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- Brick Size Tolerance and Durability Classification
All our facing bricks are manufactured to the clay masonry product standard BS EN771-1. This standard defines the dimension and tolerance and durability classes used in our specifications.
Dimensional Tolerance Classes; T2, T1 and Tm (T2 being the defined tightest).
Durability is defined as; F2 – frost resistant F1 – Moderately Frost Resistant
A more detailed explanation can be found in technical guidance note; EN771 Explained Durability and Size.pdf
- Brickwork Bonds & Net Quantities per m²
Please download the following guidance document for Brickwork Bonds & Net Quantities per m²
- Brickwork Movement and Expansion Joints
Clay bricks are subject to expansion and contraction when exposed to heat and moisture, which can cause damage in brickwork if the design does not cater for it. An expansion allowance of 1 mm/m is recommended for all Michelmersh facing brick ranges.
- Brickwork Operation & Maintenance Information
Please download the following guidance document for Brickwork Brickwork Operation & Maintenance Information
- Cleaning Brickwork
Care should always be taken when cleaning brickwork. It is important to know what type of stain you are trying to remove and the correct materials and techniques to use. Full guidance can be found in the following document; Cleaning of clay brickwork.pdf but there are some basic rules to consider;
- Incorrect use of pressure washers can severely and irrevocably damage brickwork, and should be avoided on sand faced product.
- Conventional acid based cleaning agents should not be used if vanadium staining is present.
- Prevention is Better than Cure; A great deal of time and effort can be saved if appropriate care is taken to avoid contamination of brickwork during construction.
- Correct Mixing of Bricks
Unless specifically instructed otherwise all bricks should be laid from a mix of at least three packs. Whilst every effort is made to ensure consistency some products can show slight variation between batches and loads should be checked for colour consistency and where possible mixed further to obtain a consistent blend or their use managed to avoid ‘banding’ in areas of brickwork already.
- Cutting Bricks
Bricks should be cut using a wet saw supplied with a constant flow of clean water. Dry cutting or the use of dirty recirculated water can result in a build-up of dust / slurry on the face of the bricks which is often impossible to remove without having a detrimental effect on the appearance of the product.
Cutting and drilling of bricks should be carried out in accordance with all relevant safety and environmental requirements.
- Firecracking, Crazing & Oil-Cracking on Bricks
Please download the following guidance document: Firecracking, Crazing & Oil-Cracking on Bricks
- Guide on use of facing bricks below DPC
By definition bricks that sit below the DPC will be exposed to potential saturation from water migrating from the ground up through the brickwork. In such a situations it is important to choose bricks that are both Frost Resistant (F2) and have low Active Soluble Salts content (S2) as defined in EN771-1 Standard for Clay Masonry Units.
All our facing brick products meet the F2/S2 classifications and as such are suitable for use in locations subject to severe exposure. This includes areas above and below ground level (approximately 2 courses above and below).
Bricks used deeper below ground level, whilst equally saturated, are less likely to be subjected to freezing conditions.
Please download the following Guide on use of facing bricks below DPC
- Site recommendations for brickwork
Please download the following guidance document: Site recommendations for brickwork
- Which way up to lay bricks with frogs
It is always advisable to lay bricks frog up, there are several reasons for this;
Laying frog up ensures the frog is fully filled with mortar which could otherwise compromise the overall strength of the brickwork.
If the 'Smiles/Folds' are laid upside down, there is a possibility that dirt could accumulate in them which could encourage plant / moss growth in some situations.
(A frog is the indentation in the top of a handmade or stock brick)
- Laying Clay Pavers
Clay pavers are made from a natural material which produces their distinctive look and colourfast durability. It also means that there will be variation in size that must be accommodated for during the laying process. Key point to remember are;
- Always set out using sufficient ‘string’ lines, regularly check alignment with them and pavers adjusted to suit.
- Nibs on our pavers are intended to prevent joints becoming too small and do not have to be butted up against the adjacent paver.
- The final joint width should be adjusted to maintain alignment with the relevant string line, and should be between 3 – 6mm
Detailed information on the design and construction of paving is set out in the BS7533 codes of practice series.
- Sealing Pavers
We do not recommend the sealing of clay pavers. Clay pavers retain their colour throughout their lives and sealing pavers will have no benefit. Sealing clay pavers can even have detrimental effects by preventing the natural movement of moisture in and out of the product.
- Cleaning Pavers
Blockleys wire cut pavers can be regularly jet washed and scrubbed with stiff, non-metallic, brushes if necessary. More care should be taken when cleaning our rustic pavers to avoid damaging the texture.
Algae and moss can sometimes build up on areas of paving, especially those in shaded area and or near trees. This can be removed by first cleaning off as much as much growth as possible and then treating with a proprietary algaecide or moss killer in accordance with the manufactures instructions.
Oil; once penetrated the surface of a paver is difficult to remove, however in non-bound applications using our clay pavers it is often possible to lift individual pavers and ‘spin’ them over to present the clean lower face instead.
- Using Bricks as Pavers
Whilst our facing bricks are suitable for use in a wide range of building applications, including non-vertical and horizontal locations, we cannot recommend or guarantee their use in a paving situation. Our facing bricks are tested and sold to standards relevant to clay facing bricks (BS EN 771-1 et al). As such they are not suitably attested as paving materials and we are not in a position to sell them as such.
The company does supply a range of Clay pavers both in Wirecut and more traditional Rustic textures.
- Light Reflectance
Light reflectance levels for our Blockleys Pavers are as follows;
- Correct Mixing of Pavers
Unless specifically instructed otherwise all pavers should be laid from a mix of at least three packs to avoid ‘patches’ or sudden changes.
Whilst every effort is made to ensure consistency some products can show slight variation between batches and loads should be checked for colour consistency and where possible mixed further to obtain a consistent blend.
It is good practice to ensure all the pavers laid in a particular area are obtained from the same batch stock. If space is tight it is worth discussing this with your stockist.
- Michelmersh BS Specials
Please download the following guidance document for Michelmersh BS Specials
Click here for 2019 Brick Environmental Product Declaration Report.
Further information visit: http://www.brick.org.uk/technical/guides.
If you have any technical queries please contact us at the following email address: email@example.com.