to eventual deterioration of the blocks and must be avoided.
Current building practice is such that wherever masonry is used below ground level it is usually limited to the top 1-meter depth. At the same time, sulphate levels in the top 1 meter of UK soils are rarely more severe than class DS-1. It follows that the depth at which samples are taken to enable the sulphate soil classification to be determined should be indicative of the depth where the masonry is being used. BRE Special Digest 1 draws attention to this.
Research by the BRE and the Concrete Block Association has shown that surface carbonation of aggregate blocks enhances their sulphate resistance, the requirement being that blocks are surface carbonated for a minimum of 10 days. Such exposure to air and surface carbonation will always take place without any special provisions between the time of manufacture of the block and back-filling after construction.
Airtec XL and Airtec Standard blocks are suitable for soil conditions DS1 & DS2 as defined in BRE Special Digest 1 and condition MX3.2 as defined in BS EN 1996-2 : 2006.
Airtec Seven, Ultralite 7.3N, Insulite 7.3N and Dense blocks are suitable for soil conditions DS1, DS2 & DS3 as defined in BRE Special Digest 1 and condition MX3.2 as defined in BS EN 1996-2 : 2006.
Thomas Armstrong (Concrete Blocks) Ltd
Part of the Thomas Armstrong Group
T: 01900 68211
F: 01900 602672